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Use, fate and ecological risks of antibiotics applied in tilapia cage farming in Thailand
... However, the studies about risk threshold in sediment was less than that in water. Researchers usually converted the concentration of pollutants in sediment to that in water; then, the risk of pollutants in sediment was analyzed based on the risk threshold of water [24][25][26]. In recent years, some researchers proposed to calculate PNEC in sediment (PNEC sediment ), based on the Equilibrium Partitioning approach (EqP) [27]. ...
... mg/kg. Comparing with previous risk studies, researchers usually converted antibiotic concentrations in sediment to concentrations in water, due to the lack of toxicity data in sediment; then, the risk was assessed based on the risk threshold of CAs in the water, which cannot reflect the local characteristics of the water and sediment [24][25][26]28]. ...
... Different to CHL and THI, the risk area of FF was the lowest; only 8.7% of the area showed a low-risk level in the whole basin. risk studies, researchers usually converted antibiotic concentrations in sediment to concentrations in water, due to the lack of toxicity data in sediment; then, the risk was assessed based on the risk threshold of CAs in the water, which cannot reflect the local characteristics of the water and sediment [24][25][26]28]. ...
Chloramphenicol antibiotics (CAs) are broad-spectrum antibiotics which are widely used in the prevention and treatment of infectious diseases in livestock and poultry breeding. However, overused CAs can enter the watershed and eventually enter the sediment. Antibiotics in sediment can cause secondary pollution through disturbance and suspension. In this study, taking the Fenhe River Basin as the research area, the risk of CAs in sediment were assessed by collecting sediment samples. The results showed that CAs were detected in all sediment samples of the Fenhe River Basin. The mean concentration of CAs was 79.1 μg/kg, and the concentration of thiamphenicol (THI) was dominant, which was up to 58.3 μg/kg. Temporally, there are great differences in different seasons; the concentration of CAs was higher in winter than that in summer, up to 4.79–174 times. Spatially, the mean concentration of CAs in midstream was 83.5 μg/kg, which was higher than that in the upstream and downstream. The concentration of CAs in tributaries were generally higher than that in the main stream, and the mean concentration of tributaries was 1.1 times that of the main stream. CAs in S2 (Lanhe River) was the most prominent among all sample sites; the concentration of CAs was 190.8 μg/kg. The risk threshold of CAs in the sediment was calculated using the Equilibrium Partitioning approach (EqP), based on the distribution coefficient (Kp) and the predicted no-effect concentration (PNEC) in the water, and the values were 0.091–1.44 mg/kg. Based on the risk threshold, the ecological risk of the CAs in sediment was assessed using risk quotients (RQ). The results showed that the Chloramphenicol (CHL) was the most prominent in the Fenhe River Basin, and the proportion of medium-risk areas reached 21.7%, while all the other areas showed low risk. Secondly, the proportion of medium-risk areas was 17.4% for THI, and all the other areas showed low risk. The risk for Florfenicol (FF) was least among all CAs, and the proportion of low-risk areas was only 8.7%, while all the other areas were of insignificant risk.
... In many countries, Nile tilapia are reared in intensive cages in rivers and canals that are often polluted with drainage water [2,3]. In such conditions, fish are likely to suffer from low water quality and infectious pathogens [4], and farmed fish are frequently infected by pathogenic bacteria, such as Streptococcus spp., Flavobacterium, Edwardsiella spp., Francisella spp., and Aeromonas spp., causing high mortality rates and substantial economic impacts [5][6][7][8][9][10][11][12]. Antibiotics and traditional chemotherapies are usually applied to control infection and reduce mortality during disease outbreaks [4,13]. ...
... In such conditions, fish are likely to suffer from low water quality and infectious pathogens [4], and farmed fish are frequently infected by pathogenic bacteria, such as Streptococcus spp., Flavobacterium, Edwardsiella spp., Francisella spp., and Aeromonas spp., causing high mortality rates and substantial economic impacts [5][6][7][8][9][10][11][12]. Antibiotics and traditional chemotherapies are usually applied to control infection and reduce mortality during disease outbreaks [4,13]. However, the use of antibiotics impairs the natural immune response of fish and promotes the development of strains of pathogenic bacteria that are resistant to antibiotics, encouraging their use in even larger quantities [14,15]. ...
... Hence, there is a need to find alternative strategies to combat the risk of bacterial infections in fish cultures [21][22][23]. Vaccines can provide long-lasting protection against pathogenic bacteria and viruses [24][25][26] and are now widely used to control infectious diseases in many aquatic organisms [4,27]. A wide range of vaccines have been developed to protect Nile tilapia against infectious diseases; these include live attenuated vaccines against Streptococcus agalactiae [15,28], polyvalent vaccines against streptococcosis or lactococcosis [29], novel chimeric multiepitope for streptococcosis [30], and vaccines based on formalinkilled bacteria [31]. ...
Vaccines prepared from formalin-killed Streptococcus agalactiae were administered to Nile tilapia (Oreochromis niloticus) via three different routes: immersion in a water-based vaccine, injection with an oil-based vaccine, and as a water-based oral vaccine. All vaccination treatments increased lysozyme and peroxidase activity in skin mucus of Nile tilapia by 1.2-to 1.5-fold compared to their activities in unvaccinated control fish. Likewise, alternative complement, phagocytosis, and respiratory burst activities in the blood serum of the vaccinated fish were 1.2-to 1.5-times higher than in the unvaccinated fish. In addition, the expression transcripts of interleukin-1 (IL-1), interleukin-8 (IL-8), and lipopolysaccharide-binding protein (LBP) were 2.3-to 2.9-fold higher in the vaccinated fish compared to those in the unvaccinated control. The unvaccinated fish challenged with Streptococcus agalactiae had a survival rate of 25% compared to a survival rate of 78-85% for the vaccinated fish. The differences between the unvaccinated and vaccinated fish were all statistically significant, but there was no significant difference in any of the indicators of immunity between the three vaccinated groups. Collectively, these results confirm that vaccination with formalin-killed Streptococcus agalactiae significantly improved the resistance of Nile tilapia to infection by the pathogen. Overall, the efficacy of oral administration of the vaccine was comparable to that of vaccine administered via injection, indicating that oral vaccination is a viable cost-effective alternative to administering vaccines by injection. Citation: Linh, N.V.; Dien, L.T.; Dong, H.T.; Khongdee, N.; Hoseinifar, S.H.; Musthafa, M.S.; Dawood, M.A.O; Doan, V.H. Efficacy of Different Routes of Formalin-Killed Vaccine Administration on Immunity and Disease Resistance of Nile Tilapia (Oreochromis niloticus) Challenged with Streptococcus agalactiae. Fishes 2022, 7, 398.
... Veterinary antibiotics are indispensable inputs for aquaculture practices. While both prophylactic and therapeutic uses of antibiotics are very effective in promoting aquacultural yields, the subsequent effects of antibiotics on water quality have largely been ignored [1][2][3]. Antibiotic-contaminated discharge water usually receives zero or insufficient treatment prior to being released into downgradient watersheds. Subsequently, these untreated antibiotics may affect the environment by introducing antibiotic-resistant pathogens or killing waterborne microorganisms [4]. ...
... h −1 ). According to the general rate equation (Equation (1)), the 2nd order rate constant (k n ) can be calculated from Equations (2) and (3): ...
Copious use of antibiotics in aquaculture farming systems has resulted in surface water contamination in some countries. Our objective was to develop a slow-release oxidant that could be used in situ to reduce antibiotic concentrations in discharges from aquaculture lagoons. We accomplished this by generating a slow-release permanganate (SR-MnO4−) that was composed of a biodegradable wax and a phosphate-based dispersing agent. Sulfadimethoxine (SDM) and its synergistic antibiotics were used as representative surrogates. Kinetic experiments verified that the antibiotic-MnO4− reactions were first-order with respect to MnO4− and initial antibiotic concentration (second-order rates: 0.056–0.128 s−1 M−1). A series of batch experiments showed that solution pH, water matrices, and humic acids impacted SDM degradation efficiency. Degradation plateaus were observed in the presence of humic acids (>20 mgL−1), which caused greater MnO2 production. A mixture of KMnO4/beeswax/paraffin (SRB) at a ratio of 11.5:4:1 (w/w) was better for biodegradability and the continual release of MnO4−, but MnO2 formation altered release patterns. Adding tetrapotassium pyrophosphate (TKPP) into the composite resulted in delaying MnO2 aggregation and increased SDM removal efficiency to 90% due to the increased oxidative sites on the MnO2 particle surface. The MnO4− release data fit the Siepmann–Peppas model over the long term (t < 48 d) while a Higuchi model provided a better fit for shorter timeframes (t < 8 d). Our flow-through discharge tank system using SRB with TKPP continually reduced the SDM concentration in both DI water and lagoon wastewater. These results support SRB with TKPP as an effective composite for treating antibiotic residues in aquaculture discharge water.
... Although, tilapia was once considered disease resistant, nowadays its farming is suffering by frequent occurrence of devastating diseases mainly due to the use of excessive feeds, chemicals and increase in intensification (Wu et al., 2013). Tilapias are often stocked over 100 fish/m 3 of cage volume or overcrowding and periodic handling, and also affected sudden rise and fall in temperature, poor water quality and poor nutritional status leading to stress or immunosuppressant causing increased susceptibility to infection by parasite, bacterial and viral diseases e.g., Streptococcus sp., Aeromonas sp., Edwardsiella sp., Pseudomonas fluorescens, Vibrio anguillarum, Flavobacterium columanare, Tilapia Lake virus etc. (Plumb, 1997;Belton et al. 2009;Bhujel, 2014;Rico et al. 2014;Reverter et al. 2014). ...
... Various antibiotics and other chemicals are used to control these pathogens in tilapia farms, but the use of antibiotics as immune stimulants can be harmful to animals, consumers, and the environment (Alderman and Hasting, 1998;Watts et al. 2017). The most used antibiotics is oxytetracycline which was found to be used by 45% of the farmers followed by enrofloxacin (6%) and sulfa-dimethoxine (6%) in Northern Thailand (Lebel et al. (2013), Whereas in Central Thailand have found five groups of chemicals: namely, ß-lactams, quinolones, sulfonamides, tetracyclines, diaminopyrimidines (Rico et al. 2014). In these areas, the most used antibiotics were enrofloxacin (59% of the interviewed farmers), followed by oxytetracycline (48%), amoxicillin (28%), and sulfadiazine or trimethoprim (28%). ...
The present trial was conducted to evaluate whether Biotronic® Top Liquid (BTL) supplementation would benefit during the nursing of Nile tilapia (Oreochromis niloticus) fry in terms of survival, growth, and disease resistance. Isonitrogenous (22.9±0.2% CP) diets were prepared by supplementing 0.0, 0.5, 1.0, 1.5, 2.0 to 2.5 L/ton of BTL diet i.e. T1 to T6, respectively. Each of the 18 aquaria (100 L) was stocked with 45 fish (16.17±0.40g, Mean±SE) having three replicates per treatment. During the trial, fish biomass increased linearly with the increase in BTL dose i.e. 230g (10.3%) of fish biomass/L of BTL. Results showed that higher dose of BTL/ton of feed resulted in to increase growth rate, with an indication of improved growth beyond the tested level i.e. >2.5 L/ton. Bacterial challenge test using Aeromonas hydrophila showed that the highest BTL dose could maintain average fish survival rate above 65%, which was 25% higher than that of control. Average survival improved linearly i.e. (y)=8.857x+40.317 (R²=0.64) with a nearly 9% increase in survival per liter of BTL supplementation. BTL improved SGR, DWG, and PER by 3.4, 1.6 and 2.1 times, respectively as compared to the control when the fish were challenged by bacteria. Therefore, the dose of 2.5 L/ton of feed is recommended based on the present study.
... OTC concentrations estimated in this study fell within the range of ng L −1 -μg L −1 measured in aquatic environments covering surface water, groundwater, runoff, and WWTP influent and effluent across different countries (Rico et al., 2014;Pereira et al., 2015;Xiong et al., 2015;Kim et al., 2017;Muñoz et al., 2017; FIGURE 7 | Effect of reduction in OTC emission rate on tetracycline genes selection rate (day −1 ) in water environment of (A-G) aquaculture ponds and (H,I) a river section within basins at exceedance risk (ER) 0.2, 0.5, and 0.8 during spring, summer, autumn, and winter. E50 and BMR10 are 50 and 10% increase in tetracycline genes selection rate, respectively, which are corresponding to EC50 and BMC10 in the concentration-response relationship. ...
... There are studies exploring the effect of aquaculture used OTC on their surrounding environment. Rico et al. (2014) conducted farm-and river-scale monitoring for OTC in Thailand. The detection rate of OTC in rivers during the wet season was higher than that during the dry season with a maximum measured concentration of 3.1 μg L −1 . ...
Oxytetracycline (OTC), one of the most important antibiotics in aquaculture industry, has been linked to emergence of antibiotic resistant genes in the aquatic environment. Given rapid growth of the aquaculture industry and unregulated use of antibiotics, it is necessary to implement measures to mitigate the impact of antibiotic resistance risk on environmental and human health. However, there is a lack of quantitative models to properly assess risk of antibiotic resistance associated with environmentally relevant antibiotic residues. To address this issue, here we developed a computational framework to assess antibiotic resistance risk posed by low-concentration OTC in aquaculture ponds and rivers across Taiwan regions. To this end, estimated amount of aquaculture used OTC as a crucial input parameter was incorporated into a multimedia fugacity model to predict environmental concentrations of OTC in surface water/sediment. A pharmacodynamic-based dose-response model was used to characterize the OTC concentration-antibiotic resistance relationships. The risk of antibiotic resistance selection in an aquatic environment could be assessed based on a probabilistic risk model. We also established a control measure model to manage the risks of substantial OTC-induced antibiotic resistance impacts. We found that OTC residues were likely to pose a high risk of tetracycline resistance (tetR) genes selection in aquaculture ponds among all the study basins, whereas risk of tetR genes selection in rivers experienced a variably changing fashion. We also showed that it was extremely difficult to moderate the tetR genes selection rates to less than 10% increase in aquaculture ponds situated at northeastern river basins in that the minimum reductions on OTC emission rates during spring, summer, and autumn were greater than 90%. On the other hand, water concentrations of OTC during spring and summer in southwestern rivers should be prioritized to be severely limited by reducing 67 and 25% of OTC emission rate, respectively. Overall, incorporating a computational fugacity model into a risk assessment framework can identify relative higher risk regions to provide the risk-based control strategies for public health decision-making and development of robust quantitative methods to zero-in on environment with high risk of tetR genes selection in relation to aquaculture-used pharmaceutical residues.
... For instance, erythromycin was found to vary from 0.8 ng/g to 4.8 ng/g in sediment samples from aquaculture areas in Hailing Island in Southern China [9]. Oxytetracycline (OTC) and enrofloxacin (ENR) in sediment in the Tha Chin and Mun rivers have concentrations ranging from 4.5 µg/kg to 4062 µg/kg and from 1.4 µg/kg to 2239 µg/kg, respectively [16]. Wang et al. detected nine antibiotics in the aquacultural feed, including sulfamethoxazole (SMX), levofloxacin (LEOF), oxytetracycline (OTC), chlortetracycline (TC), norfloxacin (NOF), and tetracycline (TC) with concentrations ranging from 1.10 µg/kg to 46.45 µg/kg. ...
... Unlike TMP, OTC had minor changes before March and significantly decreased in April. The enhanced degradation rate of OTC is likely attributed to direct photodegradation [16]. In addition, the plant roots may have changed the properties and structure of the sediment and promoted biodegradation. ...
Photodegradation remains the major pathway of antibiotic removal in natural ponds. This study introduced a new method of growing vegetables on the bottom substrate of shrimp ponds to improve sediment quality. The aim of the study was to investigate the effect of vegetable planting on the photodegradation of antibiotics. This study characterized antibiotic levels in the pond sediment during this phytoremediation process and investigated the antibiotic content and composition of the sediment with and without crop rotation (traditional control), as well as the shrimp yields. The results showed that total antibiotics (e.g., trimethoprim, oxytetracycline, and norfloxacin) in the sediment of all aquaculture ponds continuously decreased from 44.78 ± 4.07 μg/kg to 18.80 ± 2.26 μg/kg in the crop rotation pond. The total amount of antibiotics consistently decreased in all ponds, and the rate of decline did not greatly differ. However, oxytetracycline in the crop rotation pond decreased faster than in the control pond, presumably because the growing vegetables altered the sediment and microbial-community characteristics that promoted oxytetracycline degradation. In the following year, there was little difference in the levels of norfloxacin or oxytetracycline between the two ponds. An increase in trimethoprim in the control pond was much higher than in the crop-growing sediment. It was indicated that the system remediated the shrimp pond ecosystem as well as providing the possibility of increasing profits by planting vegetables in the winter idle period of shrimp ponds.
... The use of chemicals and antibiotics represents a potential risk to both the consumers and the environment because of their tendency for bioaccumulation and their residues in fish tissues [10]. Moreover, there is another major concern associated with antibiotic use in aquaculture, namely, the possible development of antibiotic-resistant bacterial strains [13]. Antibiotic resistance occurs when bacteria are exposed to antibiotics at sub-therapeutic levels for extended periods, and the bacteria can evolve antibiotic-resistant genes or plasmids [14]. ...
... Microorganisms can produce natural substances to prevent or inhibit pathogenic microbes [13]. Microbes can display both specific resistance and multi-resistance. ...
Probiotics are live beneficial bacteria introduced into the gastrointestinal tract through food or water, promoting good health by enhancing the internal microbial balance. Probiotic microbes produce bacteriocins, siderophores, lysozymes, proteases, and hydrogen peroxides, inhibiting the growth of harmful pathogens. Such beneficial bacteria also produce many enzymes such as amylase enzyme by Aeromonas spp., Bacillus subtilis, Bacteridaceae, Clostridium spp., Lactobacillus plantarum, and Staphylococcus sp., and protease and cellulase enzymes by B. subtilis, L. plantarum, and Staphylococcus sp. In aquaculture, probiotics confer several benefits and play important roles in improving growth performances, disease resistance, immunity, health status, intestinal epithelial barrier integrity, gut microbiome, and water quality. In addition, the practical application of probiotics in aquaculture diets could minimize antibiotic side effects. Promoting these feed additives for fish would help to improve their productive performance and feed utilization and, therefore, boost fish production and safeguard human health. This review provides updated information regarding definitions, sources of bacterial probiotics, probiotic use in fish diets against pathogenic bacteria, mechanisms of action, beneficial aspects, and potential applications of probiotics in fish. It is anticipated that these will be of significant value for nutritionists, agricultural engineers, researchers, pharmacists, scientists, pharmaceutical industries, and veterinarians.
... Applied to farmlands, the active ingredients reach the upper soil layer, where they either accumulate or may be rinsed off into surface waters or may leach to groundwater where they can impact both human and environmental health. Massive discharges of antimicrobials into the environment have been reported with high levels in soil [13], sediment [14] as well as surface and groundwater [15]. Such presence is one of the factors contributing to the spread of antibiotic resistance [16]. ...
The use of antimicrobials in livestock production and their effect on the development of antimicrobial resistance (AMR) is a global health problem for humans, animals and the environment. The aim of this study was to determine antimicrobial residue levels in milk and feces samples during the withdrawal period in dairy cattle administrated with a single dose of the drug, as well as to characterize the antimicrobial resistance patterns of Escherichia coli cultured from feces samples. In the study, dairy cows from three different farms in North Macedonia were included. Raw milk and feces samples were collected before drug administration (0 day) and on the 1st, 2nd, 3rd, 7th and 21st day after drug administration. The antimicrobial residues of oxytetracycline, enrofloxacin, amoxicillin, trimethoprim and procaine-benzylpenicillin were determined using a validated liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method involving stable isotopes. According to results obtained, the highest levels of analyzed antimicrobial residues were determined on the first day after drug administration, which then gradually decreased until their elimination (7th day). The highest AMR of E. coli (100%) was found in β-lactam antimicrobials. Less exposure to broad-spectrum antimicrobials could be an important factor for reduction of AMR on dairy farms.
... The photocatalytic potential of the chitosan-modified ZnO QDs was investigated in the photodegradation of OTC under fluorescent light irradiation. The OTC is a common type of antibiotic most widely used and is employed in both farming (especially aquaculture) and human life [30,31]. The effects of the initial concentration of OTC, the photocatalyst dosage, and the photocatalyst's pH environment and stability were investigated. ...
This study explores the ability of chitosan to control the size of ZnO quantum dots (CHT/ZnO QDs) and defects formation via the microwave-assisted method, as well as their photocatalytic oxidation activity towards oxytetracycline (OTC). The intramolecular and intermolecular hydrogen bonds within the chitosan -OH and -NH2 were altered by ZnO and microwave radiation. As a result, the particle size decreased from 9.35 \(\pm\) 0.21 nm to 7.86 \(\pm\) 0.28 nm. Additionally, the presence of chitosan led to higher oxygen vacancies (\({\text{V}}_{\text{s}}\)o) and Zni interstitials. The small size enhanced the absorption of photons, while defects suppressed the recombination rate of photogenerated electron/hole (e−/h+) pairs. The synthesized CHT/ZnO QDs exhibit outstanding photocatalytic performance by removing 97.4% of OTC within 40 min through pseudo-first-order kinetics with the rate constant (k) of 0.0568 min−1 and driven by the h+ and \({\rm{O}}_2^{ \cdot - }\). This result was achieved by comprehensively investigating the impact of pH condition, initial concentration of OTC, and photocatalyst dosage. We believe that this work provides a potential photocatalyst design for antibiotics removal.
... Antibiotics and pharmaceuticals are known to reach aquatic ecosystems, potentially causing long-term risks to aquatic and terrestrial organisms associated with such ecosystems [83][84][85]. In fact, one of the antibiotics we used, enrofloxacin, is one of the most used antibiotics in human and veterinary medicine [86], and although it has not been found to cause significant mortality in Rhinella arenarum tadpoles [86], it can cause growth and development suppression (in doses higher than 10µg/L) in R. arenarum tadpoles [86]. ...
Simple Summary
Gut microbiomes can influence host health and fitness. Pollutants, including antibiotics, tend to alter microbiomes. We examined the role of an undisturbed gut microbiome on tadpole health and morphology in the Rio Grande Leopard frog, Rana berlandieri. We exposed tadpoles to four treatments (1) control: clean water, (2) Roundup®: the active ingredient is glyphosate, the main herbicide used in the United States, (3) antibiotic cocktail, to disrupt the natural microbiome of the tadpoles, and (4) combination: Roundup and antibiotic cocktail. We found that the gut microbial community significantly changed across treatments. Tadpoles in the antibiotic and combination treatments were least active and the smallest compared to the other treatments. Our results provide evidence that the gut microbial communities of tadpoles are sensitive to herbicides and antibiotics, which may have an impact in host phenotype and fitness via altered behavior and growth. This study provides important insights for conservation of amphibians and into the consequences of current agricultural practices.
Abstract
The gut microbiome is important for digestion, host fitness, and defense against pathogens, which provides a tool for host health assessment. Amphibians and their microbiomes are highly susceptible to pollutants including antibiotics. We explored the role of an unmanipulated gut microbiome on tadpole fitness and phenotype by comparing tadpoles of Rana berlandieri in a control group (1) with tadpoles exposed to: (2) Roundup® (glyphosate active ingredient), (3) antibiotic cocktail (enrofloxacin, sulfamethazine, trimethoprim, streptomycin, and penicillin), and (4) a combination of Roundup and antibiotics. Tadpoles in the antibiotic and combination treatments had the smallest dorsal body area and were the least active compared to control and Roundup-exposed tadpoles, which were less active than control tadpoles. The gut microbial community significantly changed across treatments at the alpha, beta, and core bacterial levels. However, we did not find significant differences between the antibiotic- and combination-exposed tadpoles, suggesting that antibiotic alone was enough to suppress growth, change behavior, and alter the gut microbiome composition. Here, we demonstrate that the gut microbial communities of tadpoles are sensitive to environmental pollutants, namely Roundup and antibiotics, which may have consequences for host phenotype and fitness via altered behavior and growth.
... Jechalke et al. (2014) found that FQ antibiotics could remain in the soil for years [49]. The water solubility and flow properties of FQ antibiotics play an important role in increasing their concentrations and mobility in water environments, including surface water [24,35,50,51], groundwater [52], sewage [37,42] and sediment samples [7,35,53]. Chee-Sanford et al. (2009) found that the water solubility of ciprofloxacin and enrofloxacin was 30 g/L and 130 g/L, respectively, which were considered hydrophilic (exceeding 1 g/L) [54]. Yun et al. (2018) found that photodegradation was an important characteristic affecting the existential state of FQ antibiotics in the aquatic environment [55]. ...
Fluoroquinolone antibiotics are widely used in human and veterinary medicine and are ubiquitous in the environment worldwide. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect is reviewed based on in vitro and in vivo experiments referring to many organisms, such as microorganisms, cells, higher plants, and land and aquatic animals. Furthermore, a comparison of the various toxicology mechanisms of fluoroquinolone antibiotic residues on environmental organisms is made. This study identifies gaps in the investigation of the toxic effects of fluoroquinolone antibiotics and mixtures of multiple fluoroquinolone antibiotics on target and nontarget organisms. The study of the process of natural transformation toward drug-resistant bacteria is also recognized as a knowledge gap. This review also details the combined toxicity effect of fluoroquinolone antibiotics and other chemicals on organisms and the adsorption capacity in various environmental matrices, and the scarcity of data on the ecological toxicology evaluation system of fluoroquinolone antibiotics is identified. The present study entails a critical review of the literature providing guidelines for the government to control the discharge of pollutants into the environment and formulate policy coordination. Future study work should focus on developing a standardized research methodology for fluoroquinolone antibiotics to guide enterprises in the design and production of drugs with high environmental biocompatibility.
... The indiscriminate use of such agrochemicals has led to pressure on environmental protection agencies to reduce and mitigate the environmental impacts generated by these compounds, especially with regard to wastewaters discharged into natural water bodies without any treatment (Subasinghe et al. 2009). Agrochemicals are used precisely because they have bioactive properties, which raise serious concerns about the (eco)toxicity of these compounds to non-target organisms (González-Pleiter et al. 2013;Rico et al. 2014). In the past, environmental impact assessments were based on analyses of the toxicological effects of individual chemicals, but under typical environmental conditions, organisms may be exposed to mixtures of chemicals that can present interactions among the constituents, resulting in additive, synergistic, antagonistic, and potentiating effects (Rodea-Palomares et al. 2015;Toumi et al. 2018). ...
Agrochemicals used for treating and preventing aquaculture diseases are usually present in combination with other compounds, and the toxicity resulting from their chemical interactions presents an important reason to assess the ecotoxicity of compound mixtures in view to better understanding the joint action of chemicals and avoiding their environmental impacts. In this study, we evaluated the acute aquatic ecotoxicity of several compounds used in Brazilian fish farming (Oxytetracycline [OXT], Trichlorfon [TRC], and BioFish® [BIO]), both individually and in binary and ternary mixtures. Initial test concentrations were prepared according to the recommended concentrations for aquaculture application, and from these, a geometric dilution series was tested on two important fresh water quality indicator species, the microcrustacean Daphnia magna and the bacterium Aliivibrio fischeri. At the recommended pond application rate, TRC and BIO applied individually showed toxicity to the tested organisms in terms of the lowest-observed-effect concentration (LOEC), and D. magna was always more sensitive than A. fischeri. For the two test organisms, the results obtained with the binary mixtures showed that the TRC and BIO mixture was more toxic than TRC and OXT, which in turn was more toxic than OXT and BIO. The toxicity from all agrochemicals in the ternary mixture was more than that of the agrochemical combinations in the binary mixtures. Given the results presented in this study, it is evident that the mode of action and availability of the tested compounds undergo changes that increase toxicity when they are present in combination, and therefore, aquaculture wastewater treatment should be adopted to ensure decontamination of agrochemical residues.
... In addition, antibiotics carried by unused bait entering natural water bodies would eventually enter the sediment [62]. Thus, although antibiotics are susceptible to photolysis and hydrolysis in water, the decay process of antibiotics is slowed down when they enter the sediment, eventually leading to long-term accumulation of antibiotics [40]. ...
Antibiotics are commonly used to prevent and control diseases in aquaculture. However, long-term/overuse of antibiotics not only leaves residues but results in the development of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Antibiotics, ARB, and ARGs are widespread in aquaculture ecosystems. However, their impacts and interaction mechanisms in biotic and abiotic media remain to be clarified. In this paper, we summarized the detection methods, present status, and transfer mechanisms of antibiotics, ARB, and ARGs in water, sediment, and aquaculture organisms. Currently, the dominant methods of detecting antibiotics, ARB, and ARGs are UPLC−MS/MS, 16S rRNA sequencing, and metagenomics, respectively. Tetracyclines, macrolides, fluoroquinolones, and sulfonamides are most frequently detected in aquaculture. Generally, antibiotic concentrations and ARG abundance in sediment are much higher than those in water. Yet, no obvious patterns in the category of antibiotics or ARB are present in organisms or the environment. The key mechanisms of resistance to antibiotics in bacteria include reducing the cell membrane permeability, enhancing antibiotic efflux, and structural changes in antibiotic target proteins. Moreover, horizontal transfer is a major pathway for ARGs transfer, including conjugation, transformation, transduction, and vesiculation. Identifying, quantifying, and summarizing the interactions and transmission mechanisms of antibiotics, ARGs, and ARB would provide useful information for future disease diagnosis and scientific management in aquaculture.
... However, most fsh stop feeding during an outbreak, thus making the antimicrobial agents inefective. In this study, six commonly used antimicrobial agents, namely amoxicillin, erythromycin, oxytetracycline, doxycycline, enrofoxacin, and sulfamethoxazole-trimethoprim were selected for the antimicrobial susceptibility test, as they are frequently used for the prevention and treatment of bacterial diseases in farmed fsh in Tailand and other Asian countries [52,53]. Of these, amoxicillin, oxytetracycline, enrofoxacin, and sulfamethoxazole-trimethoprim are approved for use in Tailand, while doxycycline is approved for use in China and Bangladesh, and erythromycin is approved for use in Japan, Bangladesh, and Chile [54]. ...
Snakeskin gourami (Trichogaster pectoralis) is a freshwater fsh species that is being increasingly cultivated in Southeast Asia. Te expansion of farms and intensive farming practices has led to the unexplained mortality of snakeskin gourami and tremendous economic losses in many farms. We investigated the unusual mortality of snakeskin gourami at 22 farms in Central Tailand. Te moribund fsh showed darkened skin, erratic swimming, exophthalmos, and haemorrhaging around the eyeballs, with cumulative mortality between 20% and 45%. Our necropsy fndings revealed an enlarged liver and anterior kidney, splenomegaly, haemorrhage in most internal organs, pericarditis, and brain congestion. Histopathology revealed haemorrhaging and congestion of the blood vessels in the liver with in-fltration of lymphocytes, enlarged blood vessels with mononuclear and lymphocyte infltration in the meninges, and cerebral parenchyma were observed. Severe necrotising and suppurative pericarditis with myocardial infarction were found. Epidemiological studies and laboratory diagnosis revealed that Streptococcus agalactiae was predominantly isolated from the moribund fsh. Laboratory investigations of the representative 33 isolates of S. agalactiae using mass spectrometry, multiplex polymerase chain reaction assay, pulse-gel elec-trophoresis, and serotyping suggested that all the isolates were S. agalactiae serotype VII, which is diferent from the serotype III isolated from diseased tilapia in Tailand. An experimental challenge using three representative isolates of S. agalactiae on snakeskin gourami caused clinical signs, gross lesions, and pathological changes, with high mortality exceeding 60%, which is similar to the mortality in most natural infections. Moreover, S. agalactiae was recovered from the spleen, kidneys, and liver of all the challenged fsh. Taken together, this study provides important information that S. agalactiae serotype VII is virulent in snakeskin gourami and can potentially spread among these fsh in fsh farms. Appropriate preventive measures and the control of animal movements should thus be implemented.
... In aquatic environments that receive effluents or lixiviate from agroecosystems and swine, chicken, and cow feedlots, pesticides are likely to be found together with human and veterinary antibiotics 41 . The interaction between pesticides and antibiotics and their effect on enteric bacteria of tadpoles have rarely been studied. ...
The high load of agrochemicals and antibiotics present in agricultural aquatic environments represents a risk for wildlife. Since enteric bacteria, which play a key role in the physiological functioning of their hosts, are sensitive to a wide variety of pollutants, their study allows to evaluate the health of organisms. This study aimed to evaluate the effects of commercial formulations of a glyphosate-based herbicide (GBH) and the antibiotic ciprofloxacin (CIP), individually and in mixture, on the bacterial diversity of the intestinal content of common toad (Rhinella arenarum) tadpoles. The diversity of cultivable fast-growing bacteria with low nutritional requirements was evaluated using classic microbiological tests and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identification. Bacterial diversity varied among treatments. Taxa diversity increased in the GBH-treated group but decreased in the CIP-treated group. Remarkably, Yersinia spp. and Proteus spp. were only found in the GBH-treated group. The prevalence of Klebsiella spp. and Pseudomonas spp. decreased in the intestinal microbiota of the GBH-CIP-treated group. To our knowledge, this is the first report on the alteration of cultivable enteric bacteria of autochthonous tadpoles due to two pollutants of emerging concern. Our results demonstrate that R. arenarum tadpoles can be used as non-conventional model organisms for environmental pollution monitoring. Our preliminary findings would contribute to understanding how the presence of GBH and CIP in freshwaters may represent a threat to wildlife and human health by causing enteric dysbiosis of part of the bacterial community.
... However, this direct effect occurs only at a low frequency in a phytoplankton community because of the low exposure level in natural ecosystems. 104 It is likely that antibiotics affect the composition of phytoplankton communities by inducing changes in species traits and interspecific interactions. 105 Moreover, the indirect effect on the composition of the plankton community would be completely different from the direct effect. ...
Antibiotic pollution has become one of the most challenging environmental issues in aquatic ecosystems, with adverse effects on planktonic organisms that occupy the base of the aquatic food chain. However, research regarding this topic has not been systematically reviewed, especially in terms of community-level responses. In this review, we provide an overview of current antibiotic pollution in aquatic environments worldwide. Then, we summarize recent studies concerning the responses of planktonic communities to antibiotics, ranging from individual- to community-level responses. Studies have shown that extremely high concentrations of antibiotics can directly harm the growth and survival of plankton; however, such concentrations are rarely found in natural freshwater. It is more likely that environmentally relevant concentrations of antibiotics will affect the physiological, morphological, and behavioral characteristics of planktonic organisms; influence interspecific interactions among plankton species via asymmetrical responses in species traits; and thus alter the structure and function of the entire planktonic ecosystem. This review highlights the importance of community analysis in revealing antibiotic toxicity. We also encourage the establishment of the causal relationships between impacts at multiple scales in the future for predicting the community-level consequences of antibiotics based on the currently available individual-level evidence.
... In India, tetracyclines were the most common antibiotics among the six reported antibiotics (cephalexin, doxycycline, enrofloxacin, erythromycin, sulphamethoxazole-trimethoprim, and tetracyclines) applied in different fish farming systems [49]. In Thailand, enrofloxacin was the most common antibiotic, followed by oxytetracycline, amoxicillin, and sulfadiazine, combinedly used with trimethoprim, to control infectious diseases in Tilapia [50]. According to the information provided by representative of Novartis (Bangladesh) Ltd., oxysenthin-20% works against the most common bacterial diseases. ...
Aquaculture is the fastest-growing, most dynamic, and vital food-producing sector compared to other food-producing industries. However, aquaculture production is hampered by a variety of bacterial, viral, fungal, and parasitic diseases. Fish farmers routinely apply various types of aqua-chemicals, particularly antibiotics and pesticides, to reduce the disease burden. Antibiotics and pesticides are widely used to increase fish production around the world, including Bangladesh. Between March 2020 and February 2021, a survey was conducted via face-to-face interviews with fish farmers in the Rajshahi district, Bangladesh, to determine the current status of the use of antibiotics, pesticides, and other aqua-chemicals in the rearing of freshwater finfishes. Nine active antibiotics ingredients belonging to 11 trade names of antibiotics, various pesticides, numerous disinfectants, and aqua-chemicals were found to be used in finfish rearing. The renamycin (active ingredient: oxytetracycline) was most commonly used antibiotics by freshwater finfish farmers in the study areas. In case of pesticides, sumithion and timsen were found to be used mostly by fish farmers. In addition, four distinct probiotics were found to be used in aquaculture in the study areas. The present study revealed several issues related to the use of aqua-drugs in the study areas. For instance, the majority of fish farmers (88%) lacked knowledge in the use of aqua-chemicals and antibiotics, and 81% of fish farmers were unaware about the effective dosages of chemicals in fish farming. Thirty seven percent of fish farmers in the study areas reported the indiscriminate use of chemicals. Furthermore, a considerable proportion of fish farmers (72%) reported ignorance about the residual effects of the aqua-chemicals on the aquatic environment and human health. As a result, this preliminary study suggests that the use of antibiotics, pesticides, and other aqua-chemicals in aquaculture should be strictly monitored and controlled by the responsible authorities of Bangladesh. Moreover, further research needs to be expanded on the detection of residues from aqua-drugs and antibiotics in the aquaculture system, and their consequences on the ecosystem and human health.
... Beckett et al. [54] investigated vegetation and urban woodlands' roles in mitigating air pollution's particulate matter effects. Pani et al. [55] reviewed seasonal air-pollution impacts and Rico et al. [56] conducted a detailed review of various risks involved with cage farming in Thailand. Zanobetti et al. [57] examined the association between ozone and mortality in 20 countries. ...
Air pollution has been an vital issue throughout the 21st century, and has also significantly impacted the agricultural community, especially farmers and yield crops. This work aims to review air-pollution research to understand its impacts on the agricultural community and yield crops, specifically in developing countries, such as India. The present work highlights various aspects of agricultural damage caused by the impacts of air pollution. Furthermore, in the undertaken study, a rigorous and detailed discussion of state-wise and city-wise yield-crop losses caused by air pollution in India and its impacts has been performed. To represent air-pollution impacts, the color-coding-based AQI (Air Quality Index) risk-classification metrics have been used to represent AQI variations in India’s agrarian states and cities. Finally, recent impacts of air pollution concerning AQI variations for May 2019 to February 2020, Seasonal AQI variations, impacts of PM2.5, and PM10 in various agrarian states and India cities are presented using various tabular and graphical representations.
... Due to the intensive use of enrofloxacin in aquaculture sector, enrofloxacin was also found in fishery products that are sold in many countries across the globe ( Kang et al., 2017 ). Enrofloxacin has also been detected in Tha Chin river, Thailand ( Rico et al., 2014 ), Mekong Delta, Vietnam ( Chau et al., 2015 ) and Yellow sea of China . Enrofloxacin can be metabolized into ciprofloxacin which is also a quinolone antibiotic ( Trouchon and Lefebvre, 2016 ). ...
MXenes, a new family of two-dimensional transition metal carbides or nitrides, have attracted tremendous attention for various applications due to their unique properties such as good electrical conductivity, hydrophilicity, and ion intercalability. In this work, Ti3C2 MXene, or MX, is converted to MX-TiO2 composites using a simple and rapid microwave hydrothermal treatment in HCl/NaCl mixture solution that induces formation of fine TiO2 particles on the MX parent structure and imparts photocatalytic activity to the resulting MX-TiO2 composites. The composites were used for enrofloxacin (ENR), a frequently found contaminating antibiotic, removal from water. The relative amount of the MX and TiO2 can be controlled by controlling the hydrothermal temperature resulting in composites with tunable adsorption/photocatalytic properties. NaCl addition was found to play important role as composites synthesized without NaCl could not adsorb enrofloxacin well. Adding NaCl into the hydrothermal treatment causes sodium ions to be simultaneously intercalated into the composite structure, improving ENR adsorption greatly from 1 to 6 mg ENR/g composite. It also slows down the MX to TiO2 conversion leading to a smaller and more uniform distribution of TiO2 particles on the structure. MX-TiO2/NaCl composites, which have sodium intercalated in their structures, showed both higher ENR adsorption and photocatalytic activity than composites without NaCl despite the latter having higher TiO2 content. Adsorbed ENR on the composites can be efficiently degraded by free radicals generated from the photoexcited TiO2 particles, leading to high photocatalytic degradation efficiency. This demonstrates the synergetic effect between adsorption and photocatalytic degradation of the synthesized compounds.
... However, many studies have shown that antibiotics cannot be wholly metabolized in organisms, even can accumulate in the tissues and muscles of fish and other aquatic products (Rico et al., 2014;Chen et al., 2018Chen et al., , 2020Liu et al., 2017aLiu et al., , 2017b, and aquaculture wastewater treatment facilities cannot altogether remove them (Gorito et al., 2018;Huang et al., 2019). Additionally, aquaculture wastewater containing antibiotics is directly or indirectly discharged into the receiving environment, which may pose various potential risks, even induce the emergence of antibiotic-resistant microbes, and the spread of antibiotic resistance genes (ARGs) (Asiri et al., 2022;Silva et al., 2021;Asiri and Chu, 2020;Xu et al., 2020;Wu et al., 2019). ...
The recirculating aquaculture system (RAS) has attracted much attention in China as a way to rapidly transform and upgrade aquaculture ponds to realize zero-emissions of pollutants in aquaculture tail water. Tail water purification ponds (TWPPs) play an important role in the treatment of aquaculture wastewater. However, until now, there have been few reports on the occurrence of antibiotics in RAS and the removal of antibiotics from the TWPPs of RAS. Therefore, this study focused on the occurrence of antibiotics in a typical ecological RAS. For comparison, the same measurements were simultaneously carried out in nearby open aquaculture ponds and rivers. The pollution level and spatial distribution of antibiotics in the RAS and the removal of antibiotics in the TWPPs were explored. The results showed that (1) eleven and twelve antibiotics were detected in water and sediment samples in the RAS, respectively, but no antibiotics were found in fish muscles and feed. Erythromycin (ERY), lincomycin (LIN), and ciprofloxacin (CFX) were the three main types of antibiotics found in water and sediment samples. (2) The TWPPs of the RAS can effectively remove antibiotics in aquaculture water. The antibiotic concentration in recirculating aquaculture ponds of the RAS was as high as 180 ng/L. After treatments in the TWPPs, the antibiotic concentration of aquaculture water decreased to 81.6 ng/L (3) The antibiotic concentrations in recirculating aquaculture ponds (25.2–180 ng/L) were lower than those in the nearby open aquaculture ponds (126–267.3 ng/L), and the concentration of antibiotics in the sediments of recirculating aquaculture ponds was up to 22.9 ng/g, while that in TWPPs was as high as 56.1 ng/g. In conclusion, the antibiotic residues in the RAS were low after antibiotics were banned in feed in China, and the removal of antibiotics in the TWPPs was more pronounced. Furthermore, cross-contamination was found between the RAS, surrounding open aquaculture ponds and the river, and the water supply of the RAS was likely to be the main contributor of antibiotics in the aquaculture environments. This study can help the government formulate discharge standards for antibiotics in aquaculture and also provide a reference for the transformation and upgrading of aquaculture ponds to achieve a zero-emission aquaculture mode.
... Due to the lack of data on the biotoxic effects of antibiotic pollutants on benthic organisms in sediments, this study refers to the ecological risk assessment method of entropy value, and converts the contents of pollutants detected in sediments into the contents of pollutants in pore water, and then through the aquatic Biotoxicity effect data to evaluate its risk. This method can make up for the lack of ecological risk assessment methods for pollutants in sediments, and has certain reliability (Rico et al., 2014;Zhao et al., 2010). To convert the pollutant content (Cs) in the sediment to the pollutant content (Cp) in the pore water, the formula is as follows: ...
The hydrodynamics in the diverging area become complicated because of the basin hydrological conditions, making the distribution of antibiotics largely uncertain and thus bringing uncertain ecological risks of antibiotics. Through field sampling, experiments and numerical simulations, the distribution of antibiotics, its responses to hydrological conditions were studied. Antibiotics in the bifurcated river sediments was mainly distributed in the branch mouth. The hydrodynamic regions were affected by the hydrological frequency. Notably, the center of the low-velocity area moved upstream and gradually expands to the entire tributary as the hydrological frequency shifted from high to low. ENRO (enrofloxacin) and OFC (ofloxacin) were the key hazardous antibiotics affecting the ecological health in the diverging area, and their concentrations are mainly affected by sediment particle size (D < 0.15 mm) and oxygen content. The ecological risk of antibiotics in the diverging area were gradually decreased with the increase of the distance from the central area. The water physical and chemical properties, altered by the river basin hydrological conditions, play an important role in influencing the distribution of antibiotic concentrations, and ultimately posing great threat to aquatic ecosystem. The research provides a scientific basis for antibiotic risk control in the diverging area under different hydrological conditions.
... One more important measure is using of biocides (disinfectants). The most commonly used disinfectants are potassium permanganate, iodine solutions, sodium hypochlorite, phenol, quaternary ammonium compounds (QACs), glutaraldehyde (GA) and formaldehyde; however, overdoses of these compounds are highly toxic to the aquatic organisms (Rico et al., 2014). GA was formulated in conjunction with QACs to achieve a synergistic effect and obtain faster action and higher activity over a wider spectrum (Jeffrey, 1995). ...
This study investigated the prevalence of Enterococcus faecalis amongst cultured
Oreochromis niloticus and Mugil cephalus and evaluated the potential use of oregano essential oil (OEO) and glutaraldehyde (GA)-quaternary ammonium compounds (QACs)
combination for its possible control in the light of levels used in Egyptian aquaculture. The total prevalence of E. faecalis was 50.5%, whereas O. niloticus was the most
affected species 59%. Molecular typing revealed that the retrieved isolates shared
a common ancestor and showed 99.86% genetic similarity to E. faecalis type strain
(CAU: 182). The in vitro assays revealed that the measurement techniques showed
a highly significant (p ≤ 0.01) reduction in E. faecalis count at 1250 mg L−1 OEO with
complete inhibition at 2500 mg L−1. The techniques have a strong positive correlation (p ≤ 0.01) with a slope of regression (R2 = 0.872), and their compatibility reached
high levels with the area under the curve (AUC) at different wavelengths. Of interest,
GA and QACs had LC50 of 2.19 and 5.16 mg L−1, respectively, in red tilapia. Moreover,
these chemicals had a synergistic effect, with the best bactericidal activity at T1 conc.
(0.5 mg GA + 1.2 mg QACs) after 10 min of exposure in both fresh and marine water.
Organic matter delayed the activity of the disinfectant and increase the exposure
time to 30 min in marine water. Overall, OEO, GA and QACs could be considered as
potential surrogates for antibiotic usage for possible control of E. faecalis.
... Antibiotics' use, environmental fate, and ecological dangers in a tilapia cage, the antibiotics oxytetracycline (OTC) and enrofloxacin (ENR) were tested utilizing river water and sediment samples. Sediment concentrations up to 6908 g/kg d.w. for OTC and 2339 g/kg d.w. for ENR were found insignificant short-term risks for primary producers and invertebrates (Rico et al. 2014). Furthermore, the ecological risk of antibiotics ENR and ciprofloxacin (CIP) in a pangasius catfish in a farm in Vietnam, where the Chlorella sp. had EC50 values of 111,000 and 23,000 g L (À1) for ENR and CIP, respectively, and 69,000 and 71,000 g L (À1) for M. ...
Aquaculture is one of the fastest-growing industries in the world, and it primarily helps to boost global production. The possibility of cultured fish demonstrating their genetic capacity for growth and reproduction major crucial factor determined by nutrition. Because of the limitation on the use of various antibiotics, as well as their cost-effectiveness, natural feed additives are an external source of aquaculture output. The enhancement in cost scarcity of supplies of fish feed has necessitated more study into replacements. Many researchers have recently demonstrated the benefits of medicinal herbs as feed additives. Even consumers are concerned about using antibiotics instead of natural feed additives to increase aquaculture quality. The determination of feed additives is to suppress pathogenic bacteria, improve growth, stimulate the immune system, and assure water purity. Essential oils, essential fatty acids, probiotics and prebiotics, synbiotics, and exogenous enzymes were all used in several types of feed additives. These additives were praised for their unique medical capabilities as well as their eco-friendly digestive system metabolisms. However, utilizing crops in feeds increases the risk of fungus and mycotoxins contamination, as well as the incidence of mycotoxicosis in fish. Because mycotoxicosis causes decreased bodyweight, growth impairment, and greater rates of disease and mortality in fish, this could reduce aquaculture productivity. This chapter highlights the cumulative research findings on various feed additives, and aquaculture production quality and mycotoxins impair the animal immune systems.
... Besides pathogens, organic and inorganic compounds, sludge is contaminated by antibiotics [6] that are widely used in human medicine and excreted into the domestic wastewater stream and then the WWTP. As a consequence of the direct application of sludge, antibiotics were found in soil, sediment, surface, and underground water [7]. Antibiotics emergence contributes to antibioresistance dissemination in the microbial communities including pathogens [8,9]. ...
This study investigated the fate of antibiotics during composting and its relationship with organic matter fractionation. Sludge was spiked with roxithromycin (ROX), chlortetracycline (CTC), oxytetracycline (OTC), and ciprofloxacin (CIP), at 3 different levels. Accelerated solvent extraction (ASE) and liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were used for the extraction and the quantification of antibiotics. Sludge composting effectively removed parent compounds (p<0.01) such as ROX, CTC, and OTC (52-87, 69-95, and 100% respectively), while CIP persisted in the final compost (p>0.05). The thermophilic stage was responsible for ROX removal, and the maturation stage was more implicated in removing CTC and OTC. Chemical accessibility and 3D fluorescence showed that high level of antibiotics affected the behavior of organic fractions. ROX removal was more associated with decreasing the most accessible fractions. The removals of CTC and OTC was more associated with the depletion of the complex organic matter. The observed results were confirmed by PCA and dendrograms analysis that confirmed the relationship between antibiotics removal and the evolution of organic pools. On the other hand, germination test indicated that cress and turnip were more sensitive to high antibiotic concentration. These results have been explored for the first time and they are recommended for controlling antibiotic removal based on organic matter fractionation.
... Global antibiotic consumption rapidly increased 65% between 2000 and 2015 [1]. Antibiotic residue can enter aquatic ecosystems through several major pathways, including the dissolution of feed pellets in fish farming [2], excretion of residual antibiotics from cultured organisms [3] and humans [4], the discharge of waste from hospitals and pharmaceutical plants [5] (Figure 1). Within the aquatic environment, antibiotics can result in the spread of antibiotic-resistant bacteria, which is creating a global environmental crisis. ...
Antibiotic pollution is an emerging environmental challenge. Residual antibiotics from various sources, including municipal and industrial wastewater, sewage discharges, and agricultural runoff, are continuously released into freshwater environments, turning them into reservoirs that contribute to the development and spread of antibiotic resistance. Thus, it is essential to understand the impacts of antibiotic residues on aquatic organisms, especially microalgae and cyanobacteria, due to their crucial roles as primary producers in the ecosystem. This review summarizes the effects of antibiotics on major biological processes in freshwater microalgae and cyanobacteria, including photosynthesis, oxidative stress, and the metabolism of macromolecules. Their adaptive mechanisms to antibiotics exposure, such as biodegradation, bioadsorption, and bioaccumulation, are also discussed. Moreover, this review highlights the important factors affecting the antibiotic removal pathways by these organisms, which will promote the use of microalgae-based technology for the removal of antibiotics. Finally, we offer some perspectives on the opportunities for further studies and applications.
... The anthropogenic impact on sediments is frequently investigated to evaluate the health of aquatic environments (Feiler et al., 2013). As part of monitoring campaigns, contaminations by antibiotics (Rico et al., 2014) or pesticides (Carazo-Rojas et al., 2018) were detected in sediments. While sediment characteristics were not within the authors´focus, these important parameters are determining the adsorption/desorption behavior of the investigated compounds. ...
Artificial sediment used in studies according to OECD 218/219 (Sediment Water Chironomid Toxicity Test Using Spiked Sediment/Water) does not necessarily mirror the characteristics of natural sediments. To investigate the influence of sediment characteristics on the spatial-temporal behaviors of bixafen (KfOM = 2244 mL/g), fluopyram (KfOM = 162 mL/g) and N,N-dimethylsulfamide (KfOM ≈ 0 mL/g), experiments according to OECD 218/219 with two contrasting natural sediments were conducted. The silt loam sediment provided a high content of organic matter (OM) (13.1%), while the OM (0.45%) of the sandy sediment was low. Diffusion into (OECD 219) or out (OECD 218) of the sediment was dependent on the extent of adsorption, which is linked to the model compounds ́ adsorption affinities and the sediments ́ OM. Consequently, N,N-dimethylsulfamide showed unhindered mobility in each experimental set up, while the high adsorption affinities of fluopyram and bixafen limited the diffusion in the respective sediments. Therefore, in experiments with the silt loam sediment, both compounds revealed a limited mobility and either accumulated in the top 5 mm of the sediment (OECD 219) or remained homogenously distributed over the sediment depth (OECD 218). A greater mobility was observed within the sandy sediment.The influence of OM as found in a study using artificial sediment could be confirmed. Moreover, the applicability of a TOXSWA model was reassured to predict the measured concentrations at different sediment depths. TOXSWA is used in the regulatory exposure assessment to simulate the behavior of pesticides in surface waters. Calibration of three driving input parameters by inverse modelling (diffusion-, adsorption coefficient and OM) revealed no potential for improvement. The core sampling technique used and the model may contribute to a more realistic determination of concentration to which the Chironomid larvae are exposed to. This applies to water sediment test systems where the test organisms do not evenly inhabit the sediment.
... At present, there are few studies on antibiotics in sediments, and they mainly focus on water bodies (Ding et al., 2017;Hossain et al., 2017;Wang et al., 2017). Due to the lack of biotoxic effect data of antibiotics in sediments, this study converted the content of pollutants detected in sediments into the content of contaminants in pore water by referring to the entropy ecological risk assessment method of Rico and Zhao, and then evaluated the risk based on the toxicity effect data of aquatic organisms (Rico et al., 2014;Zhao et al., 2010). The risk assessment for sediment was using the following equation ( where PNEC water is the predicted invisible effect content of aquatic organisms in water; C pore is the concentration of antibiotics in pore water equivalent to MEC, ng/L; C s. i is the content of antibiotics in sediments, ng/g (dw); %TOC is the total organic carbon content of the sediment, %; Koc is the normalized sediment/water partition coefficient of organic carbon of antibiotics, L/kg; K ow is the octanol-water partition coefficient. ...
Antibiotics have been widely used to prevent or treat bacterial infections in aquaculture in the past decades. However, large proportions of these compounds are excreted unchanged in feces and urine of animals, given incomplete metabolism, leading to the residual of unmetabolized compounds, and posing a potential risk to the environment. This study investigated the occurrence and distribution of seven antibiotics in surface water, sediments, fish muscle, and fish feed by high-performance liquid chromatography from the aquaculture areas in Guilin, South of China. The highest concentrations of the target antibiotics in water, sediment, fish muscle, and fish feed were 2047.53 ng/L, 13.32 μg/kg, 35.90 μg/kg, and 2203.97 μg/kg, respectively. In contrast, the most abundant antibiotic was enrofloxacin (ENR), followed by ofloxacin (OFL), sulfadimidine (SMZ), and ciprofloxacin (CIP). In this work, the concentrations of antibiotics were lower than those in other breeding areas. Correlation analyses showed significant relationships between sulfadiazine (SDZ) and TP, TN, and CODCr in water. In sediment, the release of SDZ was significantly related to TN, TP, and organic matter. The risk quotient (RQ) results revealed that sulfamethoxazole (SMX), CIP, and ENR were at high risk to microorganisms in water; while, SMX and NOR were at high risk in sediments. The result from the estimated daily intakes (health risk quotient, HQ < 1) suggested that the antibiotics might not pose a risk to human health by dietary exposure assessment; however, sediments may become an accumulation reservoir of antibiotics and cause secondary pollution, of which the local management should raise awareness.
... Thus, they are proposed to subsequently be disposed into the environment by run-off water, sedimentation of feces, or uneaten feed pellets that can then be eaten by local fish or invertebrates [21][22][23][24][25]. The unconstrained use of antimicrobials in aquaculture can therefore transmit antibiotic-resistant bacteria, which are commonly transferred through R plasmids, with fish bacteria acting as intermediates [18,20,22,[26][27][28][29][30][31]. ...
Background and aim:
The emergence of antibiotic-resistant bacterial pathogens has been increasingly reported, which has resulted in a decreasing ability to treat bacterial infections. Therefore, this study investigated the presence of Aeromonas spp., including its antibiotic resistance in various fish samples, Oreochromis spp., Clarias gariepinus, and Pangasius hypophthalmus, obtained from Kelantan and Terengganu, Malaysia.
Materials and methods:
In this study, 221 fish samples, of which 108 (Oreochromis spp., n=38; C. gariepinus, n=35; and P. hypophthalmus, n=35) were from Kelantan and 113 (Oreochromis spp., n=38; C. gariepinus, n=35; and P. hypophthalmus, n=40) were from Terengganu, were caught using cast nets. Then, samples from their kidneys were cultured on a Rimler Shott agar to isolate Aeromonas spp. Polymerase chain reaction (PCR) was used to confirm this isolation using specific gene primers for species identification. Subsequently, the isolates were tested for their sensitivity to 14 antibiotics using the Kirby-Bauer method, after which the PCR was conducted again to detect resistance genes: sul1, strA-strB, aadA, bla TEM, bla SHV, tetA-tetE, and tetM.
Results:
From the results, 61 isolates were identified as being from the genus Aeromonas using PCR, of which 28 were Aeromonas jandaei, 19 were Aeromonas veronii, seven were Aeromonas hydrophila, and seven were Aeromonas sobria. Moreover, 8, 12, and 8 of A. jandaei; 4, 3, and 12 of A. veronii; 6, 0, and 1 of A. hydrophila; and 3, 3, and 1 of A. sobria were obtained from Oreochromis spp., C. gariepinus, and P. hypophthalmus, respectively. In addition, the isolates showed the highest level of resistance to ampicillin (100%), followed by streptomycin (59.0%), each kanamycin and nalidixic acid (41.0%), neomycin (36.1%), tetracycline (19.7%), sulfamethoxazole (14.8%), and oxytetracycline (13.1%). Resistance to gentamicin and ciprofloxacin both had the same percentage (9.8%), whereas isolates showed the lowest resistance to norfloxacin (8.2%) and doxycycline (1.6%). Notably, all Aeromonas isolates were susceptible to chloramphenicol and nitrofurantoin. Results also revealed that the multiple antibiotic resistances index of the isolates ranged from 0.07 to 0.64, suggesting that the farmed fish in these areas were introduced to the logged antibiotics indiscriminately and constantly during their cultivation stages. Results also revealed that the sul1 gene was detected in 19.7% of the Aeromonas isolates, whereas the tetracycline resistance genes, tetA and tetE, were detected in 27.9% and 4.9% of the isolates, respectively. However, β-lactam resistance genes, bla TEM and bla SHV, were found in 44.3% and 13.1% of Aeromonas isolates, respectively, whereas strA-strB and aadA genes were found in 3.3% and 13.1% of the isolates, respectively.
Conclusion:
This study, therefore, calls for continuous surveillance of antibiotic-resistant Aeromonas spp. in cultured freshwater fish to aid disease management and better understand their implications to public health.
... The presence and/or persistence of tetracycline resistance is suspected to be related to the use of tetracyclines in aquaculture (Thi Kim Chi et al., 2017). However, similar antimicrobial use is reported in aquaculture in Thailand and Viet Nam, but resistance to tetracycline amongst human ST283 isolates from Thailand disappeared after 2012 (Rico et al., 2014). This loss of tetracycline resistance after 2012 was also seen in human ST283 isolates from Lao People's Democratic Republic and Singapore (Barkham et al., 2019). ...
In Singapore during 2015, Group B Streptococcus (GBS) sequence type 283 (ST283) caused the only reported foodborne outbreak of invasive GBS disease. Over 20 percent of cases were healthy adults without comorbidities, which is unusual for GBS. The outbreak was linked to the consumption of raw freshwater fish. Subsequent investigations found that ST283 GBS has been common among GBS causing disease in humans and in tilapia across Southeast Asia for at least 20 years whereas it was almost non-existent outside this region. Given the novelty of the outbreak, this risk profile consolidates the current knowledge to identify data gaps about GBS ST283 along the freshwater fish supply chain in Southeast Asia.
Although GBS fish infection can present with few clinical signs of disease, outbreaks of GBS in high intensity tilapia aquaculture can result in severe infection with mortalities of up to 80 percent. These outbreaks are largely undocumented but likely have a wide effect on aquaculture, given its economic and social importance across Southeast Asia.
There is also a lack of data on patterns of fish consumption, including frequency, amount, preparation and consumer demographics. Nevertheless, consumption of non-heat-treated freshwater fish is common in Southeast Asia. Given the multitude of data gaps, the risk posed by GBS ST283 from consumption of freshwater fish remains highly uncertain. Potential risk management options start with the application of good aquaculture practices and good food safety measures throughout the supply chain.
Aeromonas hydrophila is a zoonotic, important primary fish pathogen in many economic fish species. Aeromonas acquires and exchanges antimicrobial resistance genes (ARG) and has been widely studied as a potential reservoir of ARGs. This research aims to observe the impact of antibiotics used through the role of Aeromonas hydrophila as a pathogenic bacteria in aquaculture. The tested antibiotics are based on the Minister of Marine Affairs and Fisheries No. 1/2019 Decree, namely tetracycline, oxytetracycline, and enrofloxacin, which the Indonesian government allows to be used in aquaculture. Random sampling was conducted using four to five fishes per farm in West Java, namely Bogor (17 farms) and Sukabumi (10 farms), Central Java at Banyumas (38 farms), and Magelang (25 farms). The test method used is CLSI-2020, an Antimicrobial Sensitivity Test disk diffusion with standard bacteria ATCC Escherichia coli 25922. The results show that A. hydrophila is resistant to tetracycline by 15,06% and oxytetracycline by 54,54%. However, A. hydrophila is sensitive to enrofloxacin by 84%. The aquatic environment acts as a reservoir for antibiotic-resistant A. hydrophila and emphasizes the importance of prudent antimicrobial use and timely AMR surveillance in aquaculture.
This study aimed to investigate the pulmonate snail species in the vicinity of the cercarial dermatitis outbreak area in southern Thailand. In 2020, an outbreak of cercarial dermatitis was reported in Chana district, Songkhla Province, caused by the ruminant schistosome Schistosoma indicum and its snail intermediate host Indoplanorbis exustus. In the present study, 1,175 pulmonate snails were collected between October 2021 and October 2022 from five provinces covering 34 locations in southern Thailand. Seven pul-monate snail species were identified based on shell morphology, including Amerianna carinata, Gyraulus bakeri, G. convexiusculus, G. hubendicki, Physella acuta, Indoplanorbis exustus, and Radix rubiginosa. Among these snails, eight species, and five types of cercariae were identified, viz. type (i) Echinostome cercariae consisted of Echinoparyphium recurvatum, Echinostoma spiniferum, and E. revolutum, type (ii) Brevifurcate-apharyngeate cercariae consisted of Schistosoma indicum and S. spindale, type (iii) Bre-vifurcate-pharyngeate-clinostomatoid-cercariae was represented by Clinostomum giganticum, type (iv) Longifurcate-pharyngeate cercariae (strigea cercaria) was Diplostomum baeri eucaliae, and type (v) Ophthalmoxiphidiocercaria. Among the seven pulmonated snail species, three were found to be infected, viz. G. convexiusculus, I. exustus, and R. rubiginosa, with infection rates of 1.14% (2/176), 0.25% (2/802), and 4.02% (7/174), respectively.
The degradation kinetics of Sodium dodecylbenzene sulfonate (SDBS) surfactant in the UV/chlorine process was comprehensively investigated, and the formation of chlorinated disinfection by-products (Cl-DBPs) were determined. Results showed that the degradation of SDBS by UV, chlorine and UV/chlorine all followed pseudo-first-order kinetics. The rate constant by UV/chlorine in ultrapure water was approximately 3 times higher than the sum of those by UV and chlorine, and decreased from 0.297 to 0.063 min-1 with pH increasing from 5.0 to 9.0. Water matrices such as NO3-, HCO3- and natural organic matter (NOM) inhibited the degradation efficiency to a certain extent. The second-order rate constant of SDBS with HO• was determined as 2.84 × 109 M-1 s-1. Through using different probes, the main contributors to SDBS degradation were found to be UV, HO• and reactive chlorine species (RCS). Meanwhile, 64.0 μg L-1 trichloromethane (TCM) and 8.7 μg L-1 chloral hydrate (CH) were simultaneously formed within 30 min of UV/chlorine treatment. The concentration of total organic chlorine (TOCl) (424.0 μg L-1) was obviously higher than those of TCM and CH. In addition, 414 unknown by-products formed during UV/chlorine treatment were detected by mass spectrometry at a high confidence level, including 64 monochloro-DBPs and 2 dichloro-DBPs. Although UV/chlorine process accelerated SDBS degradation, the associated DBP formation deserves enough attention.
Fish transportation is a regular farming and experimental practice that mainly results in stress conditions that may extend to induce a high mortality rate. In the present experimental simulation, Oreochromis niloticus were transported for 2 h and maintained for another 6 h in transportation containers to assess the effect of tranquilization with tricaine methanesulfonate (MS-222) and/or the addition of iodine on mortality rate and restoring the normal physiological functions. Experimental fish were divided into four groups: group 1 (control) was transported in farm water without MS-222 or iodine, group (2) was transported in farm water supplemented with 40 mg/L of MS-222, fish in group (3) were transported in farm water supplemented with 40 mg/L of MS-222 + 10 ppm iodine, and fish in group (4) were transported in farm water containing 10 ppm iodine. Blood samples were collected for the determination of serum cortisol and glucose, while skin mucus was collected for assaying lysozyme, peroxidase and antibacterial activity; cumulative mortality rate; and food reflexes which were assessed at 0 h, 1 h, 6 h, 48 h, 7 days and 14 days post 2 h transportation. The results indicated that fish tranquilization with MS-222 and/or treatment with iodine mitigated the stress condition associated with transportation and accelerate restoration of the normal physiological and immunological status. So, it was recommended to use the MS-222 as a tranquillizer together with iodine as an antiseptic during transportation of O. niloticus.
Citation: Haifa-Haryani, W.O.; Amatul-Samahah, M.A.; Azzam-Sayuti, M.; Chin, Y.K.; Zamri-Saad, M.; Natrah, I.; Amal, M.N.A.; Satyantini, W.H.; Ina-Salwany, M.Y. Prevalence, Antibiotics Resistance and Plasmid Profiling of Vibrio spp.
Exposure to antibiotics can result in not only ecotoxicity on aquatic organisms but also the development of antibiotic resistance. In the study, the ecotoxicity data and minimum inhibitory concentrations of the antibiotics were screened to derive predicted no-effect concentrations of ecological (PNECeco) and resistance development risks (PNECres) for 36 antibiotics in fresh surface waters of China. The derived PNECeco and PNECres values were ranged from 0.00175 to 2351 μg/L and 0.037–50 μg/L, respectively. Antibiotic ecological and resistance development risks were geographically widespread, especially in the Yongding River, Daqing River, and Ziya River basins of China. Based on the risk quotients, 11 and 14 of 36 target antibiotics were at high ecological risks and high resistance development risks in at least one basin, respectively. The higher tiered assessments provided more detailed risk descriptions by probability values and β-lactams (penicillin and amoxicillin) were present at the highest levels for ecological and resistance development risks. Although there was uncertainty based on the limited data and existing methods, this study can indicate the overall situation of the existing risk levels and provide essential insights and data supporting antibiotic management.
Antibiotics are emerging contaminants in aquatic environments which pose serious risks to the ecological environment and human health. Advanced oxidation processes (AOPs) based on ultraviolet (UV) light have good application prospects for antibiotic degradation. As new and developing UV-AOPs, UV/chlorine and derived UV/chloramine processes have attracted increasing attention due to the production of highly reactive radicals (e.g., hydroxyl radical, reactive chlorine species, and reactive nitrogen species) and also because they can provide long-lasting disinfection. In this review, the main reaction pathways of radicals formed during the UV/chlor (am)ine process are proposed. The degradation efficiency, influencing factors, generation of disinfection by-products (DBPs), and changes in toxicity that occur during antibiotic degradation by UV/chlor (am)ine are reviewed. Based on the statistics and analysis of published results, the effects caused by energy consumption, defined as electrical energy per order (EE/O), increase in the following order: UV/chlorine < UV/peroxydisulfate (PDS)< UV/H2O2 < UV/persulfate (PS) < 265 nm and 285 nm UV-LED/chlorine (EE/O). Some inherent problems that affect the UV/chlor (am)ine processes and prospects for future research are proposed. The use of UV/chlor (am)ine AOPs is a rich field of research and has promising future applications, and this review provides a theoretical basis for that.
The use of chemicals, biologicals and veterinary medicinal products (VMPs) helps in healthy and sustainable fish production. Information on the use of these products is essential for assessing farming practices, potential human health and environmental risks. A questionnaire‐based nationwide survey covering aquaculture farms (n = 2936) producing carps, tilapia, pangasius and rainbow trout in freshwater and shrimp in brackishwater estimated the use of 52 different types of inputs which included disinfectants (597 g t−1), probiotics (2.28 kg t−1), environmental modifiers (22.82 kg t−1), nutritional supplements (1.96 kg t−1), natural anti‐infective agents (293 g t−1), herbicide and piscicides (844 g t−1), antibiotics (2 mg PCU−1), antifungal (4 mg PCU−1), and antiparasitic (14 mg PCU−1) agents. The bulk of these inputs was used for soil and water quality improvement and had low environmental and human safety concerns. The multivariate analysis revealed significant variation in the frequency and quantity of compounds use among farm groups. Redundancy analysis revealed a significant association between the number of products used and stocking density. The survey also showed a considerable influence of education and farming experience on the usage pattern of aquaculture inputs. Results of the study indicated greater reliance of farmers on the use of disinfectants for biosecurity, nutritional supplements for enhanced growth and environmental modifiers for maintaining soil and water quality in culture systems. Though there was no use of restricted antibiotics and antiparasitic agents, the development and implementation of standard regulatory guidelines are essential for safe and effective use of inputs for sustainable aquaculture.
Aquaculture is remarkably one of the most promising industries among the food-producing industries in the world. Aquaculture production as well as fish consumption per capita have been dramatically increasing over the past two decades. Shifting of culture method from semi-intensive to intensive technique and applying of antibiotics to control the disease outbreak are the major factors for the increasing trend of aquaculture production. Antibiotics are usually present at subtherapeutic levels in the aquaculture environment, which increases the selective pressure to the resistant bacteria and stimulates resistant gene transfer in the aquatic environment. It is now widely documented that antibiotic resistance genes and resistant bacteria are transported from the aquatic environment to the terrestrial environment and may pose adverse effects on human and animal health. However, data related to antibiotic usage and bacterial resistance in aquaculture is very limited or even absent in major aquaculture-producing countries. In particular, residual levels of antibiotics in fish and shellfish are not well documented. Recently, some of the countries have already decided the maximum residue levels (MRLs) of antibiotics in fish muscle or skin; however, many antibiotics are yet not to be decided. Therefore, an urgent universal effort needs to be taken to monitor antibiotic concentration and resistant bacteria particularly multiple antibiotic-resistant bacteria and to assess the associated risks in aquaculture. Finally, we suggest to take an initiative to make a uniform antibiotic registration process, to establish the MRLs for fish/shrimp and to ensure the use of only aquaculture antibiotics in fish and shellfish farming globally.
Freshwater aquaculture is an important source, reservoir and hotpot of antibiotics and ARGs, but the overall characteristics of antibiotics and ARGs in freshwater aquaculture on national scale is still unknown. This article is the first to comprehensively reveal the occurrence, distribution, trend and risk of antibiotics and antibiotic resistance genes (ARGs) in Chinese freshwater ponds through a meta-analysis. Results showed that forty-four antibiotics occurred in freshwater aquaculture ponds in China and trimethoprim, enoxacin, monensin, clarithromycin, roxithromycin erythromycin-H2O had the highest detection rates (>50%). Antibiotic concentrations in aquaculture ponds were related to the aquaculture area and aquaculture production at the provincial scale, and the pollution levels in Jiangsu and Tianjin were higher than that in other investigated provinces. Polymerase chain reaction results revealed that sul1 and sul2 were the most reported ARGs, and tetracycline resistance genes had the most reported subtype in aquaculture ponds. However, metagenomic results showed multidrug resistance genes were the predominant genes, followed by aminoglycoside, beta-lactam and bacitracin resistance genes. Meta-analysis showed that the significantly positive correlations existed in most antibiotics and their ARGs, e.g. ∑SAs with sul2 and sul3; ∑TCs with ∑tet, tetA and tetO. Ecological risk assessment showed that 18 antibiotics in 27 evaluated antibiotics had medium-high risk levels in aquaculture waters. Antibiotic restriction programs have reduced the pollution level and ecological risks of target antibiotics in China to some extent. In order to pursuit the ecological and sustainable aquaculture, the future priorities and research direction on antibiotics and ARGs in freshwater aquaculture were finally pointed out.
The overuse of antibiotics and their disposal without processing are leading the environment and its inhabitants towards a serious health emergency. There is abundance of diverse antibiotic resistance genes and bacteria in environment, which demands immediate attention for the effective removal of antibiotics. There are physical and chemical methods for removal, but the generation of toxic byproducts has directed the efforts towards bioremediation for eco-friendly and sustainable elimination of antibiotics from the environment. Various effective and reliable bioremediation approaches have been used, but still antibiotic residues pose a major global threat. Recent developments in molecular and synthetic biology might offer better solution for engineering of microbe–metabolite biodevices and development of novel strains endowed with desirable properties. This review summarizes the impact of antibiotics on environment, mechanisms of resistance development, and different bioremediation approaches.
Antibiotic-contaminated water, particularly oxytetracycline (OTC), which is widely used in aquaculture, can threaten human health through the ingestion of edible aquatic organisms. The objective of this study was to develop novel and cost-effective calcium peroxide nanoparticles (nCaO2), synthesized using flue gas desulfurization (FGD) gypsum for improving water quality and OTC removal. The nCaO2-FGD was synthesized using a 1:7 (FGD:H2O2) mixture. The results showed that nCaO2-FGD had spherical particles with diameters of 20–60 nm. The dissolved oxygen production in water by nCaO2-FGD significantly increased, with an oxygen release rate of 0.0079 min⁻¹. The nCaO2-FGD achieved OTC removal of 83.92% within 48 h. Radical trapping experiments revealed that hydroxyl radical, superoxide ion, and singlet oxygen play important roles in OTC degradation. The mineralization of the OTC investigated by total organic carbon (TOC) was 71 ± 4%. The nCaO2-FGD dosage, initial OTC concentration, carbonate ion, and humic acid (HA) significantly affected OTC removal, while the initial pH and chloride ion did not at the 95% confidence level. Using response surface methodology, we found that the optimum conditions for treating 10 mg/L of OTC were 53.25 mg/L HA, 558.72 mg/L CO32− and 2,320.75 mg/L CaO2-FGD. The nCaO2-FGD encapsulated in alginate aided in maintaining the pH of water (pH 6.5–7). The nCaO2-FGD was then used to treat real aquaculture water. After 48 h, 10 mg/L of OTC was degraded by 75.83±2.1%. The zooplankton communities in the aquaculture water did not significantly differ before and after treatment. Therefore, our results indicate that nCaO2-FGD is safe for implementation
We investigated, herein, the effects of dietary inclusion of sugarcane bagasse powder (SB) on Nile tilapia development, mucosal and serum immunities, relative immune and antioxi-dant genes. Fish (15.12 ± 0.04 g) were provided a basal diet (SB0) or basal diet incorporated with SB at 10 (SB10), 20 (SB20), 40 (SB40), and 80 (SB80) g kg-1 for 8 weeks. Our results demonstrated that the dietary incorporation of sugarcane baggage powder (SB) at 20 and 40 g kg-1 significant-ly ameliorated FW, WG, and SGR as opposed to fish-fed basal, SB10, and SB80 diets. However, no significant changes in FCR and survivability were observed between the SB supplemented di-ets and the control (basal diet). The mucosal immunity exhibited significantly higher SMLA and SMPA activities (P < 0.005) in fish treated with SB diets after 8 weeks. The highest SMLA and SMPA levels were recorded in fish-fed SB80 accompanied by the SB20, SB40, and SB10, respec-tively. For serum immunity, fish-fed SB incorporated diets significantly ameliorated SL and RB levels (P < 0.05) compared with the control. However, SP was not affected by the inclusion of SB in any diet throughout the experiment. The expression of IL1, IL8, LBP, GSTa, GPX, and GSR genes in the fish liver was significantly increased in fish fed the SB20 and SB10 diets relative to the ba-sal diet fed fish (P<0.05); whereas only the IL8, LBP, and GPX genes in the intestines were sub-stantially augmented in via the SB20 and SB80 diets (P<0.05). IL1 and GSR were not influenced by the SB incorporated diets (P>0.05). In summary, sugarcane bagasse powder (SB) may be ap-plied as a feed additive to improve growth performance, immune response, and immune and an-tioxidant-related gene expression.
In aquaculture, commercial fish such as red hybrid tilapia are usually raised at high density to boost the production within a short period of time. This overcrowded environment, however, may cause stress to the cultured fish and increase susceptibility to infectious diseases. Antibiotics and chemotherapeutics are used by fish farmers to overcome these challenges, but this may increase the production cost. Studies have reported on the potential of mushroom polysaccharides that can act as immunostimulants to enhance the immune response and disease resistance in fish. In the current study, hot water extract (HWE) from mushroom stalk waste (MSW) was used to formulate fish feed and hence administered to red hybrid tilapia to observe the activation of immune system. Upon 30 days of feeding, the fish were challenged with pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharides (LPS) and polyinosinic:polycytidylic acid (poly(I:C)) to mimic bacterial and viral infection, respectively. HWE supplementation promoted better feed utilisation in red hybrid tilapia although it did not increase the body weight gain and specific growth rate compared to the control diet. The innate immunological parameters such as phagocytic activity and respiratory burst activity were significantly higher in HWE-supplemented group than that of the control group following PAMPs challenges. HWE-supplemented diet also resulted in higher mRNA transcription of il1b and tnfa in midgut, spleen and head kidney at 1-day post PAMPs injection. tlr3 exhibited the highest upregulation in the HWE fed fish injected with poly(I:C). At 3-days post PAMPs injection, both ighm and tcrb expression were upregulated significantly in the spleen and head kidney. Results showed that HWE supplementation enhances the immune responses of red hybrid tilapia and induced a higher serum bactericidal activity against S. agalactiae.
This study assessed health and economic impacts of antimicrobial resistance (AMR) in Thailand under societal perspective by using the secondary data on hospitalizations and nosocomial infections from 1,023 hospitals. A total of 87,751 hospitalizations developed nosocomial infections due to 5 major bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobactor baumannii, Pseudomonas aeruginosa and methicillin- resistant Staphylococcus aureus) that are resistant to antibiotics in Thailand in 2010. These AMR infections resulted in additional of at least 3.24 million days of hospitalization and 38,481 deaths. Regarding an economic loss, the cost of antibiotics to be used for therapy of AMR infections were accounted for 2,539 to 6,084 million Baht. The indirect costs of morbidity and mortality due to premature deaths related to AMR were at least 40,000 million Baht (in 2010 values). The aforementioned health and economic impacts of AMR are much higher than the burden of many priority health problems in Thailand. Therefore, AMR is a major and urgent health problem in Thailand that needs comprehensive and systematic approaches at national and local levels to resolve the problem.
Origins Since its adoption for aquaculture Nile tilapia (Oreochromis niloticus) has proven popular for its ease of culture, robust-ness, palatability, and tolerance of a range of environmental conditions. The fi shes' reproductive behaviour was originally seen as one of its most valuable characteristics, making it unnecessary for small-scale farmers to repeatedly purchase hatchery produced seed, and contributed to its promotion and distribution for rural development purposes throughout the tropics. The sub-optimal growth and low or variable size (and market value) which mixed-sex populations of tilapia frequently exhibited acted as a constraint to the species commercial development however, leading to efforts in the 1970's to produce all-male fry in order to circumvent the problem. Despite the obvious promise of such a technical breakthrough no suitable technology for reliably producing all-male tilapia at a commercially viable scale and cost emerged until the mid 1980s. Development of hapa-based broodstock management, which allowed for collection of tilapia eggs and yolk-sac larvae of a uniform age, proved the key to ensuring consistently high (~99%) levels of male fi sh following the application for 21 days of feed treated with 17-α methyltestosterone. This breakthrough occurred as a result of doctoral research initiated at the Asian Institute for Technology (AIT) in 1984 as part of an EU funded project on the intensifi cation of septage-fed aquaculture systems. AIT staff immediately recognised the wider implications of the technology and began to increase production of monosex fry for use in experimental trials, and for sale to forward-thinking commercially oriented fi sh farmers in Central Thailand who were also quick to grasp the potential of all-male tilapia. Word of the benefi ts spread rapidly among this group following the publication of articles in local popular media, and the Institute began promotion monosex seed to small-scale farmers in NE Thailand as part of its development focussed extension activities there, as a result of which it expanded hatchery production to a peak of two million per month in early and mid 1990's. AIT also worked closely with the Thai Department of Fisheries (DOF) to institutionalise adoption of the technology from the late 1980's, and established a short course training program for monosex hatchery production as part of its remit for disseminating development focussed research outputs. Short courses attracted more than 100 participants from the public and private sector both locally and internationally but their effi cacy initially proved somewhat limited, prompting key staff to seek to extend impacts to the private sector through mentoring and support for, and partnership with, private hatcheries.
When oxytetracycline (OTC) medicated feed is fed to fish in a recirculating aquaculture system, antibiotic residues could accumulate in fish tissue, water, biofilter sand and sediment to a greater extent than in single pass or serial reuse aquaculture systems. In two trials, oxytetracycline-medicated feed (3 g active ingredient per pound of feed) was fed to adult rainbow trout at 1% b.w. per day for 10 days. OTC residues were assayed in fish muscle (with skin attached), water, sediment (e.g., fish feces, uneaten feed) and biofilter sand. For both trials, oxytetracycline was detected during the 10 days of treatment in all matrices assayed. In trout muscle, OTC concentrations increased to an average of 1.8 μg/g by day 10 of treatment and then declined to
The Antibiotics Smart Use (ASU) programme was introduced in Thailand as a model to promote the rational use of medicines, starting with antibiotics. The programme's first phase consisted of assessing interventions intended to change prescribing practices; the second phase examined the feasibility of programme scale-up. Currently the programme is in its third phase, which centres on sustainability. This paper describes the concept behind ASU, the programme's functional modalities, the development of its conceptual framework and the implementation of its first and second phases. To change antibiotic prescription practices, multifaceted interventions at the individual and organizational levels were implemented; to maintain behaviour change and scale up the programme, interventions at the network and policy levels were used. The National Health Security Office has adopted ASU as a pay-for-performance criterion, a major achievement that has led to the programme's expansion nationwide. Despite limited resources, programme scale-up and sustainability have been facilitated by the promotion of local ownership and mutual recognition, which have generated pride and commitment. ASU is clearly a workable entry point for efforts to rationalize the use of medicines in Thailand. Its long-term sustainability will require continued local commitment and political support, effective auditing and integration of ASU into routine systems with appropriate financial incentives.
Antibiotics are highly effective, bioactive substances. As a result of their consumption, excretion, and persistence, they are disseminated mostly via excrements and enter the soils and other environmental compartments. Resulting residual concentrations in soils range from a few μg upto g kg–1 and correspond to those found for pesticides. Numerous antibiotic molecules comprise of a non-polar core combined with polar functional moieties. Many antibiotics are amphiphilic or amphoteric and ionize. However, physicochemical properties vary widely among compounds from the various structural classes. Existing analytical methods for environmental samples often combine an extraction with acidic buffered solvents and the use of LC-MS for determination. In soils, adsorption of antibiotics to the organic and mineral exchange sites is mostly due to charge transfer and ion interactions and not to hydrophobic partitioning. Sorption is strongly influenced by the pH of the medium and governs the mobility and transport of the antibiotics. In particular for the strongly adsorbed antibiotics, fast leaching through soils by macropore or preferential transport facilitated by dissolved soil colloids seems to be the major transport process. Antibiotics of numerous classes are photodegraded. However, on soil surfaces this process if of minor influence. Compared to this, biotransformation yields a more effective degradation and inactivation of antibiotics. However, some metabolites still comprise of an antibiotic potency. Degradation of antibiotics is hampered by fixation to the soil matrix; persisting antibiotics were already determined in soils. Effects on soil organisms are very diverse, although all antibiotics are highly bioactive. The absence of effects might in parts be due to a lack of suitable test methods. However, dose and persistence time related effects especially on soil microorganisms are often observed that might cause shifts of the microbial community. Significant effects on soil fauna were only determined for anthelmintics. Due to the antibiotic effect, resistance in soil microorganisms can be provoked by antibiotics. Additionally, the administration of antibiotics mostly causes the formation of resistant microorganisms within the treated body. Hence, resistant microorganisms reach directly the soils with contaminated excrements. When pathogens are resistant or acquire resistance from commensal microorganisms via gene transfer, humans and animals are endangered to suffer from infections that cannot be treated with pharmacotherapy. The uptake into plants even of mobile antibiotics is small. However, effects on plant growth were determined for some species and antibiotics.
Pharmazeutische Antibiotika in Böden – ein Überblick
Antibiotika sind hochgradig wirksame, bioaktive Substanzen. Infolge ihrer Anwendung, Ausscheidung und Persistenz werden sie meist über die Exkremente in Böden und andere Umweltkompartimente eingetragen. Die resultierenden Rückstandskonzentrationen in Böden im Bereich von wenigen μg bis zu g kg–1 entsprechen in etwa denen von Pflanzenschutzmitteln. Die Molekülstruktur von Antibiotika besteht häufig aus einem unpolaren Kern und polaren Randgruppen. Viele Antibiotika sind amphiphil oder amphoter und bilden Ionen, jedoch weisen die zahlreichen Antibiotika unterschiedlicher Strukturklassen stark divergierende physikochemische Eigenschaften auf. In den vorliegenden Nachweis"methoden für Umweltproben werden häufig sauer gepufferte Lösungsmittel zur Extraktion und eine Bestimmung mittels LC-MS kombiniert. Die Adsorption der Antibiotika an den organischen als auch an den mineralischen Bodenaustauschern erfolgt zumeist durch Ladungs- und Ionenwechselwirkungen und weniger durch hydrophobe Bindungen. Das Verteilungsverhalten hängt dabei entscheidend vom pH-Wert des Mediums ab und beeinflusst die Mobilität und Verlagerung der Antibiotika. Bei vielen, insbesondere stark adsorbierten Antibiotika sind v. a. schnelle Fließvorgänge wie durch präferenziellen und Makroporenfluss sowie der Cotransport mit gelösten Bodenkolloiden von besonderer Bedeutung. Antibiotika vieler Strukturklassen können durch Licht abgebaut werden. Dieser Abbaupfad spielt auf Bodenoberflächen jedoch nur eine untergeordnete Rolle. Hingegen kommt es insbesondere durch biologische Transformationsprozesse zu einer intensiven Degradation und Inaktivierung der Antibiotika. Verschiedene Metaboliten weisen jedoch ebenfalls ein antibiotisches Potential auf. Der Abbau der Antibiotika wird durch die Festlegung in Böden gehemmt; dementsprechend wurde eine Persistenz verschiedener Antibiotika nachgewiesen. Trotz der starken bioaktiven Wirkung aller Antibiotika sind die festgestellten Effekte auf Bodenorganismen sehr unterschiedlich. Dies liegt nicht zuletzt an einem Mangel an geeigneten Testmethoden. In der Regel sind jedoch von Dosis und Wirkungsdauer abhängige Effekte insbesondere auf Mikroorganismen festzustellen, die zu Veränderungen der Mikroorganismenpopulation führen können. Lediglich durch Anthelmintika wurden deutliche Wirkungen auf Vertreter der Bodenfauna hervorgerufen. Infolge der antibiotischen Wirkung der Pharmazeutika kann eine Resistenzbildung bei Bodenorganismen ausgelöst werden. Zudem hat die Medikation von Antibiotika die Bildung resistenter Mikroorganismen bereits im behandelten Organismus zur Folge. Durch deren anschließende Ausscheidung gelangen resistente Keime auch direkt in die Böden. Handelt es sich um resistente Pathogene oder kommt es zur Übertragung der Resistenzgene zwischen kommensalen und pathogenen Mikroorganismen, so besteht das erhebliche Risiko einer nicht therapierbaren Infektion von Mensch und Tier. Die Aufnahme selbst mobiler Antibiotika in die Pflanzen ist sehr gering. Dennoch wurden bei einigen Pflanzenarten Wirkungen von Antibiotika auf das Wachstum nachgewiesen.
Southeast Asia has become the center of rapid industrial development and economic growth. However, this growth has far outpaced investment in public infrastructure, leading to the unregulated release of many pollutants, including wastewater-related contaminants such as antibiotics. Antibiotics are of major concern because they can easily be released into the environment from numerous sources, and can subsequently induce development of antibiotic-resistant bacteria. Recent studies have shown that for some categories of drugs this source-to-environment antibiotic resistance relationship is more complex. This review summarizes current understanding regarding the presence of quinolones, sulfonamides, and tetracyclines in aquatic environments of Indochina and the prevalence of bacteria resistant to them. Several noteworthy findings are discussed: (1) quinolone contamination and the occurrence of quinolone resistance are not correlated; (2) occurrence of the sul sulfonamide resistance gene varies geographically; and (3) microbial diversity might be related to the rate of oxytetracycline resistance.
Fluoroquinolone antibiotics (FQs) have been used worldwide for chemotherapy, animal husbandry, and aquaculture, and the occurrence of FQ-resistant (FQs(r)) bacteria in natural environments has been reported. Plasmid-mediated transferable quinolone resistance (PMQR) genes are suspected to originate from the chromosomes of water-dwelling bacteria. However, the occurrence of and the potential reservoir of FQs(r) bacteria and PMQR genes in aquatic environments have not been elucidated. In this study, we detected FQs(r) bacteria and PMQR genes in aquatic environments in Thailand and Vietnam, and measured FQ contamination. Levels of contamination were greater Thailand (avg. 5130, max 46100 ng L(-1)) than in Vietnam (avg. 235, max 1130 ng L(-1)); however, the occurrence of FQs(r) bacteria was higher in Vietnam (~15%) than in Thailand (~7.0%), suggesting that contamination by FQs is not directly linked to the development of FQs(r) bacteria. Diverse taxonomic groups of FQs(r)-bacteria were identified, and one of the PMQR genes, qnrB, was detected from bacteria of environmental origin, not enteric bacteria. This suggests that the environmental bacteria are a potential reservoir of antibiotic resistance determinants even at un-contaminated sites.
The Tha Chin River Basin located in the great central basin of Thailand is used for water supply, aquaculture, transportation, and recreation as well as a sink for wastewater discharges. Because of gradual deterioration of water quality and fishery resources, this study aimed to explain recent status of the river self-remediation efficiency that was influenced by nutrient inputs and outputs from the river system. Field surveys were carried out during May 2007 (early rainy season) and October 2007 (late rainy season) within the Tha Chin River located in 4 provinces; Chainat, Suphan Buri, Nakhon Pathom, and Samut Sakhon. The nutrient budgets in each province section were analyzed. Results indicated that the river was in eutrophic condition all year round. High nitrogen and phosphorus loads from surrounding agricultural land use, agro-industry, and community continuously flew into the river system. Those nutrient concentrations were higher in the early rainy season than the late rainy season. The lowest river zone (in Samut Sakhon province) indicated highest dissolved inorganic nitrogen (DIN) and orthophosphate phosphorus (P) discharges of 145.54 and 36.14 tons/day, respectively. The highest remediation efficiency of the river (ca 60% of the total input) was found in the uppermost area of Suphan Buri province. The lowest remediation efficiency (ca 12%) was found in Samut Sakhon province. From the overall view, long term monitoring of river and estuarine DIN and P should be conducted. To make better condition of aquatic environment and fishery resource in each province-based section, the controls of DIN and P remediation efficiencies (e.g. by effective management of flow speed) at 20 and 50%, respectively, were recommended.
The ubiquity of fluoroquinolone antibiotics (FQs) in surface waters urges insights into their fate in the aqueous euphotic zone. In this study, eight FQs (ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin, enrofloxacin, gatifloxacin, and balofloxacin) were exposed to simulated sunlight, and their photodegradation was observed to follow apparent first-order kinetics. Based on the determined photolytic quantum yields, solar photodegradation half-lives for the FQs in pure water and at 45 degrees N latitude were calculated to range from 1.25 min for enrofloxacin to 58.0 min for balofloxacin, suggesting that FQs would intrinsically photodegrade fast in sunlit surface waters. However, we found freshwater and seawater constituents inhibited their photodegradation. The inhibition was further explored by a central composite design using sarafloxacin and gatifloxacin as representatives. Humic acids (HA), Fe(III), NO(3)(-), and HA-Cl(-) interaction inhibited the photodegradation, as they mainly acted as radiation filters and/or scavengers for reactive oxygen species. The photodegradation product identification and ROS scavenging experiments indicated that the FQs underwent both direct photolysis and self-sensitized photo-oxidation via *OH and (1)O(2). Piperazinyl N(4)-dealkylation was primary for N(4)-alkylated FQs, whereas decarboxylation and defluorination were comparatively important for the other FQs. These results are of importance toward the goal of assessing the persistence of FQs in surface waters.
Global environmental change poses emerging environmental health challenges throughout the world. One of such threats could be found in chemical safety in aquatic ecosystem. In the present study, we evaluated the effect of several environmental factors, such as water pH, temperature and ultraviolet light on the toxicity of pharmaceutical compounds in water, using freshwater invertebrate Daphnia magna. Seven pharmaceuticals including ibuprofen, acetaminophen, lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline and sulfathiazole were chosen as test compounds based on their frequent detection in water. The experimental conditions of environmental parameters were selected within the ranges that could be encountered in temperate environment, i.e., water temperature (15, 21, and 25 degrees C), pH (7.4, 8.3, and 9.2), and UV-B light intensity (continuous irradiation of 15.0 microW/cm(2)). For acetaminophen, enrofloxacin and sulfathiazole, decrease in water pH generally led to increase of acute lethal toxicity, which could be explained by the unionized fraction of pharmaceuticals. Increase of water temperature enhanced the acute toxicity of the acetaminophen, enrofloxacin and chlortetracycline, potentially due to alteration in toxicokinetics of chemicals as well as impact on physiological mechanisms of the test organism. The presence of UV-B light significantly increased the toxicity of sulfathiazole, which could be explained by photo-modification of this chemical that lead to oxidative stress. Under the UV light, however, acute toxicity of enrofloxacin decreased, which might be due to photo-degradation. Since changing environmental conditions could affect exposure and concentration-response profile of environmental contaminants, such conditions should be identified and evaluated in order to better manage ecosystem health under changing global environment.
This report was written as a manual for the software program, ETX 2.0. The calculation techniques offered here are currently in use in the RIVM project, 'Setting (inter)national environmental quality criteria' (INS), and the EU risk assessment for existing substances. Environmental risk limits for chemical substances are derived here. Both the INS and EU frameworks allow for statistical extrapolation in the presence of sufficient toxicity data, which serves as a basis for an environmental risk limit (INS) or a predicted no-effect concentration (EU existing substances) of a chemical substance. A statistical technique for achieving this result, recently described in the scientific literature, is made accessible to those working on risk assessment and/or standard-setting through the ETX 2.0 program. A CD-ROM is delivered along with the report. Dit rapport is geschreven als handleiding bij het software programma ETX 2.0. De rekentechnieken die met dit programma worden aangeboden worden onder andere gebruikt binnen het RIVM project '(Inter)nationale normstelling stoffen' (INS) maar ook bij de Europese risico-beoordeling van bestaande stoffen. In deze projecten worden milieurisicogrenzen afgeleid voor chemische stoffen. Zowel het INS- als het EU-raamwerk staat het gebruik van statistische extrapolatie toe wanneer voldoende toxiciteitsgegevens beschikbaar zijn. De resultaten van deze extrapolatie dienen als basis voor een milieurisicogrens (INS) of een geen-effect niveau (EU bestaande stoffen) van een chemische stof. In de wetenschappelijke literatuur is recent een methode beschreven om deze statistische berekening uit te voeren. Het programma ETX 2.0 maakt deze methode toegankelijk voor hen die werkzaam zijn in de vakgebieden van de risicobeoordeling en/of normstelling. Het programma wordt samen met dit rapport verspreid op CD-ROM.
Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. The first tetracycline-resistant bacterium, Shigella dysenteriae, was isolated in 1953. Tetracycline resistance now occurs in an increasing number of pathogenic, opportunistic, and commensal bacteria. The presence of tetracycline-resistant pathogens limits the use of these agents in treatment of disease. Tetracycline resistance is often due to the acquisition of new genes, which code for energy-dependent efflux of tetracyclines or for a protein that protects bacterial ribosomes from the action of tetracyclines. Many of these genes are associated with mobile plasmids or transposons and can be distinguished from each other using molecular methods including DNA-DNA hybridization with oligonucleotide probes and DNA sequencing. A limited number of bacteria acquire resistance by mutations, which alter the permeability of the outer membrane porins and/or lipopolysaccharides in the outer membrane, change the regulation of innate efflux systems, or alter the 16S rRNA. New tetracycline derivatives are being examined, although their role in treatment is not clear. Changing the use of tetracyclines in human and animal health as well as in food production is needed if we are to continue to use this class of broad-spectrum antimicrobials through the present century.
Asia contributes more than 90% to the world's aquaculture production. Like other farming systems, aquaculture is plagued with disease problems resulting from its intensification and commercialization. This paper describes the various factors, providing specific examples, which have contributed to the current disease problems faced by what is now the fastest growing food-producing sector globally. These include increased globalization of trade and markets; the intensification of fish-farming practices through the movement of broodstock, postlarvae, fry and fingerlings; the introduction of new species for aquaculture development; the expansion of the ornamental fish trade; the enhancement of marine and coastal areas through the stocking of aquatic animals raised in hatcheries; the unanticipated interactions between cultured and wild populations of aquatic animals; poor or lack of effective biosecurity measures; slow awareness on emerging diseases; the misunderstanding and misuse of specific pathogen free (SPF) stocks; climate change; other human-mediated movements of aquaculture commodities. Data on the socio-economic impacts of aquatic animal diseases are also presented, including estimates of losses in production, direct and indirect income and employment, market access or share of investment, and consumer confidence; food availability; industry failures. Examples of costs of investment in aquatic animal health-related activities, including national strategies, research, surveillance, control and other health management programmes are also provided. Finally, the strategies currently being implemented in the Asian region to deal with transboundary diseases affecting the aquaculture sector are highlighted. These include compliance with international codes, and development and implementation of regional guidelines and national aquatic animal health strategies; new diagnostic and therapeutic techniques and new information technology; new biosecurity measures including risk analysis, epidemiology, surveillance, reporting and planning for emergency response to epizootics; targeted research; institutional strengthening and manpower development (education, training and extension research and diagnostic services).
In this study, eleven commonly used antibiotics including sulfonamides, tetracyclines, aminoglycosides, fluoroquinolones, and beta-lactams were evaluated for their acute and chronic aquatic toxicities using standard test organisms e.g., Vibrio fischeri, Daphnia magna, Moina macrocopa, and Oryzias latipes. Among the antibiotics tested for acute toxicity, neomycin was most toxic followed by trimethoprim, sulfamethoxazole and enrofloxacin. Sulfamethazine, oxytetracycline, chlortetracycline, sulfadimethoxine and sulfathiazole were of intermediate toxicity, while ampicillin and amoxicillin were least toxic to the test organisms. There were no trends in sensitivity among test organisms or among different classes of the antibiotics. Only the beta-lactam class was the least toxic. In chronic toxicity test, neomycin affected reproduction and adult survival of D. magna and M. macrocopa with low mg/l levels exposure. Predicted no effect concentrations (PNECs) were derived from the acute and chronic toxicity information gleaned from this study and from literature. When the PNECs were compared with measured environmental concentrations (MECs) reported elsewhere for the test compounds, hazard quotients for sulfamethoxazole, sulfathiazole, chlortetracycline, oxytetracycline, and amoxicillin exceeded unity, which suggests potential ecological implication. Therefore, further studies including monitoring and detailed toxicological studies are required to assess potential ecological risk of these frequently used veterinary antibiotics.
In spite of the growing importance of Species Sensitivity Distribution models (SSDs) in ecological risk assessments, the conceptual basis, strengths, and weaknesses of using them have not been comprehensively reviewed. This book fills that need. Written by a panel of international experts, Species Sensitivity Distributions in Ecotoxicology reviews the current SSD methods from all angles, compiling for the first time the variety of contemporary applications of SSD-based methods. Beginning with an introduction to SSDs, the chapter authors review the issues surrounding SSDs, synthesizing the positions of advocates and critics with their own analysis of each issue. Finally, they discuss the prospects for future development, paving the way for improved future uses. In sum, this book defines the field of SSD modeling and application. It reveals a lively field, with SSD-applications extending beyond legally adopted quality criteria to other applications such as Life-Cycle Analysis. For anyone developing or revising environmental criteria or standards, this book explores the pros and cons of using the SSD approach. For anyone who needs to apply and interpret SSD-based criteria or standards, the book explains the basis for the numbers, thereby making it possible to correctly apply and defend them. For anyone performing ecological risk assessments, the book covers when and how to use SSDs including alternative assumptions, data treatments, computational methods, and available resources. Species Sensitivity Distributions in Ecotoxicology provides you with a clear picture of these standard models for estimating ecological risks from laboratory toxicity data.
The binding of six tetracyclines to borosilicate glass or polypropylene test tubes was studied in vitro, and included chlorotetracycline, demeclocycline, doxycycline, minocycline, oxytetracycline, and tetracycline. All tetracyclines bound to borosilicate glass test tubes, and minocycline bound the most. Both time for binding to occur, and exposure to increasing amounts of surface area were involved in the production of increased binding, but the binding was mostly due to surface area. Doxycycline and minocycline significantly bound to polypropylene test tubes, whereas all of the other tetracyclines did not. This study suggests that all containers should be tested for possible binding of tetracyclines before use, and polypropylene labware is less likely to bind tetracyclines, compared to borosilicate glass.
Over the past few decades, Asian aquaculture production has intensified rapidly
through the adoption of technological advances, and the use of a wide array of
chemical and biological products to control sediment and water quality and to
treat and prevent disease outbreaks. The use of chemicals in aquaculture farms
has raised environmental concerns owing to their potential impacts on downstream
aquatic ecosystems. Currently little is known about the environmental
fate and effects of the chemicals used in Asian aquaculture. Consequently, we
reviewed recent information on the use of chemical and biological products in
the most important Asian aquaculture producing countries and briefly summarize
their main potential environmental impacts. We provide an overview of
the main factors controlling the use of these chemicals and describe the international
risk assessment guidelines available for aquaculture chemicals. Finally,
data gaps and research needs for their implementation in Asian countries are
discussed. Our review aims to form a basis for developing environmental risk
assessment studies of the chemicals used in Asian aquaculture.
A 2-year study of extensive and intensive fish hatcheries was conducted to assess the general temporal occurrence of antibiotics in aquaculture. Antibiotics were detected in 15% of the water samples collected during the 2001-2002 collection period and in 31% of the samples during the 2003 collection period. Antibiotics were detected more frequently in samples from the intensive hatcheries (17 and 39%) than in samples from the extensive hatcheries (14 and 4%) during the 2001-2002 and 2003 collection periods, respectively. The maximum ormetoprim, oxytetracycline, and sulphadimethoxine concentrations were higher in samples from the intensive hatcheries (12, 10, and 36 µg L-1), respectively, than in samples from the extensive hatcheries (<0.05, 0.31, and 1.2 µg L-1), respectively. Sulphadimethoxine persisted for a longer period of time (up to 48 days) than ormetoprim (up to 28 days) and oxytetracycline (less than 20 days).
Large quantities of fluoroquinolone carboxylic acid (FQCA) derivatives are applied as antibacterial agents in large-scale animal husbandry. Important quantities are transported to agricultural areas by means of liquid manure. The binding of FQCA derivatives to clay minerals and their sorption by five soils from different geographic areas were investigated. Sorption was studied in batch experiments using radioactive labeled enrofloxacin (Baytril), decarboxylated enrofloxacin, ciprofloxacin (Cyprobay), levofloxacin (Oxaldin), and a fluorochloroquinolone carboxylic acid derivative. More than 90% (KD = 260−5612) of the applied enrofloxacin adsorbed on the different soils. The other chemicals showed a similar adsorption (KD = 285−496) on a German soil except the decarboxylated enrofloxacin (KD = 7.7). At clay minerals enrofloxacin was adsorbed >98%. X-ray diffraction analysis showed that the adsorption at the clay mineral montmorillonite occurred between the layers, resulting in an expansion of the spacing. Microcalorimetric and infrared measurements confirmed an electrostatic interaction between the adsorbed chemical and the adsorbent. Keywords: Adsorption; clay mineral; enrofloxacin; fluoroquinolone carboxylic acid derivatives; Coulombic interactions; soil clays
Leaching of oxytetracycline, oxolinic acid, amoxycillin and the potentiated sulphonamide trimethoprim/ sulphamethoxazote (TMP/SMX) from surface-coated fish-feed pellets, surrounded with either cod liver oil or with calcium-alginate, was investigated. Despite the low water temperature (12°C), losses of amoxycillin, oxytetracycline and TMP/SMX from the oil-coated feed were high with 41.6-67.3% of the drugs lost after 15 min immersion. By contrast, less than 20% of oxolinic acid was lost within the same interval. When calcium-alginate was used, leaching rates were found to be considerably lower. Losses of TMP/SMX. amoxycillin and oxytetracycline ranged from 6.3 to 24.1% within 15 min. Leaching of oxolinic acid was completely prevented by the alginate.
Species in the environment vary according to their sensitivity to a toxicant. Because these differences in sensitivity are unique to the toxicant at consideration and laboratory data sets to assess this variability are very small due to cost, it is important to provide uncertainty estimates of (1) environmental quality objectives (hazardous concentrations) derived from these laboratory data and (2) fraction of species affected at given, or predicted, laboratory or environmental concentrations. This article focuses on the normal (Gaussian) distribution of species sensitivity. It examines and compares results of Problems (1) and (2) from two opposing statistical philosophies, Bayesian and Classical, leading to vastly different numerical approaches. For the normal model, both approaches lead to identical answers, numerically. Extrapolation factors for the lower, median, and upper estimates of the hazardous concentration at six levels of protection are derived. Furthermore, upper, median, and lower estimates of the fraction affected at given, standardized, logarithmic concentrations have been tabulated. This table can be used directly for risk assessment without reference to protection levels or hazardous concentrations. The confidence limits for hazardous concentration and fraction affected depend heavily on the number of species tested and are independent of the toxic substance involved (provided the model is right), due to correction for the mean and standard deviation of the toxicity data. The equivalence of confidence limits for hazardous concentration and fraction affected is captured in the law of extrapolation: the upper (median, lower) confidence limit for the fraction affected at the lower (median, upper) confidence limit of the hazardous concentration is equal to the fraction affected (e.g., 5%) used to define the hazardous concentration. The upper confidence limit for the fracti