Assessing the Ecotoxicity of Eight Widely Used Antibiotics on River Microbial Communities
International Journal of Molecular Sciences (IJMS)
Abstract and Figures
Global prevalence of antibiotic residues (ABX) in rivers requires ecotoxicological impact assessment. River microbial communities serve as effective bioindicators for this purpose. We quantified the effects of eight commonly used ABXs on a freshwater river microbial community using Biolog EcoPlates™, enabling the assessment of growth and physiological profile changes. Microbial community characterization involved 16S rRNA gene sequencing. The river community structure was representative of aquatic ecosystems, with the prevalence of Cyanobacteria, Proteobacteria, Actinobacteria, and Bacteroidetes. Our findings reveal that all ABXs at 100 µg/mL reduced microbial community growth and metabolic capacity, particularly for polymers, carbohydrates, carboxylic, and ketonic acids. Chloramphenicol, erythromycin, and gentamicin exhibited the highest toxicity, with chloramphenicol notably impairing the metabolism of all studied metabolite groups. At lower concentrations (1 µg/mL), some ABXs slightly enhanced growth and the capacity to metabolize substrates, such as carbohydrates, carboxylic, and ketonic acids, and amines, except for amoxicillin, which decreased the metabolic capacity across all metabolites. We explored potential correlations between physicochemical parameters and drug mechanisms to understand drug bioavailability. Acute toxicity effects at the river-detected low concentrations (ng/L) are unlikely. However, they may disrupt microbial communities in aquatic ecosystems. The utilization of a wide array of genetically characterized microbial communities, as opposed to a single species, enables a better understanding of the impact of ABXs on complex river ecosystems.
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... Across the levels of species, genus, family, order, class, phylum, and kingdom, the proportion of total reads ranged from 94.13% to 99.35%, while for species, it constituted 79.00%, Figure S1 and Table S1. This microbial profile of the water sample is representative of a fluvial environment in the Mediterranean area and similar to that reported by other studies [92,93]. ...
... When comparing the effects of EUG and commercial ABXs (the ones used in the antimicrobial experiments) [93] on water microbiota, our EUG data revealed a weaker impact on AWCD. EUG and commercial ABXs caused a significant reduction in AWCD only at 1000 mg/L, but GTM, CHL, and TC also induced significant decreases at 100 mg/L [93]. ...
... When comparing the effects of EUG and commercial ABXs (the ones used in the antimicrobial experiments) [93] on water microbiota, our EUG data revealed a weaker impact on AWCD. EUG and commercial ABXs caused a significant reduction in AWCD only at 1000 mg/L, but GTM, CHL, and TC also induced significant decreases at 100 mg/L [93]. Regarding CLPP, EUG showed substantial metabolic differences compared to the control at 1000 mg/L for all metabolic groups except amino acids, which exhibited differences at 100 mg/L. ...
Combining commercial antibiotics with adjuvants to lower their minimum inhibitory concentration (MIC) is vital in combating antimicrobial resistance. Evaluating the ecotoxicity of such compounds is crucial due to environmental and health risks. Here, eugenol was assessed as an adjuvant for 7 commercial antibiotics against 14 pathogenic bacteria in vitro, also examining its acute ecotoxicity on various soil and water organisms (microbiota, Vibrio fischeri, Daphnia magna, Eisenia foetida, and Allium cepa). Using microdilution methods, checkerboard assays, and kinetic studies, the MICs for eugenol were determined together with the nature of its combinations with antibiotics against bacteria, some unexposed to eugenol previously. The lethal dose for the non-target organisms was also determined, as well as the Average Well Color Development and the Community-Level Physiological Profiling for soil and water microbiota. Our findings indicate that eugenol significantly reduces MICs by 75 to 98%, which means that it could be a potent adjuvant. Ecotoxicological assessments showed eugenol to be less harmful to water and soil microbiota compared to studied antibiotics. While Vibrio fischeri and Daphnia magna were susceptible, Allium cepa and Eisenia foetida were minimally affected. Given that only 0.1% of eugenol is excreted by humans without metabolism, its environmental risk when used with antibiotics appears minimal.
... The concentration of antibiotics in the environment is an important factor in the degradation process. Pino-Otín et al. (2023) observed that the increase in concentrations (>100 µg/mL in river) of antibiotics leads to the inhibition of microbial growth. Similarly, low concentration i.e. <1 µg carbon/L of water cannot be detected by microbial community resulting in the reduction of the degradation process (Duygan et al., 2021). ...
Antibiotics are essential for resisting bacterial infections and have been extensively used as medicine for humans, and animals. Excessive usage of antibiotics has led to an increased population of antibiotic-resistant microbes and antibiotic-resistant genes (ARGs) are becoming a threat to human and animal health. Microbial degradation of antibiotics for the removal of these compounds in both natural and synthetic environments depend on their optimal growth condition such as pH, temperature, trace elements, carbon and nitrogen sources. Biological approaches for the removal of pollutants have several advantages over physical and chemical processes, such as cost and eco-friendly benefits. However, the mechanisms and processes of antibiotic degradation in the environment are not well known. Microbes possess antibiotic degrading enzymes such as beta lactamase, esterase, nitroreductases, hydroquinone dioxygenase, ammonia monooxygenase, laccase, peroxidase and peroxygenase showing their evolutionary modification in response to the selective pressures of antibiotic exposure. Algae-based technologies provide advantages like CO2 fixation, low ecological impact, harnessing solar energy and ability to produce biofuel and other valuable by-products while simultaneously degrading antibiotics. Rhizospheric bacteria play a crucial role in antibiotic degradation in response to environmental stress, which leads to improved adaptation and enhanced growth of plants. This review aims to summarize the various bioremediation strategies that can be employed for the degradation of antibiotics and the mechanisms involved in the degradation by bacteria, algae and fungi in the biodegradation of antibiotics. Understanding these pathways of microbe mediated degradation will help us to discover research connected to the metabolomics of these pathways and recent advancements in bioremediation.
Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) represent two burgeoning categories of advanced porous materials that have garnered substantial interests within the scientific community in recent years. Notably,...
In this paper we produced a bio-based polyether-polyurethane foam PU1 through the prepolymer method. The prepolymer was obtained by the reaction of PEG 400 with L-Lysine ethyl ester diisocyanate (L-LDI). The freshly prepared prepolymer was extended with 2,5-bis(hydroxymethyl)furan (BHMF) to produce the final polyurethane. The renewable chemical BHMF was produced through the chemical reduction of HMF by sodium borohydride. HMF was produced by a previously reported procedure from fructose using choline chloride and ytterbium triflate. To evaluate the degradation rate of the foam PU1, we tested the chemical stability by soaking it in a 10% sodium hydroxide solution. The weight loss was only 12% after 30 days. After that, we proved that enzymatic hydrolysis after 30 days using cholesterol esterase was more favoured than hydrolysis with NaOH, with a weight loss of 24%, probably due to the hydrophobic character of the PU1 and a better adhesion of the enzyme on the surface with respect to water. BHMF was proved to be of crucial importance for the enzymatic degradation assay at 37 °C in phosphate buffer solution, because it represents the breaking point inside the polyurethane chain. Soil burial degradation test was monitored for three months to evaluate whether the joint activity of sunlight, climate changes and microorganisms, including bacteria and fungi, could further increase the biodegradation. The unexpected weight loss after soil burial degradation test was 45% after three months. This paper highlights the potential of using sustainable resources to produce new biodegradable materials.
Environmental aquatic pollution with antibiotics is a global challenge that affects even pristine mountain environments. Monitoring the concentration of antibiotics in water is critical to water resource management. In this review, we present the sources and degradation routes of antibiotics polluting surface waters, with particular focus on mountain environments and pristine areas. This pollution is strongly related to anthropopressure resulting from intensive tourism. An important aspect of the threat to the environment is water containing antibiotics at sub-inhibitory concentrations, which affects bacterial populations. Antibiotics are ecological factors driving microbial evolution by changing the bacterial community composition, inhibiting or promoting their ecological functions, and enriching and maintaining drug resistance. We paid attention to the stability of antibiotics and their half-lives in water related to biotic and abiotic degradation, which results from the structures of molecules and environmental conditions. Wastewater treatment combined with advanced treatment techniques significantly increase the efficiency of antibiotic removal from wastewater. Modern methods of wastewater treatment are crucial in reducing the supply of antibiotics to aquatic environments and enhancing the possibility of economic and safe reuse of wastewater for technical purposes. We provide a perspective on current research investigating antibiotic emergence in mountain areas and identify knowledge gaps in this field.
The aim of the present work is to evaluate the rate and mechanisms of the aerobic biodegradation of biopolymer blends under controlled composting conditions using the CO2 evolution respirometric method. The biopolymer blends of poly (butylene adipate terephthalate) (PBAT) blended with poly (lactic acid) (PLA), and PBAT blended with poly (butylene succinate) (PBS) by melt extrusion, were tested to evaluate the amount of carbon mineralized under home and industrial composting conditions. The changes in the structural, chemical, thermal and morphological characteristics of the biopolymer blends before and after biodegradation were investigated by FT-IR, DSC, TGA, XRD and SEM. Both blends showed higher degradation rates under industrial composting conditions, when compared to home composting conditions. This was confirmed by FT-IR analysis showing an increase in the intensity of hydroxyl and carbonyl absorption bands. SEM revealed that there was microbial colony formation and disintegration on the surfaces of the biopolymer blends. The obtained results suggest that industrial composting conditions are the most suitable for an enhanced biodegradation of the biopolymer blends viz PBAT–PBS and PBAT–PLA.
At present, research on the influence of human activities (especially urbanization) on the microbial diversity, structural composition, and spatial distribution of rivers is limited. In this paper, to explore the prokaryotic community structure and the relationship between the community and environmental factors in the Jialing River Basin of Chongqing, so as to provide a basis for monitoring microorganisms in the watershed. The V3–V4 region of the 16 S rRNA gene was analyzed by high-throughput sequencing and the microbial community of the waters of the Jialing River was analyzed for the diversity and composition of the prokaryotic community as well as the species difference of four samples and correlations with environmental factors. The main results of this study were as follows: (1) The diversity index showed that there were significant differences in the biodiversity among the four regions. At the genus level, Limnohabitans, unclassified_f_Comamonadaceae, and Hgcl_clade were the main dominant flora with a high abundance and evenness. (2) A Kruskal–Wallis H test was used to analyze the differences of species composition among the communities and the following conclusions were drawn: each group contained a relatively high abundance of Limnohabitans; the Shapingba District had a higher abundance of Limnohabitans, the Hechuan District had a wide range of unclassified_f_Comamonadaceae, and the Beibei District had a higher Hgcl_clade. (3) Through the determination of the physical and chemical indicators of the water—namely, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll A, and an analysis by an RDA diagram, the results demonstrated that the distribution of microbial colonies was significantly affected by the environmental factors of the water. Chemical oxygen demand and ammonia nitrogen had a significant influence on the distribution of the colonies. Different biological colonies were also affected by different environmental factors.
The increased usage of antibiotics over the recent years has been of great concern all over the world. It is estimated that about 100,000 tons to 200,000 tons of antibiotics are being consumed worldwide. This increased consumption of antibiotics is worrisome as this has resulted in their detection in wastewater treatment plants’ (WWTPs) effluent due to the inability of WWTP to remove them during treatment processes. The antibiotics may emanate from hospital effluents, surface waters, and sediments around the world. However, the migration of antibiotics to the environment is detrimental to public health since it can lead to antibiotics resistance in both humans and animals which has now been reported to be one of the biggest threats to public health in this twenty-first century. This present review work established from literature the presence, concentrations, and types of antibiotics both in influents and effluents of various waste treatment plants, natural water bodies, and hospital wastewaters from different countries over the past 10 years (2010–2019). A total of 78 published articles containing information on the presence of antibiotics in convectional and hospital wastewater and also in surface water were retrieved from scientific databases such as ScienceDirect, Google Scholar, PubMed, and Web of Science. A total of 39 different types of antibiotics from 10 different classes of antibiotics and others were recorded. Among the articles reviewed, the most frequently detected antibiotics are the classes of sulfonamides (sulfamethoxazole) which were present in almost all the WWTPs at concentrations as high as 10–800 ng/l in influent and 3600–68,700 ng/l in effluent samples. Macrolides (clarithromycin, erythromycin, azithromycin), trimethoprim, quinolones (ofloxacin, ciprofloxacin, norfloxacin), and tetracyclines (tetracycline) were also highly present in all treatment plants. β-Lactam antibiotics were seldom detected which might be due to hydrolysis. Most of the antibiotics present were recorded in Asian countries such as China and Singapore which have occurrence frequency of 6–30% and in European countries such as Greece and Spain with frequencies of about 6–10%. Future researches on the need for development of more reliable and cost-effective technologies for antibiotic removal such as advanced oxidation processes and remediation methods are suggested for more research attention.
Wastewater treatment plants (WWTPs) are considered important sources of antibiotics and metabolites in aquatic environments and pose a serious threat to the safety of aquatic organisms. In this study, we investigated the seasonal occurrence, removal, emission, and environmental risk assessment (ERA) of 32 antibiotics and metabolites at four WWTPs located in Wuhu, China. The main findings of this study are as follows: Ofloxacin concentrations dominated all WWTPs, and large quantities of sulfachinoxalin were only detected in WWTP 2 treating mixed sewage. The average apparent removal of individual parent antibiotics or metabolites ranged from -94.7 to 100 %. There was a noticeable seasonal emission pattern (independent t-test, t = 9.89, p < 0.001), with lower emissions observed during summer. WWTPs discharged 85.2 ± 43.8 g of antibiotics and metabolites each day. Approximately 87 % of emissions were discharged into the mainstream of the Yangtze River, while the remainder were discharged into its tributary, the Zhanghe River. The total emissions of 21 parent antibiotics were approximately 18 % of the prescription data, indicating that a considerable and alarming amount of prototype drugs entered the receiving water body. Based on the risk quotient (RQ) of the ERA, the Zhanghe River has a moderate risk of ofloxacin (RQ = 0.111-0.583), a low or insignificant risk of sulfamethoxazole (RQ = 0.003-0.048), and an insignificant risk of other antibiotics or metabolites. However, the risk of antibiotics or metabolites in the mainstream of Yangtze River is insignificant. This study could help understand the seasonal emission patterns of antibiotics and metabolites, as well as more antibiotics sensitive of environmental risks in tributary than that in mainstream.
The aim of this study was to determine the wastewaters antibiotic residues concentration in two hospitals (CHU Point G and CHU Luxembourg) in Bamako.
Methods:
The samples of wastewater were collected three times consecutively on three days every week at 9 a.m., 3 p.m. and 9 p.m. in 2016. The samples were stored at 4°C and transferred to the veterinary central laboratory (LCV). The antibiotic residues were detected by High Performance Liquid Chromatography and the antibiotic concentrations were determined by a spectrophotometer UV-Visible Hewlett Packard.
Results:
The detected and measured antibiotic residues were amoxicillin ((0.066 ± 0.08 µg/l), erythromycin (0.04 ± 0.0 µg/l), co-trimoxazole (sulfamethoxazole 0.06 ± 0.21 µg/l + trimethoprime 0.08 ± 0.006 µg/l) and metronidazole (0.02 ± 0.0 µg/l in the hospital wastewater and in the sewer systems. Amoxicillin and sulfamethoxazole were detected before and after the Point G wastewater treatment. No antibiotic residue was detected in the "Chikoroni" sewer system which discharged the Point G wastewater. Amoxicillin and sulfamethoxazole were also detected in the wastewater of the hospital "le Luxembourg" which doesn't have a wastewater treatment plant and in the "Djafranako" sewer system which discharged the wastewater of this hospital. Erythromycin and metronidazole were detected only in the Point G wastewater. Chloramphenicol, ciprofloxacin and tetracyclin were not detected in the two hospital wastewater. The antibiotic residues concentrations at the different moments show the same high level in the different sites.
Conclusion:
Hospitals play a role in the antibiotic dissemination into the environment. In Bamako, the wastewater quality is not alarming, but every hospital must get a sewer system.
Antibiotic resistance genes (ARGs) are an emerging issue for drinking water safety. However, the seasonal variation of ARGs in drinking water distribution systems (DWDS) is still unclear. This work revealed the tempo-spatial changes of microbial community, ARGs, mobile genetic elements (MGEs) co-occurring with ARGs, ARG hosts in DWDS bulk water by means of metagenome assembly. The microbial community and antibiotic resistome varied with sampling season and site. Temperature, ammonia, chlorite and total plate count (TPC) drove the variations of microbial community structure. Moreover, environmental parameters (total organic carbon (TOC), chlorite, TPC and hardness) shifted antibiotic resistome. ARGs and MGEs co-occurring with ARGs showed higher relative abundance in summer and autumn, which might be attributed to detached pipe biofilm. In particular, ARG-bacitracin and plasmid were the predominant ARG and MGE, respectively. ARG hosts changed with season and site and were more diverse in summer and autumn. In winter and spring, Limnohabitans and Mycobacterium were the major ARG hosts as well as the dominant genera in microbial community. In addition, in summer and autumn, high relative abundance of Achromobacter and Stenotrophomonas were the hosts harboring many kinds of ARGs and MGEs at site in a residential zone (0.4 km from the water treatment plant). Compared with MGEs, microbial community had a greater contribution to the variation of antibiotic resistome. This work gives new insights into the dynamics of ARGs in full-scale DWDS and the underlying factors.
Antibiotics’ (ATBs) occurrence in soil ecosystems has a relevant effect in the structure and functionality of edaphic microbial communities, mainly because of their amendment with manure and biosolids that alter their key ecological functions.
In this study, the impact of eight widely consumed ATBs on a natural soil microbial community, characterized through 16 S rRNA gene sequencing, was evaluated. Changes induced by the ATBs in the growth of the soil microbiota and in the community-level physiological profiling (CLPP), using Biolog EcoPlates™, were measured as endpoint.
The eight assayed ATBs lead to a significant decrease in the growth of soil microbial communities in a dose-dependent way, ordered by its effect as follows: chloramphenicol > gentamycin > erythromycin > ampicillin > penicillin > amoxicillin > tetracycline > streptomycin. Chloramphenicol, gentamycin, and erythromycin adversely affected the physiological profile of the soil community, especially its ability to metabolize amino acids, carboxylic and ketonic acids and polymers. The analysis of the relationship between the physico-chemical properties of ATBs, as well as their mechanism of action, revealed that, except for the aminoglycosides, each ATB is influenced by a different physico-chemical parameters, even for ATBs of the same family.
Significant effects were detected from 100 μg mL to 1, concentrations that can be found in digested sludge, biosolids and even in fertilized soils after repeated application of manure, so cumulative and long-term effects of these antibiotics on soil environment cannot be ruled out.
Arthrospira platensis is a kind of filament cyanobacteria, which is mainly helical with a few linear. The shape of the filaments, such as the length and the pitch, may change with the changes in the environment. Natural Arthrospira platensis FACHB793 is linear, although it has become helical due to a mutation introduced in the process of cultivation. To study the molecular mechanism responsible for the morphological changes of the filaments, two samples were isolated from a natural mutant of Arthrospira platensis FACHB793, which were helical shaped (named A793_H) and linear shaped (named A793_L). Transcriptome sequencing, GO and KEGG enrichment analysis showed that the expression of genes related to or involved in peptidoglycan biosynthesis, beta lactam resistance, photosynthetic antenna protein expression, bacterial secretion, and ABC transporter activity changed between the two samples. The expression of murE and murG in the peptidoglycan biosynthesis pathway and that of oppD in beta lactam resistance were all down-regulated in the linear filaments, which may be related to the longer cell wall and higher peptidoglycan synthesis in linear filaments than helical filaments. In helical filaments, the up-regulation of tatC gene expression in bacterial secretion may be related to the secretion of peptidoglycan degrading enzymes, which may help to change the shape from linear to helical. Moreover, apcA and cpcA in photosynthetic antenna protein expression and nrt and nirA in nitrogen metabolism were all down regulated in the helical filaments, which may be due to the deformed shape of A. platensis FACHB793, resulting in decreased photosynthetic activity in helical filaments. This research provides a foundation for elucidating the possible morphogenetic mechanism of Arthrospira platensis.