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Exploring the potential of zinc oxide nanoparticles against pathogenic multi-drug resistance Staphylococcus aureus from ready-to-eat meat and its proposed mechanism
... Our MR S A count findings ranged from undetectable lev- els to 9.8 × 10 4 ± 2.47 CFU/g, similar to other studies. Sobhy et al. ( 2024 ) reported counts ranging from 1.14104 to 7.4103 CFU/g, comparable to our findings. Thwala et al. ( 2022 ) found counts overlapping with our lower MR S A counts. ...
... For instance, Salamandane et al. ( 2023 ) and Aksoy ( 2021 ) reported detection rates ranging from 5.3% to 57.9% for virulence genes. Pérez-Boto et al. ( 2023 ) noted that 53% of isolates harboured enterotoxin genes, while Sobhy et al. ( 2024 ) observed a 55.6% prevalence of the se a and sea genes. Wang et al. ( 2023 ) identified nine toxin genes in MR S A isolates, with 60% carrying multiple toxin genes. ...
... Salamandane et al. ( 2022 ) reported substantial mecA and vanA prevalence, indicating significant methicillin and vancomycin resistance. Sobhy et al. ( 2024 ) demonstrated a complex genetic landscape of AMR. Thwala et al. ( 2022 ) identified mecC , suggesting alternative methicillin resistance. ...
Ready-to-eat (RTE) foods are susceptible to contamination with methicillin-resistant Staphylococcus aureus (MRSA), presenting significant health risks to consumers. This study aimed to isolate, identify, and characterize MRSA from RTE foods in Delta, Nigeria, and assess their implications for consumer safety. Four hundred RTE food samples were collected from food outlets, and MRSA presence was determined using oxacillin resistance screening agar supplemented with polymyxin B and oxacillin. Polymerase chain reaction confirmed and characterized MRSA isolates for virulence potentials and antimicrobial resistance genes. Out of the 400 samples, 57(14.25%) tested positive for MRSA. The prevalence of virulence genes varied, with Panton-Valentine Leukocidin (pvl) detected in 40.51% of isolates, along with the detection of several staphylococcal enterotoxin genes. Antimicrobial resistance genes, including tetracycline (tetM, 43.04%), erythromycin (ermC, 32.91%), and methicillin (mecA, 100%; mecC, 29.11%) were detected. Staphylococcal cassette chromosome mec (SCCmec) typing revealed diverse profiles, with type V being predominant (32.9%). MRSA isolates exhibited resistance to multiple antibiotics, with 83.54% of them classified as multidrug-resistant. Extracellular virulence factors were common, with strong biofilm producers observed in 69.62% of isolates. These findings underscore the complexity of MRSA contamination in RTE foods, highlighting the need for enhanced surveillance and control measures to safeguard public health.
... These nanoparticles represent a promising alternative to conventional antibacterial agents due to their broad-spectrum physicochemical properties, which enable them to act through multiple mechanisms. 8 As illustrated in Figure 9, the antibacterial activity and mechanism of action of CBE-ZnO-NPs are strongly influenced by oxidative stress. These include the disruption of bacterial cell membranes, interference with enzyme pathways, DNA and RNA polymerase inhibition, folic acid disruption, and impairment of protein synthesis. ...
Background and Aim
The rapid advancement of nanotechnology has opened new avenues for biomedical applications, particularly in antimicrobial, anti-inflammatory, and anticancer therapies. Green synthesis of zinc oxide nanoparticles (ZnO-NPs) using plant extracts offers an eco-friendly and biocompatible alternative to traditional chemical methods. This study explores the synthesis of ZnO-NPs using Syzygium aromaticum (clove) bud extract (CBE) and evaluates their multifaceted biomedical potential, including anticancer, antibacterial, and anti-inflammatory properties.
Methods
Clove bud extract-zinc oxide nanoparticles (CBE-ZnO-NPs) were synthesized and characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and Brunauer-Emmett-Teller (BET) analyses to confirm their size, morphology, elemental composition, and surface properties. The anticancer efficacy was tested against tongue carcinoma (HNO-97) cells using the sulforhodamine B (SRB) assay. Antibacterial activity was assessed against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus, while anti-inflammatory potential was evaluated using a mouse macrophage cell line (RAW 264.7).
Results
The SEM analysis confirmed a non-uniform shape of ZnO-NPs, while FTIR revealed functional groups responsible for stabilization and bioactivity. DLS measurements indicated an average particle size of 249.8 nm with a zeta potential of −3.38 mV, ensuring moderate colloidal stability. BET analysis demonstrated a high porosity (30.039 m²/g) and a mean particle size of 19.52 nm. CBE-ZnO-NPs exhibited moderate anticancer activity against tongue carcinoma cells (IC50 > 100 µg/mL), potent antibacterial activity (MIC = 62.5–125 μg/mL), and anti-inflammatory effects (IC50 = 69.3 µg/mL).
Conclusion
This study highlights the potential of CBE-ZnO-NPs as a promising multi-functional nanomaterial with potent antibacterial, anticancer, and anti-inflammatory properties. The findings pave the way for further exploration of ZnO-based nanotherapeutics in biomedical applications, particularly in cancer therapy, infection control, and inflammatory disorders.
... The decrease in decay incidence was probably due to the effect of the coating on delaying senescence, which results in lower pathogenic infections [37]. Additionally, ZnO NPs have antimicrobial effects against several postharvest microbial infections [20][38] [39]. The presence of ZnO NPs within the coating solution serves as a physical barrier on the surface of mangoes. ...
The rise in environmental awareness has led to the development of biopolymers derived from natural sources as a viable alternative to synthetic materials for packaging. Zinc oxide (ZnO) NPs-starch coatings offer an alternative to synthetic materials, but their effectiveness depends on factors like product specifications, environmental implications, and adherence to regulations. The mango industry faces challenges in mitigating and managing diseases that impact mango orchards worldwide. To improve coating properties, zinc oxide (ZnO) and starch are combined to protect mangoes during storage. A study coated mango fruit samples with different concentrations of ZnO solution, and the fruits were stored at ambient temperature for seven days. The ZnO coating significantly preserved mango fruits by delaying fruit senescence, minimising fungal growth, and maintaining sensory quality. Additionally, mangoes coated with 1.5 M ZnO showed reduced weight loss after seven days of storage at room temperature. Field Emission Scanning Electron Microscopy (FESEM) was used to analyze the interaction between ZnO/corn starch coatings and microbes, revealing the physical damages caused by the coating on microbial cells. Thus, ZnO corn starch has improved hydrophobicity and excellent antimicrobial properties in preserving mango quality.
Extensive anthropogenic activity has led to the accumulation of organic and inorganic contaminants in diverse ecosystems, which presents significant challenges for the environment and its inhabitants. Utilizing microalgae as a bioremediation tool can present a potential solution to these challenges. Microalgae have gained significant attention as a promising biotechnological solution for detoxifying environmental pollutants. This is due to their advantages, such as rapid growth rate, cost-effectiveness, high oil-rich biomass production, and ease of implementation. Moreover, microalgae-based remediation is more environmentally sustainable for not generating additional waste sludge, capturing atmospheric CO2, and being efficient for nutrient recycling and sustainable algal biomass production for biofuels and high-value-added products generation. Hence, microalgae can achieve sustainability's three main pillars (environmental, economic, and social). Microalgal biomass can mediate contaminated wastewater effectively through accumulation, adsorption, and metabolism. These mechanisms enable the microalgae to reduce the concentration of heavy metals and organic contaminants to levels that are considered non-toxic. However, several factors, such as microalgal strain, cultivation technique, and the type of pollutants, limit the understanding of the microalgal removal mechanism and efficiency. Furthermore, adopting novel technological advancements (e.g., nanotechnology) may serve as a viable approach to address the challenge of refractory pollutants and bioremediation process sustainability. Therefore, this review discusses the mechanism and the ability of different microalgal species to mitigate persistent refractory pollutants, such as industrial effluents, dyes, pesticides, and pharmaceuticals. Also, this review paper provided insight into the production of nanomaterials, nanoparticles, and nanoparticle-based biosensors from microalgae and the immobilization of microalgae on nanomaterials to enhance bioremediation process efficiency. This review may open a new avenue for future advancing research regarding a sustainable biodegradation process of refractory pollutants.
Chestnut inner shell, cinnamon, and ε-poly-lysine (ε-PL) have been used for natural preservative of food grade, and combined preservatives (CP) has been formulated previously. This study examined whether Staphylococcus aureus growth could be controlled using CP in tryptic soy broth (TSB). CP inhibited S. aureus growth by about 5 log CFU/mL in TSB. The cell surface hydrophobicity, autoaggregation, and motility of S. aureus were slightly reduced by CP treatment. The expression of adhesion- and toxin-related genes in S. aureus treated with CP was reduced than that in the control treated with TSB. In addition, the inhibitory activity of the CP was visible through the SEM images. Therefore, the CP consisted of chestnut inner shell extract, cinnamon extract, and ε-PL had appropriate antibacterial effect against S. aureus and could be applied as antibacterial agents.
The presence of Staphylococcus aureus in six dry-cured meat-processing facilities was investigated. S. aureus was detected in 3.8% of surfaces from five facilities. The occurrence was clearly higher during processing (4.8%) than after cleaning and disinfection (1.4%). Thirty-eight isolates were typified by PFGE and MLST. Eleven sequence types (STs) were defined by MLST. ST30 (32%) and ST12 (24%) were the most abundant. Enterotoxin genes were detected in 53% of isolates. The enterotoxin A gene (sea) was present in all ST30 isolates, seb in one ST1 isolate, and sec in two ST45 isolates. Sixteen isolates harbored the enterotoxin gene cluster (egc) with four variations in the sequence. The toxic shock syndrome toxin gene (tst) was detected in 82% of isolates. Regarding antimicrobial resistance, twelve strains were susceptible to all the antibiotics tested (31.6%). However, 15.8% were resistant to three or more antimicrobials and, therefore, multidrug-resistant. Our results showed that in general, efficient cleaning and disinfection procedures were applied. Nonetheless, the presence of S. aureus with virulence determinants and resistance to antimicrobials, particularly multidrug-resistant MRSA ST398 strains, might represent a potential health hazard for consumers.
Dental caries is an infectious disease that is a major concern for dentists. Streptococci and Lactobacilli were long thought to be the primary etiology responsible for caries. Candida albicans with acidogenic and aciduric characteristics has recently been implicated in the onset and progression of cariogenic lesions. Moreover, due to the increased resistance to common antimicrobials, the discovery of innovative candidates is in high demand. Therefore, our study might be the first report that explores the efficacy of glass ionomer cement (GIC) incorporated with a newly modified carboxylated chitosan derivative (CS-MC) against multidrug-resistant (MDR) and/or pandrug resistant (PDR) C. albicans isolated from the oral cavity. In this work, four CS-MC-GIC groups with different concentrations were formulated. Group four (CS-MC-GIC-4) gave a significant performance as an anticandidal agent against selected PDR Candida strain, with an obvious decrease in its cell viability and high antibiofilm activity. It also, enhanced all the mechanical properties and supports cell viability of Vero cells as a nontoxic compound. Moreover, CS-MC-GIC-4 inhibited neuraminidases completely, which might provide a novel mechanism to prevent dental/oral infections. Thus, findings in this study open up new prospect of the utilization of CS-MC-GIC as a novel dental filling material against oral drug-resistant Candida.
The utilization of living organisms for the creation of inorganic nanoscale particles is a potential new development in the realm of biotechnology. An essential milestone in the realm of nanotechnology is the process of creating dependable and environmentally acceptable metallic nanoparticles. Due to its increasing popularity and ease, use of ambient biological resources is quickly becoming more significant in this field of study. The phrase “green nanotechnology” has gained a lot of attention and refers to a variety of procedures that eliminate or do away with hazardous compounds to repair the environment. Green nanomaterials can be used in a variety of biotechnological sectors such as medicine and biology, as well as in the food and textile industries, wastewater treatment and agriculture field. The construction of an updated level of knowledge with utilization and a study of the ambient biological systems that might support and revolutionize the creation of nanoparticles (NPs) are presented in this article.
Background:
A urinary tract infection (UTI) resulting from multidrug-resistant (MDR) enterococci is a common disease with few therapeutic options. About 15% of urinary tract infections are caused by biofilm-producing Enterococcus spp. Therefore, the objective of this study was to identify the MDR enterococci associated with UTIs and assess their potential to produce biofilms.
Methods:
Thirty Enterococcus isolates were obtained from urine samples collected from UTI patients at King Abdulaziz Specialist Hospital in Taif, Saudi Arabia. The antimicrobial resistance profiles of the isolates were evaluated using disk diffusion techniques against 15 antimicrobial agents. Two techniques, Congo red agar (CRA) and a microtiter plate (MTP), were used to assess the potential of the isolates to produce biofilms. The enterococcal isolates were screened for biofilm-related genes, esp; ebpA; and ebpB, using the PCR method.
Results:
The molecular identification of the collected bacteria revealed the presence of 73.3% Enterococcus faecalis and 26.6% Enterococcus faecium. The antibiotic susceptibility test revealed that all the tested Enterococcus spp. were resistant to all antimicrobials except for linezolid and tigecycline. Additionally, by employing the CRA and MTP techniques, 76.6% and 100% of the Enterococcus isolates were able to generate biofilms, respectively. In terms of the association between the antibiotic resistance and biofilm's formation, it was observed that isolates capable of creating strong biofilms were extremely resistant to most of the antibiotics tested. The obtained data showed that all the tested isolates had biofilm-encoding genes.
Conclusions:
Our research revealed that the biofilm-producing enterococci bacteria that causes urinary tract infections were resistant to antibiotics. Therefore, it is necessary to seek other pharmacological treatments if antibiotic medicine fails.
Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen and frequent colonizer of human skin and mucosal membranes, including the vagina, with vaginal colonization reaching nearly 25% in some pregnant populations. MRSA vaginal colonization can lead to aerobic vaginitis (AV), and during pregnancy, bacterial ascension into the upper reproductive tract can lead to adverse birth outcomes. USA300, the most prominent MRSA lineage to colonize pregnant individuals, is a robust biofilm former and causative agent of invasive infections; however, little is known about how it colonizes and ascends in the female reproductive tract (FRT). Our previous studies showed that a MRSA mutant of seven fibrinogen-binding adhesins was deficient in FRT epithelial attachment and colonization. Using both monolayer and multilayer air-liquid interface cell culture models, we determine that one class of these adhesins, the fibronectin binding proteins (FnBPA and FnBPB), are critical for association with human vaginal epithelial cells (hVECs) and hVEC invasion through interactions with α5β1 integrin. We observe that both FnBPs are important for biofilm formation as single and double fnbAB mutants exhibit reduced biofilm formation on hVECs. Using heterologous expression of fnbA and fnbB in Staphylococcus carnosus, FnBPs are also found to be sufficient for hVEC cellular association, invasion, and biofilm formation. In addition, we found that an ΔfnbAB mutant displays attenuated ascension in our murine vaginal colonization model. Better understanding of MRSA FRT colonization and ascension can ultimately inform treatment strategies to limit MRSA vaginal burden or prevent ascension, especially during pregnancy and in those prone to AV.
Preserving fresh food, such as meat, is significant in the effort of combating global food scarcity. Meat drying is a common way of preserving meat with a rich history in many cultures around the globe. In modern days, dried meat has become a well enjoyed food product in the market because of its long shelf-life, taste and health benefits. This review aims to compile information on how the types of meat, ingredients and the used drying technologies influence the characteristics of dried meat in physicochemical, microbial, biochemical and safety features along with technological future prospects in the dried meat industry. The quality of dried meat can be influenced by a variety of factors, including its production conditions and the major biochemical changes that occur throughout the drying process, which are also discussed in this review. Additionally, the sensory attributes of dried meat are also reviewed, whereby the texture of meat and the preference of the market are emphasized. There are other aspects and concerning issues that are suggested for future studies. It is well-known that reducing the water content in meat helps in preventing microbial growth, which in turn prevents the presence of harmful substances in meat. However, drying the meat can change the characteristics of the meat itself, making consumers concerned on whether dried meat is safe to be consumed on a regular basis. It is important to consider the role of microbial enzymes and microbes in the preservation of their flavor when discussing dried meats and dried meat products. The sensory, microbiological, and safety elements of dried meat are also affected by these distinctive changes, which revolve around customer preferences and health concerns, particularly how drying is efficient in eliminating/reducing hazardous bacteria from the fish. Interestingly, some studies have concentrated on increasing the efficiency of dried meat production to produce a safer range of dried meat products with less effort and time. This review compiled important information from all available online research databases. This review may help the food sector in improving the efficiency and safety of meat drying, reducing food waste, while maintaining the quality and nutritional content of dried meat.
Background
The carbon family nanoparticles are less reviewed for their impact on organisms associated with oxidative stress physiology.
Methods
This review was carried out after collecting literature on the above topic from various sources, including PubMed and Google Scholar.
Results
The carbon family nanoparticles have tissue-specific impacts on various organisms, which are evident at the molecular level.
Conclusion
The carbon nanoparticles and molecules of its family need to be very judiciously released as waste to the environment as they may impart toxic effects on organisms.
The biofabrication of zinc oxide nanoparticles by renewable sources is thought to be ecologically acceptable, clean, and nontoxic. Willow plant (Salix tetrasperma) in the current study was used to measure its ability to create zinc oxide nanoparticles (ZnONPs). The created ZnONPs were characterized via several techniques namely ultraviolet visible (UV–Vis) spectroscopy, transmission electron microscope (TEM), scanning electron microscope (SEM), dynamic light scattering (DLS), atomic force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infra-red (FTIR) spectroscopy, and Raman spectroscopy. Disk diffusion method was applied to assess the antimicrobial activity of ZnONPs. Free radical scavenging potential of different concentrations of ZnONPs and plant extract was measured by 1,1-diphenyl-2-picryl hydrazyl (DPPH) method. Cytotoxicity against prostate cancer cells (Pc3) via the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide)-based assay. Sharp peak was observed at 310 nm indicating the creation of ZnONPs. XRD results and Raman analysis confirmed the natural crystal structure of ZnONPs and stable zinc oxide (ZnO) structure. Good antibacterial activity of ZnONPs was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, and Salmonella typhimurium with inhibition zones 28.10 ± 0.17, 23.83 ± 0.29, 28.33 ± 0.58, 23.83 ± 1.04, 28.33 ± 0.58, and 33.83 ± 0.76 mm, respectively. Candida albicans was also inhibited with inhibition zone 23.67 ± 0.29 mm, while Mucor circinelloide and Aspergillus fumigatus not inhibited by ZnONPs. A promising antioxidant activity of ZnONPs was observed with IC50 8.73 µg/mL compared with the IC50 15.91 µg/mL of the plant extract. Cytotoxicity test indicated the activity of ZnONPs against Pc3.
In this research, we reported for the first time the simple incorporation of antibiotic cefotaxime (CFM) with the synthesized Ag NPs, Se NPs, and bimetallic Ag–Se NPs by gamma rays, as a promising cost-effective, and eco-friendly method. The synthesized nanocomposites were characterized by UV-Vis. spectroscopy, XRD, EDX, HR-TEM, SEM/mapping, and EDX studies. The antimicrobial synergistic potential was investigated after CFM drug incorporation. Antibiofilm activity, growth curve assay, and effect of UV illumination were examined against some pathogenic microbes. The antibacterial reaction mechanism was evaluated by protein leakage assay and SEM imaging. HRTEM imaging confirmed the spherical shape and an average diameter of 10.95, 20.54, and 12.69 nm for Ag NPs, Se NPs, and Ag–Se NPs, respectively. Ag NPs-CFM, Se NPs-CFM, and Ag–Se NPs-CFM possessed antimicrobial activity against Staphylococcus aureus (40, 42, and 43 mm ZOI, respectively), Escherichia coli (33, 35, and 34 mm ZOI, respectively) and Candida albicans (25, 22, and 23 mm ZOI, respectively). CFM-incorporated Ag–Se NPs were able to inhibit biofilm formation of S. aureus (96.09%), E. coli (98.32%), and C. albicans (95.93%). Based on the promising results, the synthesized nanocomposites showed superior antimicrobial potential at low concentrations and continued-phase durability; they may find use in pharmaceutical, and biomedical applications.
Mycosynthesis of nanoparticle (NP) production is a potential ecofriendly technology for large scale production. In the present study, copper oxide nanoparticles (CuONPs) have been synthesized from the live cell filtrate of the fungus Penicillium chrysogenum. The created CuONPs were characterized via several techniques, namely Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the biosynthesized CuONPs were performed against biofilm forming Klebsiella oxytoca ATCC 51,983, Escherichia coli ATCC 35,218, Staphylococcus aureus ATCC 25,923, and Bacillus cereus ATCC 11,778. The anti-bacterial activity result was shown with the zone of inhibition determined to be 14 ± 0.31 mm, 16 ± 0.53 mm, 11 ± 0.57 mm, and 10 ± 0.57 mm respectively. Klebsiella oxytoca and Escherichia coli were more susceptible to CuONPs with minimal inhibitory concentration (MIC) values 6.25 and 3.12 µg/mL, respectively, while for Staphylococcus aureus and Bacillus cereus, MIC value was 12.5 and 25 μg/mL, respectively. The minimum biofilm inhibition concentration (MBIC) result was more evident, that the CuONPs have excellent anti-biofilm activity at sub-MIC levels reducing biofilm formation by 49% and 59% against Klebsiella oxytoca and Escherichia coli, while the results indicated that the MBIC of CuONPs on Bacillus cereus and Staphylococcus aureus was higher than 200 μg/mL and 256 μg/mL, respectively, suggesting that these CuONPs could not inhibit mature formatted biofilm of Bacillus cereus and Staphylococcus aureus in vitro. Overall, all the results were clearly confirmed that the CuONPs have excellent anti-biofilm ability against Klebsiella oxytoca and Escherichia coli. The prepared CuONPs offer a smart approach for biomedical therapy of resistant microorganisms because of its promoted antimicrobial action, but only for specified purposes.
Green synthesis of zinc oxide nanoparticles (ZnO NPs) using plant extracts have recently attracted considerable attention due to their environmental protection benefits and their easy and low cost of fabrication. In the current study, ZnO NPS were synthesized using the aqueous extract of Ochradenus arabicus as a capping and reducing agent. The obtained ZnO NPs were firstly characterized using ultraviolet visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR), transmission electron microscope (TEM), X-ray diffraction (XRD), energy dispersive X-ray absorption (EDX), zeta potential, and zeta size. All these techniques confirmed the characteristic features of the biogenic synthesized ZnO NPs. Then, ZnO NPs were evaluated for their effects on morphological, biochemical, and physiological parameters of Salvia officinalis cultured in Murashige and Skoog medium containing 0, 75, 100, and 150 mM of NaCl. The results showed that ZnO NPs at a dose of 10 mg/L significantly increased the shoot number, shoot fresh weight, and shoot dry weight of Salvia officinalis subjected or not to the salt stress. For the shoot length, a slight increase of 4.3% was recorded in the plant treated by 150 mM NaCl+10 mg/L ZnO NPs compared to the plant treated only with 150 mM of NaCl. On the other hand, without NaCl, the application of both concentrations 10 mg/L and 30 mg/L of ZnO NPs significantly improved the total chlorophyll content by 30.3% and 21.8%, respectively. Under 150 mM of NaCl, the addition of 10 mg/L of ZnO NPs enhanced the total chlorophyll by 1.5 times, whilst a slight decrease of total chlorophyll was recorded in the plants treated by 150 mM NaCl + 30 mg/L ZnO NPs. Additionally, ZnO NPs significantly enhance the proline accumulation and the antioxidative enzyme activities of catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) in plants under salinity. Our findings revealed that green synthesized ZnO NPs, especially at a dose of 10 mg/L, play a crucial role in growth enhancement and salt stress mitigation. Hence, this biosynthesized ZnO NPs at a concentration of 10 mg/L can be considered as effective nanofertilizers for the plants grown in salty areas.
Street vended food businesses play economic and social roles in developing countries through provision of employment, availability of food at affordable prices, and accessibility of wide range of food choices that suits different social communities and classes. Mobile, semi-mobile or fixed carts are used by street food vendors comprising of men and women of all age groups. However, due to the informal nature of street food vending business, it is often neglected by regulatory authorities, resulting in unwholesome practices. Poor infrastructure, lack of sanitation, and improper personal hygiene are associated with microbial hazards, environmental pollution, and chemical contamination, all which contribute to a high risk of foodborne diseases and health hazards. In order to prevent street foods contamination, vendors require hygiene training and access to approved and audited facilities that may ensure food safety. Government should take effective steps through legislation and conduct food safety training programs. Active collaboration between regulatory bodies and NGOs is crucial to support street vendors with proper enforcement of public health policies. Safe food handling practices can improve the food safety and quality as well as improve the health of both food vendors and consumers in developing countries.
In this study, a novel, non-toxic, eco-friendly zinc oxide nanoparticles (ZnO-NPs) was used instead of the synthetic fungicides widely used to control the destructive phytopathogenic fungus Fusarium oxysporum, the causative agent of wilt disease in Solanum melongena L. Herein, the biosynthesized ZnO-NPs was carried out by Penicillium expansum ATCC 7861. In vitro, mycosynthesized ZnO-NPs exhibited antifungal activity against Fusarium oxysporum. In vivo, ZnO-NPs suppressed Fusarium wilt disease in cultivated Solanum melongena L. by decreasing the disease severity with 75% of plant protection. Moreover, ZnO-NPs stimulated the recovery of eggplant as an indicated by improving of morphological and metabolic indicators including plant height(152.5%), root length(106.6%), plant fresh biomass (146%), chlorophyll a (102.8%), chlorophyll b (67.86%), total soluble carbohydrates (48.5%), total soluble protein (81.8%), phenol (10.5%), antioxidant activity and isozymes compared with infected control. Therefore, this study suggests using mycosynthesized ZnO-NPs as an alternative to synthetic fungicides not only to eradicate the Fusarium wilt disease in cultivated eggplant (Solanum melongena) but also to promote the growth parameters and metabolic aspects.
Thirty-one of sixty dyspeptic patients tested positive for Helicobacter pylori colonization in this study, as determined by histopathology and 16S rRNA. The cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA) genes were found in 67.7 and 93.5% of H. pylori patients, respectively. The cagA gene was found to be associated with 100% of patients with duodenal erosion and ulceration identified via endoscopy examination. In addition, 86.7% of patients with cancerous and precancerous lesions, glandular atrophy, and intestinal metaplasia identified via histopathology examination. The vacA s1m1 mutation was associated with more severe forms of gastric erosion and ulceration, as well as the presence of precancerous and cancerous lesions. Eighteen (64.3%) of the twenty-eight isolates were classified as multi-drug resistant (MDR) or pan-drug resistant (PDR) H. pylori. Due to a resurgence of interest in alternative therapies derived from plants as a result of H. pylori resistance to the majority of commonly used antibiotics, the inhibitory activity of five essential oils extracted from some commonly used medicinal plants was evaluated in vitro against drug-resistant H. pylori clinical isolates. Cinnamomum zeylanicum essential oil demonstrated the highest anti-H. pylori activity when compared to the other essential oils tested. Cinnamaldehyde was the most abundant compound in C. zeylanicum (65.91%). The toxicological evaluation established the safety of C. zeylanicum oil for human use. As a result, C. zeylanicum essential oil may represent a novel antibacterial agent capable of combating drug-resistant H. pylori carrying cytotoxin genes.
Staphylococcus aureus causes a foodborne intoxication due to the production of enterotoxins and shows antimicrobial resistance, as in the case of methicillin-resistant strains (MRSA). Herein, we analyzed 207 ready-to-eat foods collected in Algeria, reporting a S. aureus prevalence of 23.2% (48/207) and respective loads of coagulase positive staphylococci (CPS) ranging from 1.00 ± 0.5 to 5.11 ± 0.24 Log CFU/g. The 48 S. aureus isolates were widely characterized by staphylococcal enterotoxin gene (SEg)-typing and 16S-23S rDNA intergenic spacer region (ISR)-PCR, as well as by detecting tst and mecA genes, genetic determinants of toxic shock syndrome toxin-1 and methicillin resistance, respectively. We found that the S. aureus isolates belonged to seven different SEg-types harboring the following combinations of genes: (1) selW, selX; (2) egc (seG, seI, seM, seN, seO), selW, selX; (3) seA, seH, seK, seQ, selW, selX; (4) seB, selW, selX; (5) seD, selJ, seR, selW, selX; (6) seH, selW, selX, selY; and (7) seA, egc, selW, selX, while among these, 2.1% and 4.2% were tst- and mecA- (staphylococcal chromosomal cassette mec-type IV) positive, respectively. Selected strains belonging to the 12 detected ISR-types were resistant towards antimicrobials including benzylpenicillin, ofloxacin, erythromycin, lincomycin, tetracyclin, kanamycin, oxacillin, and cefoxitin; 8.3% (1/12) were confirmed as MRSA and 16.7% (2/12) were multidrug resistant. The present study shows the heterogeneity of the S. aureus population in Algerian ready-to-eat foods as for their toxigenic potential and antimicrobial resistance, shedding the light on the quality and safety related to the consume of ready-to-eat foods in Algeria.
Zinc oxide nanoparticles (ZnO-NPs) have gained attention due to their distinctive properties and applications. In the current study, we developed an eco-friendly, economical, and green route for the synthesis of ZnO-NPs using the aqueous extract of the brown marine alga Cystoseira crinita (Fucales; Sargassaceae). ZnO-NPs were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The antimicrobial and antioxidant activities were investigated. The UV absorption peaks at 268 nm and 360 nm confirm the formation of ZnO-NPs., and XRD patterns indicated the crystalline nature of ZnO-NPs. The TEM revealed that the size of ZnO-NPs was ranged between 23 to 200 nm corresponding to DLS, while the shape is multilayered rectangular particles. FTIR analysis revealed that phenolic compounds and proteins were the reducing and capping agents. ZnO-NPs showed antimicrobial activities against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus niger, furthermore, showed moderate DPPH radical-scavenging activity.
The dearth of new medicines effective against antibiotic-resistant bacteria presents a growing global public health concern¹. For more than five decades, the search for new antibiotics has relied heavily on the chemical modification of natural products (semisynthesis), a method ill-equipped to combat rapidly evolving resistance threats. Semisynthetic modifications are typically of limited scope within polyfunctional antibiotics, usually increase molecular weight, and seldom permit modifications of the underlying scaffold. When properly designed, fully synthetic routes can easily address these shortcomings². Here we report the structure-guided design and component-based synthesis of a rigid oxepanoproline scaffold which, when linked to the aminooctose residue of clindamycin, produces an antibiotic of exceptional potency and spectrum of activity, which we name iboxamycin. Iboxamycin is effective against ESKAPE pathogens including strains expressing Erm and Cfr ribosomal RNA methyltransferase enzymes, products of genes that confer resistance to all clinically relevant antibiotics targeting the large ribosomal subunit, namely macrolides, lincosamides, phenicols, oxazolidinones, pleuromutilins and streptogramins. X-ray crystallographic studies of iboxamycin in complex with the native bacterial ribosome, as well as with the Erm-methylated ribosome, uncover the structural basis for this enhanced activity, including a displacement of the nucleotide upon antibiotic binding. Iboxamycin is orally bioavailable, safe and effective in treating both Gram-positive and Gram-negative bacterial infections in mice, attesting to the capacity for chemical synthesis to provide new antibiotics in an era of increasing resistance.
In addition to the benefits, increasing the constant need for antibiotics has resulted in the
development of antibiotic bacterial resistance over time. Antibiotic tolerance mainly evolves in these
bacteria through efflux pumps and biofilms. Leading to its modern and profitable uses, emerging
nanotechnology is a significant field of research that is considered as the most important scientific
breakthrough in recent years. Metal nanoparticles as nanocarriers are currently attracting a lot of
interest from scientists, because of their wide range of applications and higher compatibility with
bioactive components. As a consequence of their ability to inhibit the growth of bacteria, nanoparticles have been shown to have significant antibacterial, antifungal, antiviral, and antiparasitic efficacy in the battle against antibiotic resistance in microorganisms. As a result, this study covers bacterial tolerance to antibiotics, the antibacterial properties of various metal nanoparticles, their mechanisms, and the use of various metal and metal oxide nanoparticles as novel antibiotic carriers for
direct antibiotic delivery.
The aim of this study was to evaluate and characterize the bacterial load present in twenty-four Ready-To-Eat (RTE) sandwiches, purchased at refrigerated vending machines and supermarkets in the province of Modena (Italy). We isolated 54 bacterial strains, including pathogens of interest in food safety, such as Listeria, Staphylococcus, Enterococcus, Yersinia, Aeromonas and Acinetobacter spp. Phenotypic tests have been performed on these pathogens to detect the presence of virulence factors, such as gelatinase production and hemolytic capability. To test their antibiotic resistance features, the minimum inhibitory concentration (MIC) against eight commonly used antibiotics (Amikacin, Ciprofloxacin, Ampicillin, Oxacillin, Imipenem, Tetracycline, Erythromycin and Vancomycin) was also evaluated. The results showed that among the 54 isolates, fifty percent (50%) belonged to harmless microorganisms (Leuconostoc and Lactococcus), whereas the remaining fifty percent (50%) included pathogenic bacteria (Listeria ivanovii, Listeria monocytogenes, Staphylococcus aureus, Yersinia, and Citrobacter spp.), species responsible for pathologies often difficult to treat due to the presence of antibiotic resistance features. This study demonstrates the importance of thorough controls, both during the production and marketing of RTE food like sandwiches, to avoid reaching the infectious load and the onset of pathologies, particularly dangerous for old and immunocompromised patients.
Green synthesis of zinc oxide nanoparticles (ZnO NPs) through simple, rapid, eco-friendly and an economical method with a new haloalkaliphilic bacterial strain ( Alkalibacillus sp. W7) was investigated. Response surface methodology (RSM) based on Box-Behnken design (BP) was used to optimize the process parameters (ZnSO 4 .7H 2 O concentration, temperature, and pH) affecting the size of Alkalibacillus -ZnO NPs (Alk-ZnO NPs). The synthesized nanoparticles were characterized using UV–visible spectrum, X-ray diffraction (XRD), Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM–EDX), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Zeta potential. The UV–Vis spectrum of ZnO NPs revealed a characteristic surface plasmon resonance (SPR) peak at 310 nm. XRD pattern confirmed the hexagonal wurtzite structure of highly pure with a crystallite size 19.5 nm. TEM proved the quasi-spherical shape nanoparticles of size ranging from 1 to 30 nm. SEM–EDX showed spherical shaped and displayed a maximum elemental distribution of zinc and oxygen. FTIR provided an evidence that the biofunctional groups of metabolites in Alkalibacillus sp.W7 supernatant acted as viable reducing, capping and stabilizing agents.
Donor human milk (HM) obtained at HM banks is exceptionally crucial for the feeding and treatment of preterm infants. Bacterial contaminations of HM in various stages of its handling are very common and can lead to disqualification of donations or severe infections in worse cases. Hence, HM donations are subject to strict bacteriological evaluations pre- and post-pasteurization. The main contaminating species vary between countries, banks and donors and even exhibit inter-individual variation. We initiated an assessment of the bacteriological composition of HM donated by women hospitalized in a neonatal intensive care unit in Israel. The most common bacterium identified was Staphylococcus epidermidis, found in all but one of the HM samples; the presence of several species of coagulase-negative Staphylococci was also noted. Next, we sought to develop a platform towards antibacterial treatment using Zn2+ ions that have recently been found to be potent against contaminants isolated from bovine milk. Zn2+ efficiently inhibited the growth of viable aerobic population and S. epidermidis in HM. Growth was also inhibited in other Gram-positive bacteria such as Bacillus cereus, a well-known food-borne pathogen. S. epidermidis and B. cereus cells grown in the presence of zinc were taken for microscopic evaluation, aiming to demonstrate zinc’s antimicrobial mode of action morphologically. Images obtained using scanning electron microscopy indicated leakage of cellular content and cell lysis in S. epidermidis. Besides, B. cereus cells showed abnormalities in their cell surface and complete loss of flagella upon treatment with zinc. Along with the above findings, it should be noted that this was a pilot study that tested how high doses of Zn2+ affect breast milk as a product. Further research is likely needed on the safety of consumption of Zn2+-treated HM in infants and older children.
Consumption of food that is contaminated by microorganisms, chemicals, and toxins may lead to significant morbidity and mortality, which has negative socioeconomic and public health implications. Monitoring and surveillance of microbial diversity along the food value chain is a key component for hazard identification and evaluation of potential pathogen risks from farm to the consumer. The aim of this study was to determine the microbial diversity in meat and meat products from different enterprises and meat types in South Africa. Samples (n = 2017) were analyzed for Yersinia enterocolitica, Salmonella species, Listeria monocytogenes, Campylobacter jejuni, Campylobacter coli, Staphylococcus aureus, Clostridium perfringens, Bacillus cereus, and Clostridium botulinum using culture-based methods. PCR was used for confirmation of selected pathogens. Of the 2017 samples analyzed, microbial ecology was assessed for selected subsamples where next generation sequencing had been conducted, followed by the application of computational methods to reconstruct individual genomes from the respective sample (metagenomics). With the exception of Clostridium botulinum, selective culture-dependent methods revealed that samples were contaminated with at least one of the tested foodborne pathogens. The data from metagenomics analysis revealed the presence of diverse bacteria, viruses, and fungi. The analyses provide evidence of diverse and highly variable microbial communities in products of animal origin, which is important for food safety, food labeling, biosecurity, and shelf life limiting spoilage by microorganisms.
This study was conducted to assess the level of food safety knowledge, attitudes and practices among 273 Filipinos, Egyptians and Indians food handlers in Kuwait restaurants. The information was obtained through face to face interviews and questionnaires covering four sections: demographic characteristics, food safety knowledge, attitudes and practices. The results show that Filipinos, Egyptians and Indians food handlers had sufficient food safety knowledge particularly in the personal hygiene area. Filipinos were the best answering questions related to cross contamination and sanitation (p < 0.05). Egyptians and Indians lacked the knowledge about cross-contamination and sanitation, time and temperature control for food, and food pathogens. For attitudes, results show that Filipinos had excellent positive attitudes followed by Indians then Egyptians (p < 0.05). The three nationalities generally show very good practices mainly in personal hygiene. However, only 56 % of Egyptians and 57% of Indians avoided keeping cooked food in the temperature danger zone until served (p < 0.05). The study recommends that some aspects associated to cross-contamination, food pathogens and time and temperature control need to be stressed especially for Egyptians and Indians food handlers. Continuous food safety training for food handlers in Kuwait should become compulsory to reinforce food handlers in the areas which seem to be lacking.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen and a historically emergent zoonotic pathogen with public health and veterinary importance. In humans, MRSA commonly causes severe infectious diseases, including food poisoning, pyogenic endocarditis, suppurative pneumonia, otitis media, osteomyelitis, and pyogenic infections of the skin, soft tissues. In the horse, MRSA could cause a localized purulent infection and botryomycosis; in cattle and ewe, localized pyogenic infection and severe acute mastitis with marked toxemia; in sheep, abscess disease resembles caseous lymphadenitis caused by anaerobic strains; in dogs and cats, pustular dermatitis and food poisoning; in pig, exudative epidermatitis “greasy pig disease; in birds, MRSA causes bumble-foot. The methicillin resistance could be determined by PCR-based detection of the mecA gene as well as resistance to cefoxitin. In Egypt, MRSA is one of the important occasions of subclinical and clinical bovine mastitis, and the prevalence of MRSA varies by geographical region. In this review, we are trying to illustrate variable data about the host susceptibility, diseases, epidemiology, virulence factors, antibiotic resistance, treatment, and control of MRSA infection.
Objectives:
This review summarizes the literature on the role of virulence and antimicrobial resistance genes of Staphylococcus aureus in bovine mastitis, focusing on the association between these characteristics and their implications for public and animal health.
Conclusions:
There is the possibility of antimicrobial resistance gene exchange among different bacteria, which is of serious concern in livestock husbandry, as well as in the treatment of human staphylococcal infections.
ARTICLE INFO ABSTRACT Keywords Although Staphylococcus aureus (S. aureus) is a bacterium that remains widely studied because of its high pathogenic potential and its ability to develop resistance to antibiotics routinely used in clinical practice; this study investigated the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in some ready to eat (RTE) meat products collected from some public restaurants and street vendors in Benha city, Qalubiya governorate, Egypt; a total of 120 RTE beef products represented by kofta, burger, shawerma, and luncheon (30 of each) were examined for the prevalence of S. aureus and molecular detection of MRSA strains represented by the presence of mecAgene containing isolates; results revealed that kofta was the most contaminated samples with S. aureus where the mean count was 5.2x10 CFU\g; followed by burger, shawerma and luncheon samples. Molecular detection of MRSA isolates carrying mecA gene revealed that out of eight examined isolates, 2(25%) of examined isolates were MRSA strain. The presence of S. aureus especially MRSA strains in high prevalence among examined RTE meat products emphasizes the necessity of enforcing application of strict hygienic measures and GMP during preparation, handling, and serving; in addition, the health authorities have to exert more control over street vendors and fast food restaurants.. Benha city Meat products MRSA PCR Ready to Eat
Methicillin‐resistant Staphylococcus aureus (MRSA) is resistant to most β‐lactams due to the expression of an extra penicillin‐binding protein, PBP2a, with low β‐lactam affinity. It has long been known that heterologous expression of the PBP2a‐encoding mecA gene in methicillin‐sensitive S. aureus (MSSA) provides protection towards β‐lactams, however, some reports suggest that the degree of protection can vary between different β‐lactams. To test this more systematically, we introduced an IPTG‐inducible mecA into the MSSA laboratory strain RN4220. We confirm, by growth assays as well as single‐cell microfluidics time‐lapse microscopy experiments, that PBP2a expression protects against β‐lactams in S. aureus RN4220. By testing a panel of ten different β‐lactams, we conclude that there is also a great variation in the level of protection conferred by PBP2a. Expression of PBP2a resulted in an only fourfold increase in minimum inhibitory concentration (MIC) for imipenem, while a 32‐fold increase in MIC was observed for cefaclor and cephalexin. Interestingly, in our experimental setup, PBP2a confers the highest protection against cefaclor and cephalexin—two β‐lactams that are known to have a high specific affinity toward the transpeptidase PBP3 of S. aureus. Notably, using a single‐cell microfluidics setup we demonstrate a considerable phenotypic variation between cells upon β‐lactam exposure and show that mecA‐expressing S. aureus can survive β‐lactam concentrations much higher than the minimal inhibitory concentrations. We discuss possible explanations and implications of these results including important aspects regarding treatment of infection. PBP2a confers resistance to β‐lactam antibiotics in Staphylococcus aureus. We expressed the gene encoding PBP2a in a β‐lactam sensitive strain of S. aureus. We found that the resistance level conferred by PBP2a varies considerably between β‐lactams and between single cells in a population.
The green synthesis of nanoparticles (NPs) using living cells is a promising and novelty tool in bionanotechnology. Chemical and physical methods are used to synthesize NPs; however, biological methods are preferred due to its eco-friendly, clean, safe, cost-effective, easy, and effective sources for high productivity and purity. High pressure or temperature is not required for the green synthesis of NPs, and the use of toxic and hazardous substances and the addition of external reducing, stabilizing, or capping agents are avoided. Intra- or extracellular biosynthesis of NPs can be achieved by numerous biological entities including bacteria, fungi, yeast, algae, actinomycetes, and plant extracts. Recently, numerous methods are used to increase the productivity of nanoparticles with variable size, shape, and stability. The different mechanical, optical, magnetic, and chemical properties of NPs have been related to their shape, size, surface charge, and surface area. Detection and characterization of biosynthesized NPs are conducted using different techniques such as UV–vis spectroscopy, FT-IR, TEM, SEM, AFM, DLS, XRD, zeta potential analyses, etc. NPs synthesized by the green approach can be incorporated into different biotechnological fields as antimicrobial, antitumor, and antioxidant agents; as a control for phytopathogens; and as bioremediative factors, and they are also used in the food and textile industries, in smart agriculture, and in wastewater treatment. This review will address biological entities that can be used for the green synthesis of NPs and their prospects for biotechnological applications.
Coagulase-positive Staphylococci (CoPS) can exist as commensals in humans, companion and food-producing animals, but can cause severe or even lethal diseases. Exchange of these bacteria between humans and animals has been described. Special attention has been focused on Methicillin-Resistant Staphylococcus aureus, but other CoPS can also represent an important threat. In addition to significant antimicrobial resistance, these bacteria may carry a plethora of virulence factors - molecules that allow bacteria to establish on or within a host and increase their ability to cause disease. These virulence factors have been widely described in S. aureus but information about other species of CoPS is scarce. The aim of this paper is to review the recent literature about the virulence factors of non-aureus CoPS of animal origin. Their possible effects on human health are also described. The role and prevalence of different virulence factors including leukocidins, hemolysins, adhesins, enterotoxins, exfoliative and toxic shock syndrome toxins as well as superantigen-like proteins are addressed. The effect of these virulence factors on human health is also described. The possibility of misdiagnosis of species of CoPS has been demonstrated in human clinical samples. Prevalence of zoonotic infections could be higher than thought and medical laboratories should be aware of these other staphylococcal species. In keeping with the ‘One Health’ approach to animal and human disease, medical professionals, veterinarians and health workers should be aware of the risks derived from exposure to these bacteria in people in close contact with animals, including pet owners, farmers and veterinarians themselves.
Packaging of food products is one of the most important stages of the food supply chain. Nano-size materials for packing food substances with appropriate properties result in better packaging performance and longer food shelf-life. In this review, the application of ZnO nano-size in active packaging of foods is discussed to identify gaps in applications for food packaging and safety. First, the crystal structures and morphologies of modified ZnO nanoparticles (ZnO NPs) are presented, and their synergistic effects on antimicrobial activities are discussed. This review also provides an overview of antimicrobial packaging containing ZnO NPs with a focus on preparation methods, antimicrobial mechanisms, and recent progress in packaging applications. The generation of reactive oxygen species (ROS) is the primary antimicrobial mechanism, which can be varied depending on morphology and size. Generally, ZnO NPs can inactivate fungi or Gram-positive and Gram-negative bacteria growth, which reduce the risk of cross-contamination, thereby extending the shelf life of products. Notably, the health concerns and hazards regarding the safety and migration of ZnO NPs application are also elaborated. Unintentional migration, inhalation, skin penetration, and ingestion may result in human health hazards. Therefore, to provide safety regulations, further investigations such as case by case study are recommended.
Ready‐to‐eat foods (RTEs) are foods consumed without any further processing. They are widely consumed as choice meals especially by school‐aged children and the fast‐paced working class in most low‐ and middle‐income countries (LMICs), where they contribute substantially to the dietary intake. Depending on the type of processing and packaging material, RTEs could be industrially or traditionally processed. Typically, RTE vendors are of low literacy level, as such, they lack knowledge about good hygiene and food handling practices. In addition, RTEs are often vended in outdoor environments such that they are exposed to several contaminants of microbial origin. Depending on the quantity and type of food contaminant, consumption of contaminated RTEs may result in foodborne diseases and several other adverse health effects in humans. This could constitute major hurdles to growth and development in LMICs. Therefore, this review focuses on providing comprehensive and recent occurrence and impact data on the frequently encountered contaminants of microbial origin published in LMICs within the last decade (2009 to 2018). We have also suggested viable food safety solutions for preventing and controlling the food contamination and promoting consumer health.
The number of infections caused by antibiotic resistant bacteria is rising worldwide. Fish from multisource pollution waters can harbour multidrug-resistant bacteria that can be disseminated to humans through eating or contact of contaminated fish. A cross-sectional study was carried out to (i) isolate and phenotypically identify bacteria from 36 fish samples from informal market in Mufakose, Harare, and (ii) determine the antibiotic sensitivity pattern of the isolated bacteria against ten available antibiotics (ampicillin 10 μ g, gentamycin 30 μ g, penicillin G 10 μ g, erythromycin 15 μ g, tetracycline 30 μ g, kanamycin 30 μ g, neomycin 10 μ g, cloxacillin 5 μ g, lincomycin 15 μ g, and sulfamethoxazole 25 μ g) using the Kirby–Bauer disk agar diffusion method. Eight bacterial genera were isolated and identified, and they were Escherichia , Aeromonas , Staphylococcus , Pseudomonas , Citrobacter , Klebsiella , Enterobacter , and Proteus . Among the isolates, Escherichia coli was isolated most frequently (44%) followed by Staphylococcus aureus (19%), Enterobacter aerogenes (7%), Aeromonas spp. (5%), Proteus mirabilis (5%), Citrobacter (5%), and coagulase-negative Staphylococci (5%) and the least frequent were Klebsiella (3%) and Pseudomonas (3%). All isolates were susceptible to gentamycin. Varying antibiotic resistance rates were observed to lincomycin (100%), ampicillin (81%), penicillin (67%), erythromycin (65%), tetracycline (63%), neomycin (61%), cloxacillin (43%), kanamycin (24%), and sulphamethoxazole (13%). All the isolates were multidrug-resistant (resistant to at 3 or more drugs tested) except Proteus mirabilis . Proteus mirabilis has multiple antibiotic resistance (MAR) index of 0.2, and the other isolated bacteria had MAR indexes greater than 0.2 ranging from 0.3 to 0.7. Those MAR indexes above 0.2 showed that the bacteria isolates are from a high risk source where antibiotics were frequently used, possibly from sewage effluents. Isolation of enteric bacteria such as Escherichia coli is an indication of faecal contamination, and this poses a high risk to animal and human health. These significant findings call for effective risk assessment models and management plans that protect human, animal, and environmental health.
Street foods play important socioeconomic and cultural roles and are popular worldwide. In addition to providing convenient and low-cost meals for urban populations, street food offers an essential source of income for vendors, especially women, and it can reflect traditional local culture, which is an important attraction for tourists. Despite these benefits, the microbiological safety of street food has become a worldwide concern because it is often prepared and sold under inadequate safety conditions, without legal control and sanitary surveillance. Consequently, high counts of fecal indicator bacteria and several foodborne pathogens have been detected in street foods. This review provides insight into the microbiology of street food, focus on the associated microbiological safety aspects and main pathogens, and the global status of this important economic activity. Furthermore, the need to apply molecular detection rather than traditional culture-based methods is discussed to better understand the actual risks of microbial infection associated with street foods. Recognition is always the first step toward addressing a problem.
Food and aquaculture industries are at risk from pathogenic bacteria. Pathogenic bacteria can contaminate food at any step in the supply chain and cause huge damage to both the food and aquaculture systems worldwide. Antibiotics, disinfectants, and feed additives are all routinely employed as microbial control measures. However, owing to their limitations like the development of resistance, limited effectiveness, high expense, and the negative impacts on food, health, and the environment, novel techniques to combat bacterial infections are desperately needed. Bacteriocins represent a possible option due to a varied range of molecular and biochemical features, as well as a wide range of activities with distinct mechanisms of action. This review highlights the importance of bacteriocins as next-generation antimicrobial agents and substitutes for antibiotics in food and aquaculture systems. It further throws light on the various approaches to improving the efficacy of these natural antimicrobial players. This study will emphasize readers to cogitate on the novel ways of preventing spoilage microbes and pathogens in aquaculture and food systems through natural approaches, thus preventing huge wastage in these two main domains.
Polymeric goods have been instrumental due to its versatility, properties like hygienic, lightweight, flexible, and highly durable and hence it accounts for the largest usage of applications worldwide in sectors like electrical, electronic, packaging, automotive, energy generation, furniture, marine, aerospace, military, consumer goods, construction, medical and healthcare, and so forth. However, as the demand for consumer goods continues to grow—from smartphones, smart watches to automobiles, home appliances, food packaging, pharmacy, and so forth; disease transmission (especially during the outbreak of epidemic/pandemic) via tangibility has emerged as a major hurdle to cater the out breaking microbial transmission through touch. The surfaces of these goods/products are required to suffice antimicrobial properties to prevent such contagious surface transmission. Considering the current challenges and need for antimicrobial polymer, a review is presented to collectively enlist the theoretical fundamental; commercial, R&D activities, economic performance, and challenges on large‐scale practice of antimicrobial polymeric products. The review also enumerates the potential antimicrobial nanofillers used for the fabrication of polymer nanocomposites with biostatic and biocidal properties along with expected property enhancement.
Staphylococcus aureus is a commensal bacterium known to colonize the skin, nares, and gastrointestinal tract of humans. Asymptomatic workers can contaminate food via manual contact or through respiratory secretions thus becoming the source of staphylococcal food poisoning. This gastrointestinal intoxication occurs after the ingestion of food contaminated by enterotoxin-producing Staphylococcus aureus. Although most individuals overcome the infection without medical assistance and make a full recovery, in rare cases the infection can be life-threatening. Hence, Staphylococcus aureus food contamination represents a serious problem for both the food industry and healthcare systems. In the last few decades, many studies have investigated the prevalence of carriers among food handlers. We present an overview of all investigations carried out on nasal carriers working in different food industry settings highlighting the risk associated with cross-contamination.
Many metallic NPs, such as silver, copper, zinc, and gold NPs, have been used in food products as preservative packaging material. Zinc oxide (ZnO) NPs are generally recognized as safe (GRAS) by the US FDA and are effective against many microbes. ZnO NPs not only have antimicrobial properties but also support the activity of other antibiotics, such as vancomycin and others. ZnO NPs can be prepared by a mechanochemical process or physical vapor synthesis. The size of the NPs depends on the method used: in mechanochemical processes the size of the NPs is 20–30 nm, whereas it is 8–75 nm in physical vapor synthesis. ZnO NPs have been used as preservatives in food packaging materials. The exact antimicrobial mechanism of ZnO NPs is not well known; however, it has been theorized that ZnO NPs lyse the cell wall of microbes. The antimicrobial potential, GRAS status, and nutritional importance as a source of zinc nutrient have encouraged the use of ZnO NPs in food and feed applications.
Waterborne diseases caused by pathogenic microorganisms pose severe threats to human health. ZnO nanoparticles (NPs) hold great potentials as an effective, economical and eco-friendly method for water disinfection, but the exact antimicrobial mechanism of ZnO NPs under visible-light illumination is still not clear. Herein, we investigate the visible-light-driven photocatalytic inactivation mechanism of amino-functionalized hydrophilic ZnO (AH-ZnO) NPs against Staphylococcus aureus (S. aureus) in aqueous environment from the perspective of electron transfer theory. The results show that the antibacterial effects of AH-ZnO NPs are dependent on the AH-ZnO NPs concentration and treatment time. The bulk ORP value and released Zn²⁺ concentration in AH-ZnO NPs solutions increase with AH-ZnO NPs concentration. The SEM and intracellular protein leakage results indicate that AH-ZnO NPs can adhere to S. aureus surface without causing obvious cell membrane disruption. The photoluminescence (PL) intensity and fluorescence lifetime of AH-ZnO NPs are remarkedly decreased after adding S. aureus, which confirms the electron transfer from S. aureus to AH-ZnO NPs. Moreover, the ΔPL intensity is closely correlated with the inactivation efficiency, demonstrating that the interfacial electron transfer in S. aureus/AH-ZnO NPs composites contributes to the antibacterial activity, which is speculated to disrupt the normal respiratory electron transfer chain of S. aureus, thereby causing intracellular ROS generation, cell membrane depolarization and eventually apoptosis-like death.
Zinc oxide (ZnO) nanoparticles (NPs) are gaining more interest due to their multifunctional and biological properties. Herein, we synthesized ZnO NPs and characterized their optical and electrical properties for application in catalysis and optoelectronic devices and potential biomedical applications. The synthesis of ZnO NPs was performed via a precipitation method, and their crystallinity, crystal structure, crystal phase purity, particle morphology, and size distribution were characterized via X-ray diffraction and transmission electron micrographs. The crystal ligand environment, chemical purity and chemical oxidation states were studied by Raman, infrared and X-ray photoelectron spectroscopy. Thermal stability and residual matter decomposition were studied by thermogravimetric analysis. Furthermore, the optical energy band gap was investigated by UV-Vis absorbance spectroscopy. Similarly, the photocatalytic properties were also studied by rhodamine B degradation under UV light irradiation. Biological activities, such as antibacterial and cytotoxicity potentials, were explored. The synthesized ZnO crystallized in a hexagonal wurtzite structure with an average crystallite diameter of 43 nm. Various anion ligands around Zn²⁺ in wurtzite were confirmed. The sample showed a 3.26 eV optical energy gap with a high photocatalytic activity of 99.5% in 70 min. The synthesized NPs showed high antibacterial activity against Pseudomonas aeruginosa and less cytotoxicity to kidney cancer cell lines (A498). From this finding, we suggest that the prepared ZnO NPs could be used for various biomedical applications.
Methicillin-resistant S. aureus (MRSA) and their antimicrobial resistance pose exacerbating global health threats and endangering everyone. Thus, the prevalence, molecular characterization of virulence genes, and antimicrobial resistance patterns of strains isolated from 225 beef burger and hot dog sandwiches vended in Mansoura city, Egypt were determined. 83.1% of the sandwiches tested were contaminated with coagulase-positive S. aureus, with a mean count of 4×10³ CFU/g. Genes encoding mecA, α-hemolysin, staphylococcal enterotoxins, and toxic shock syndrome toxin-1 were detected in 22.6%, 96.9%, 61.1%, and 0% of the strains isolated, respectively. Of the 190 coagulase-positive strains, 43 (22.6%) were confirmed as MRSA. Amongst them, 4 strains (2.1%) were vancomycin-resistant S. aureus (VRSA) and resistant to all antimicrobials tested. Interestingly, all isolates were resistant to at least one of the tested antimicrobials, with 75.2% being multi-drug resistant (MDR) and an average multiple antimicrobial resistance (MAR) index of 0.503. Not less important, 100%, 96.3%, 90.5%, 79.5%, 73.7%, 62.6%, and 48.9% of isolates were resistant to Kanamycin, Nalidixic acid, Cefotaxime, Sulphamethoxazole-Trimethoprim, Penicillin G, Tetracycline, and Cephalothin, respectively. The potential hazard of MDR-, MRSA-, and VRSA-contaminated sandwiches may be an indication of the presence of what is more dangerous. Hence, strict hygienic measures and good standards of food handler's personal hygiene to prevent transmission of these pathogens to consumers are imperative.
Staphylococcus aureus is among the most common zoonotic pathogens originating from animals consumed as food, especially raw chicken meat (RCM). As far as we know, this might be the first report that explores the efficacy of metal oxide nanoparticles (MONPs), such as zinc peroxide nanoparticles (ZnO2-NPs), zinc oxide nanoparticles (ZnO-NPs), and titanium dioxide nanoparticles (TiO2-NPs) against multidrug resistant (MDR) and/or pandrug resistant (PDR) S. aureus strains with a strong biofilm-producing ability isolated from RCM and giblets. The overall prevalence of coagulase-positive staphylococci was 21%, with a contamination level range between 10² and 10⁴ CFU/g. The incidence of virulence genes See (21/36), pvl (16/36), clfA (15/36), sec (12/36), tst (12/36), and sea (11/36) among S. aureus strains were relatively higher those of seb, sed, fnbA, and fnbB. For antimicrobial resistance gene distribution, most strains harbored the blaZ gene (25/36), aacA-aphD gene (24/36), mecA gene (22/36), vanA gene (20/36), and apmA gene (20/36) confirmed the prevalence of MDR among S. aureus of RCM products. However, cfr (11/36), spc (9/36), and aadE (7/36) showed a relatively lower existence. The data of antibiogram resistance profiles was noticeably heterogeneous (25 patterns) with 32 MDR and four PDR S. aureus strains. All tested strains had a very high MAR index value (> 0.2) except the P11 pattern (GEN, MXF, PMB), which showed a MAR index of 0.19. Among the strong biofilm-producing ability (BPA), 14 (70%) strains were isolated from wet markets, while only six strong BPA strains were isolated from supermarkets. The mean values of BPA ranged from 2.613 ± 0.04 to 11.013 ± 0.05. Clearly, ZnO2-NPs show significant inhibitory activity against S. aureus strains compared with those produced by the action of ZnO-NPs and TiO2-NPs. The results of anti-inflammatory activity suggest ZnO2-NPs as a lead compound for designing an alternative antimicrobial agent against drug-resistant and strong biofilm-producing S. aureus isolates from retail RCM and giblets.
Staphylococcus aureus is among the most common zoonotic pathogens that cause foodborne illnesses worldwide. The main objectives of the current study were therefore to determine the antimicrobial susceptibility profiles of S. aureus isolated from goats in Korea and to investigate the molecular characteristics of identified methicillin-resistant S. aureus (MRSA). In the study, 481 S. aureus isolates (431 from the nasal cavity and 50 from carcass) were recovered from 1146 carcasses and nasal swabs between July 2018 and January 2019. Approximately 82% and 72.6% of nasal and carcass isolates, respectively, were resistant to at least one antimicrobial agent, with the highest rate of resistance to penicillin, followed by resistance to chloramphenicol and tetracycline. Relatively small proportions of the isolates were resistant to cefoxitin, clindamycin, and erythromycin. However, all S. aureus isolates were sensitive to linezolid, rifampin, and vancomycin. Six MRSA isolates were obtained, three each from the nasal cavity and carcass. MRSA isolates were of two sequence types (ST) (ST72 and ST398), three spa types (t664, t324, and t571), and two SCCmec types (IV and V). The ST72 MRSA isolates had identical PFGE profiles. In addition, ST72 MRSA-SCCmec IV isolates carried at least six staphylococcal leukotoxin- and enterotoxin-encoding genes (lukED, seg, sei, sem, sen, seo, and seq). The remaining ST398 isolate carried only the lukED gene and was additionally resistant to eight non–β-lactam antibiotics. To the best of our knowledge, this is the first report of MRSA from goats in Korea. There is a possibility of transmission of MRSA from goat to human or contamination of food products. Therefore, regular microbiological investigation in goats, farms, and slaughterhouses is critical to determine the existence of virulent and multi-drug resistant (MDR) S. aureus and to implement preventive strategies.
In this study, the nanocomposite film ([email protected]/ZnO) composed of sodium alginate (SA) and chitosan (CS) functionalized by copper oxide nanoparticles (CuONPs) and zinc oxide nanoparticles (ZnONPs) was fabricated, then its antibacterial mechanisms against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were systematically investigated. When the contents of CuONPs and ZnONPs reached 1.5 % (w/w) and 0.5 % (w/w), respectively, the [email protected]/ZnO exhibited great mechanical, barrier, and optical properties. Moreover, the incorporation of ZnONPs enhanced the photocatalytic ability of [email protected]/ZnO, producing a high level of reactive oxygen species under light irradiation. Further, antibacterial results showed that [email protected]/ZnO treatment inhibited the growth of E. coli and S. aureus higher than 60 % in the dark and exceeded 90 % under light irradiation. This was also manifested in the incompleteness of bacterial cell structure, accompanied by unstable cellular redox balance and DNA disruption. The functions of differentially expressed genes screened by transcriptome analysis were mainly involved in membrane transport, cell wall and membrane synthesis, cellular antioxidant defense system, cell membrane and DNA repair system. The changes in bacterial transcriptional regulation reflected the disturbance in the physiological activities and loss of cell integrity, leading to damage of bacterial cells or death.
This study evaluated the incidence of E. coli in retail chicken meat in El-Sharkia- Egypt, and the effectiveness of zinc peroxide nanoparticles (ZnO2-NPs) against pan drug-resistant bacteria (PDR) isolated from chicken meat. A total of 403 chicken meat cuts-up samples were collected. The presence of E. coli was tested by the growth on selective medium and biochemical identification followed by antibiogram assay. Various virulence factors were phenogenotypically analyzed. The data revealed a 66.3% incidence of E. coli. The incidence in the fresh cuts-up sample was significantly higher than other samples (chilled and frozen). The incidence of multidrug-resistant (MDR) strains was found to be 81%. Genotypic characterization revealed the absence of stx1 from all strains, while the stx2 gene was found in 29% of PDR isolates. Also, ZnO2-NPs showed an efficiency against all PDR E. coli strains.
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for several difficult-to-treat infections and
staphylococcal food poisoning (SFP). This study was conducted to investigate the prevalence and en-
terotoxigenicity of MRSA in broiler chicken meat and giblets. A total of 5.5% (8/144) of the examined samples
were contaminated with mecA positive/mecC negative MRSA, with staphylococcal counts of approximately 102
colony forming units (CFU)/g in breast, leg and gizzard samples and approximately 3.3 × 103 CFU/g in frozen
liver samples. Most MRSA isolates (75%, 6/8) harboured the staphylococcal enterotoxin B (seb) gene. Reverse
transcription-PCR (RT-PCR) showed that MRSA isolates initiated SEB production in experimentally con-
taminated chicken livers within 24 h of storage at temperatures over 8 °C. SEB was maximally produced at 24 °C
when the MRSA counts reached 7.3 × 103 ± 1.2 × 103 CFU/g sample homogenate. The current study con-
cludes that the main broiler chicken MRSA isolates in Egypt harbour the seb gene. To mitigate possible SEB
production, especially in broiler chicken livers, a maximum “out of refrigeration” time limit should be im-
plemented for cold chain poultry products.
Antibiotic resistance remains a significant threat to modern medicine. Modification of the antibiotic target is a resistance strategy that is increasingly prevalent among pathogens. Examples include resistance to glycopeptide and polymyxin antibiotics that occurs via chemical modification of their molecular targets in the cell envelope. Similarly, many ribosome-targeting antibiotics are impaired by methylation of the rRNA. In these cases, the antibiotic target is subjected to enzymatic modification rather than genetic mutation, and in many instances the resistance enzymes are readily mobilized among pathogens. Understanding the enzymes responsible for these modifications is crucial to combat resistance. Here, we review our current understanding of enzymatic modification of antibiotic targets as well as discuss efforts to combat these resistance mechanisms.
Implementating metal and metal oxide nanoparticles (MO-NPs) to combat bacterial resistance (due to increased findings in the mechanisms by which they act), has been the key to a better understanding and approach about the effect and kinetics that MO-NPs have on microbial strains. For this reason, it is necessary to establish guidelines and quality standards to research nano-antimicrobials, given the fact that there are many alternative methods for in vitro testing to achieve this objective, but some of them present limitations; searching for new methods could present specific results that allow us to compare them with in vivo testing. Moreover, hetero-metallic oxide nanoparticles are appearing as evolving antibacterial agents because of their improved electro-magnetic-optical characteristics. A new type of metal oxide magnetosome is evolving as suitable antibacterial as well as drug delivery materials. Further study and critical analysis of appearing literatures is required to develop these new antibacterial materials using different types of metal oxides to fight drug resistant microorganisms in the future to save the man kind.
Escherichia coli is a major global foodborne pathogen, infecting a wide range of animals and contaminating their meat products. E. coli, can lead to high morbidity and mortality with a huge economic loss especially if foodborne diseases are associated with multidrug resistant (MDR)- and multivirulent-producing pathogens. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new and innovative nanomaterials are in high demand. Recently, metal oxides can be considered as effective inorganic agents with antimicrobial features. Hence, this study might be the first to evaluate the efficiency of metal oxide nanoparticles (MO-NPs) as novel antibacterial agents against MDR/multivirulent E. coli pathogens isolated from chicken meat. The occurrence of pathogenic E. coli was determined in fresh warm chicken meat parts (breast, thigh, liver and gizzard). Ninety-one of the 132 (69%) of chicken meat parts were Escherichia -positive with E. coli as the only species isolated. Of these, 72.5% (174/240) were classified as MDR E. coli strains. Fifty-five profile patterns were obtained. From each pattern, one strain was randomly selected for further analysis of virulence and resistance genes. Extracted DNA was assessed for the presence of antibiotic resistance genes (blaIMP-7, blaIMP-25, blaTEM, blaSHV, blaOXA-2, tetA, aadA, and aac(3)-IV) and virulence genes (stx1, stx2, hlyA, eaeA, aggR, eltB, estIb, papA, afa and hlyD). Clustering analyses revealed that 10 E. coli harboring the highest number of virulence and resistance genes were shifted together into one cluster designated as cluster X. The average activities of zinc peroxide nanoparticles (ZnO2-NPs) were higher than that of zinc oxide nanoparticles (ZnO-NPs) and titanium dioxide nanoparticles (TiO2-NPs) by 20% and 29%, respectively. The anti-inflammatory activity of ZnO2-NPs in comparison with aspirin was assessed using membrane stabilization, albumin denaturation, and proteinase inhibition methods. Significant anti-inflammatory activity of ZnO2-NPs was achieved at concentration levels of 500-1000 μg/ml. It seems that MO-NPs are effective alternative agents, since they exhibited a competitive antibacterial capability against MDR/multivirulent-producing E. coli pathogens isolated from chicken meat. Hence, ZnO2-NPs are a promising nanoparticles-based material for controlling foodborne pathogens, thereby valued for food safety applications.
Water contamination by pathogenic bacteria is a global public health problem. Contamination of surface water utilized to irrigate food products, or for human consumption, causes outbreaks of foodborne and waterborne disease. Of these, those caused by diarrheagenic Escherichia coli (DEC) strains present substantial morbidity and mortality. The aim of this study was, therefore, to investigate the microbiological quality of surface water and the presence of DEC strains in different water bodies. A total of 472 water samples were collected from irrigation canal, dam, river, and dike water bodies from January through December 2015 in Sinaloa, a State located in Northwestern Mexico. Our studies demonstrated that 47.0% (222/472) of samples contained thermotolerant coliforms above permissive levels whereas E. coli strains were isolated from 43.6% (206/472). Among these E. coli isolates, DEC strains were identified in 14% (29/206) of samples including in irrigation canal (26/29) and river water (3/29) collected from the northern (83%) and central area (17%). Isolated DEC strains were classified as enteroaggregative E. coli (EAEC) 34.4% (10/29), enteropathogenic E. coli (EPEC) 31.0% (9/29), diffuse adherent E. coli (DAEC) 27.5% (8/29), and enterotoxigenic E. coli (ETEC) 6.8% (2/29). Moreover, 90% of isolated DEC strains exhibited resistance to at least one commonly prescribed antibiotic in Mexico whereas 17% were multi-drug resistant. In conclusion, the presence of DEC strains in surface water represents a potential source for human infection, and thus routine monitoring of DEC in surface water and other indirect affected areas should be considered at northwestern Mexico.
This work aimed to investigate the influence of fungal strains onto shape, functional properties, and potential applications of biosynthesized nanoparticles (NPs). The aqueous extract of two newly isolated fungal strains, Fusarium keratoplasticum strain (A1-3) and Aspergillus niger strain (G3-1), were used for synthesis of ZnO-NPs. Nanoparticles formation was confirmed by visual observation of color change and UV-visible spectroscopy. The morphological and structural properties of NPs were analyzed by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS) and zeta potential analyses. Different ZnO-NPs shapes were obtained; where, F. keratoplasticum strain (A1-3) synthesized hexagonal NPs and A. niger strain (G3-1) synthesized nano-rod shape NPs. The antibacterial activities against Gram-negative and Gram-positive bacteria as well as in vitro cytotoxicity against three different animal cell lines exhibited that the biocidal activity of NPs is a shape-dependent. Furthermore, nanoparticle shapes greatly affected the multifunctional properties of textile fabrics coated with ZnO-NPs. Nano-rod NPs showed enhanced antibacterial properties against pathogenic bacteria and UV-protection index compared to the hexagonal ZnO-NPs. Therefore, this work provides a gateway to explore e shape-dependent properties of biologically synthesized NPs and their potentiality to be utilized for specific applications.