Freshwater environments as reservoirs of antibiotic resistant bacteria and their role in the dissemination of antibiotic resistance genes. - Related Documents




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656701.0000Freshwater environments as reservoirs of antibiotic resistant bacteria and their role in the dissemination of antibiotic resistance genes. Freshwater environments are susceptible to possible contamination by residual antibiotics that are released through different sources, such as agricultural runoffs, sewage discharges and leaching from nearby farms. Freshwater environment can thus become reservoirs where an antibiotic impact microorganisms, and is an important public health concern. Degradation and dilution processes are fundamental for predicting the actual risk of antibiotic resistance dissemination from freshwater reservoirs. This study reviews major approaches for detecting and quantifying antibiotic resistance bacteria (ARBs) and genes (ARGs) in freshwater and their prevalence in these environments. Finally, the role of dilution, degradation, transmission and the persistence and fate of ARB/ARG in these environments are also reviewed. Culture-based single strain approaches and molecular techniques that include polymerase chain reaction (PCR), quantitative polymerase chain reaction (qPCR) and metagenomics are techniques for quantifying ARB and ARGs in freshwater environments. The level of ARBs is extremely high in most of the river systems (up to 98% of the total detected bacteria), followed by lakes (up to 77% of the total detected bacteria), compared to dam, pond, and spring (<1%). Of most concern is the occurrence of extended-spectrum β-lactamase producing Enterobacteriaceae, methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus (VRE), which cause highly epidemic infections. Dilution and natural degradation do not completely eradicate ARBs and ARGs in the freshwater environment. Even if the ARBs in freshwater are effectively inactivated by sunlight, their ARG-containing DNA can still be intact and capable of transferring resistance to non-resistant strains. Antibiotic resistance persists and is preserved in freshwater bodies polluted with high concentrations of antibiotics. Direct transmission of indigenous freshwater ARBs to humans as well as their transitory insertion in the microbiota can occur. These findings are disturbing especially for people that rely on freshwater resources for drinking, crop irrigation, and food in form of fish.201931465907
656810.9999Antibiotic resistance genes in water environment. The use of antibiotics may accelerate the development of antibiotic resistance genes (ARGs) and bacteria which shade health risks to humans and animals. The emerging of ARGs in the water environment is becoming an increasing worldwide concern. Hundreds of various ARGs encoding resistance to a broad range of antibiotics have been found in microorganisms distributed not only in hospital wastewaters and animal production wastewaters, but also in sewage, wastewater treatment plants, surface water, groundwater, and even in drinking water. This review summarizes recently published information on the types, distributions, and horizontal transfer of ARGs in various aquatic environments, as well as the molecular methods used to detect environmental ARGs, including specific and multiplex PCR (polymerase chain reaction), real-time PCR, DNA sequencing, and hybridization based techniques.200919130050
655720.9999Antibiotics and antibiotic resistance in water environments. Antibiotic-resistant organisms enter into water environments from human and animal sources. These bacteria are able to spread their genes into water-indigenous microbes, which also contain resistance genes. On the contrary, many antibiotics from industrial origin circulate in water environments, potentially altering microbial ecosystems. Risk assessment protocols for antibiotics and resistant bacteria in water, based on better systems for antibiotics detection and antibiotic-resistance microbial source tracking, are starting to be discussed. Methods to reduce resistant bacterial load in wastewaters, and the amount of antimicrobial agents, in most cases originated in hospitals and farms, include optimization of disinfection procedures and management of wastewater and manure. A policy for preventing mixing human-originated and animal-originated bacteria with environmental organisms seems advisable.200818534838
368330.9999Small and large-scale distribution of four classes of antibiotics in sediment: association with metals and antibiotic resistance genes. Antibiotic chemicals and antibiotic resistance genes enter the environment via wastewater effluents as well as from runoff from agricultural operations. The relative importance of these two sources, however, is largely unknown. The relationship between the concentrations of chemicals and genes requires exploration, for antibiotics in the environment may lead to development or retention of resistance genes by bacteria. The genes that confer resistance to metal toxicity may also be important in antibiotic resistance. In this work, concentrations of 19 antibiotics (using liquid chromatography tandem mass spectrometry), 14 metals (using inductively coupled plasma-mass spectrometry), and 45 metal, antibiotic, and antibiotic-resistance associated genes (using a multiplex, microfluidic quantitative polymerase chain reaction method) were measured in 13 sediment samples from two large rivers as well as along a spatial transect in a wastewater effluent-impacted lake. Nine of the antibiotics were detected in the rivers and 13 were detected in the lake. Sixteen different resistance genes were detected. The surrounding land use and proximity to wastewater treatment plants are important factors in the number and concentrations of antibiotics detected. Correlations among antibiotic chemical concentrations, metal concentrations, and resistance genes occur over short spatial scales in a lake but not over longer distances in major rivers. The observed correlations likely result from the chemicals and resistance genes arising from the same source, and differences in fate and transport over larger scales lead to loss of this relationship.201830043816
656940.9999Unveiling Rare Pathogens and Antibiotic Resistance in Tanzanian Cholera Outbreak Waters. The emergence of antibiotic resistance is a global health concern. Therefore, understanding the mechanisms of its spread is crucial for implementing evidence-based strategies to tackle resistance in the context of the One Health approach. In developing countries where sanitation systems and access to clean and safe water are still major challenges, contamination may introduce bacteria and bacteriophages harboring antibiotic resistance genes (ARGs) into the environment. This contamination can increase the risk of exposure and community transmission of ARGs and infectious pathogens. However, there is a paucity of information on the mechanisms of bacteriophage-mediated spread of ARGs and patterns through the environment. Here, we deploy Droplet Digital PCR (ddPCR) and metagenomics approaches to analyze the abundance of ARGs and bacterial pathogens disseminated through clean and wastewater systems. We detected a relatively less-studied and rare human zoonotic pathogen, Vibrio metschnikovii, known to spread through fecal--oral contamination, similarly to V. cholerae. Several antibiotic resistance genes were identified in both bacterial and bacteriophage fractions from water sources. Using metagenomics, we detected several resistance genes related to tetracyclines and beta-lactams in all the samples. Environmental samples from outlet wastewater had a high diversity of ARGs and contained high levels of blaOXA-48. Other identified resistance profiles included tetA, tetM, and blaCTX-M9. Specifically, we demonstrated that blaCTX-M1 is enriched in the bacteriophage fraction from wastewater. In general, however, the bacterial community has a significantly higher abundance of resistance genes compared to the bacteriophage population. In conclusion, the study highlights the need to implement environmental monitoring of clean and wastewater to inform the risk of infectious disease outbreaks and the spread of antibiotic resistance in the context of One Health.202337894148
372050.9999Urban wastewater as a conduit for pathogenic Gram-positive bacteria and genes encoding resistance to β-lactams and glycopeptides. The emergence and spread of clinical pathogens, antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment pose a direct threat to human and animal health worldwide. In this study, we analyzed qualitatively and quantitatively urban sewage resistome for the occurrence of genes encoding resistance to β-lactams and glycopeptides in the genomes of culturable bacteria, as well as in the wastewater metagenome of the Central Wastewater Treatment Plant in Koziegłowy (Poland). Moreover, we estimated the presence of pathogenic Gram-positive bacteria in wastewater based on analysis of species-specific virulence genes in the wastewater metagenome. The results show that the final effluent contains alarm pathogens with particularly dangerous mechanisms of antibiotic resistance, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). We also noticed that during the wastewater treatment, there is an increase in the frequency of MRSA and VRE. Furthermore, the results prove the effective removal of vanA, but at the same time show that wastewater treatment increases the relative abundance of mecA and virulence genes (groES and sec), indicating the presence of clinical pathogens E. faecalis and S. aureus in the effluent released to surface waters. We also observed an increase in the relative abundance of mecA and vanA genes already in the aeration tank, which suggests accumulation of contaminants affecting enhanced selection and HGT processes in the activated sludge. Moreover, we found a relation between the taxonomic composition and the copy number of ARGs as well as the presence of pathogens at various stages of wastewater treatment. The presence of clinically relevant pathogens, ARB, including multi-resistant bacteria, and ARGs in the effluent indicates that wastewater treatment plant play a key role in the existence of pathogens and antimicrobial resistance spreading pathway in the environment and human communities, which is a direct threat to public health and environmental protection.202133385807
736460.9999Anthropogenic influence shapes the distribution of antibiotic resistant bacteria (ARB) in the sediment of Sundarban estuary in India. The abundance and dissemination of antibiotic resistance genes as emerging environmental contaminants have become a significant and growing threat to human and environmental health. Traditionally, investigations of antibiotic resistance have been confined to a subset of clinically relevant antibiotic-resistant bacterial pathogens. During the last decade it became evident that the environmental microbiota possesses an enormous number and diversity of antibiotic resistance genes, some of which are very similar to the genes circulating in pathogenic microbiota. Recent studies demonstrate that aquatic ecosystems are potential reservoirs of antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs). Therefore, these aquatic ecosystems serve as potential sources for their transmission of ARGs to human pathogens. An assessment of such risks requires a better understanding of the level and variability of the natural resistance background and the extent of the anthropogenic impact. We have analyzed eight sediment samples from Sundarban mangrove ecosystem in India, collected at sampling stations with different histories of anthropogenic influences, and analyzed the relative abundance of the bla(TEM) gene using quantitative real-time PCR. The bla(TEM) gene abundance strongly correlated with the respective anthropogenic influences (polyaromatic hydrocarbon, heavy metals etc.) of the sampling stations. Besides, 18 multidrug-resistant (ampicillin, kanamycin, vancomycin, and tetracycline resistant) bacterial strains (ARBs) were isolated and characterized. Moreover, the effect of different antibiotics on the biofilm forming ability of the isolates was evaluated quantitatively under a variety of experimental regimes. This is the first report of preservation and possible dissemination of ARGs in the mangrove ecosystem.201930180366
388670.9999β-Lactam antibiotics and antibiotic resistance in Asian lakes and rivers: An overview of contamination, sources and detection methods. Lakes and rivers are sources of livelihood, food and water in many parts of the world. Lakes provide natural resources and valuable ecosystem services. These aquatic ecosystems are also vulnerable to known and new environmental pollutants. Emerging water contaminants are now being studied including antibiotics because of the global phenomenon on antibiotic resistance. β-Lactam antibiotics are widely used in human and animal disease prevention or treatment. The emergence of antibiotic resistance is a public health threat when bacteria become more resistant and infections consequently increase requiring treatment using last resort drugs that are more expensive. This review summarizes the key findings on the occurrence, contamination sources, and determination of β-lactam antibiotics and β-lactam antibiotic resistant bacteria and genes in the Asian lake and river waters. The current methods in the analytical measurements of β-lactam antibiotics in water involving solid-phase extraction and liquid chromatography-mass spectrometry are discussed. Also described is the determination of antibiotic resistance genes which is primarily based on a polymerase chain reaction method. To date, β-lactam antibiotics in the Asian aquatic environments are reported in the ng/L concentrations. Studies on β-lactam resistant bacteria and resistance genes were mostly conducted in China. The occurrence of these emerging contaminants is largely uncharted because many aquatic systems in the Asian region remain to be studied. Comprehensive investigations encompassing the environmental behavior of β-lactam antibiotics, emergence of resistant bacteria, transfer of resistance genes to non-resistant bacteria, multiple antibiotic resistance, and effects on aquatic biota are needed particularly in rivers and lakes that are eventual sinks of these water contaminants.202133571856
371980.9999Vancomycin-Resistant Enterococci and Bacterial Community Structure following a Sewage Spill into an Aquatic Environment. Sewage spills can release antibiotic-resistant bacteria into surface waters, contributing to environmental reservoirs and potentially impacting human health. Vancomycin-resistant enterococci (VRE) are nosocomial pathogens that have been detected in environmental habitats, including soil, water, and beach sands, as well as wildlife feces. However, VRE harboring vanA genes that confer high-level resistance have infrequently been found outside clinical settings in the United States. This study found culturable Enterococcus faecium harboring the vanA gene in water and sediment for up to 3 days after a sewage spill, and the quantitative PCR (qPCR) signal for vanA persisted for an additional week. Culturable levels of enterococci in water exceeded recreational water guidelines for 2 weeks following the spill, declining about five orders of magnitude in sediments and two orders of magnitude in the water column over 6 weeks. Analysis of bacterial taxa via 16S rRNA gene sequencing showed changes in community structure through time following the sewage spill in sediment and water. The spread of opportunistic pathogens harboring high-level vancomycin resistance genes beyond hospitals and into the broader community and associated habitats is a potential threat to public health, requiring further studies that examine the persistence, occurrence, and survival of VRE in different environmental matrices. IMPORTANCE: Vancomycin-resistant enterococci (VRE) are harmful bacteria that are resistant to the powerful antibiotic vancomycin, which is used as a last resort against many infections. This study followed the release of VRE in a major sewage spill and their persistence over time. Such events can act as a means of spreading vancomycin-resistant bacteria in the environment, which can eventually impact human health.201627422829
656690.9999Antimicrobial resistance bacteria and genes detected in hospital sewage provide valuable information in predicting clinical antimicrobial resistance. Extensive use of antibiotics is significantly associated with development of antibiotic-resistant (AR) bacteria. However, their causal relationships have not been adequately investigated, especially in human population and hospitals. Our aims were to understand clinical AR through revealing co-occurrence patterns between antibiotic-resistant bacteria and genes (ARB and ARGs), and their association with antibiotic use, and to consider impact of ARB and ARGs on environmental and human health. Antibiotic usage was calculated based on the actual consumption in our target hospital. ARB was identified by culture. In isolates collected from hospital sewage, bacterial-specific DNA sequences and ARGs were determined using metagenomics. Our data revealed that the use of culture-based single-indicator-strain approaches only captured ARB in 16.17% of the infectious samples. On the other hand, 1573 bacterial species and 885 types of ARGs were detected in the sewage. Furthermore, hospital use of antibiotics influenced the resistance profiles, but the strength varied among bacteria. From our metagenomics analyses, ARGs for aminoglycosides were the most common, followed by sulfonamide, tetracycline, phenicol, macrolides, and quinolones, comprising 82.6% of all ARGs. Association analyses indicated that 519 pairs of ARGs were significantly correlated with ARB species (r > 0.8). The co-occurrence patterns of bacteria-ARGs mirrored the AR in the clinic. In conclusion, our systematic investigation further emphasized that antibiotic usage in hospital significantly influenced the abundance and types of ARB and ARGs in dose- and time-dependent manners which, in turn, mirrored clinical AR. In addition, our data provide novel information on development of certain ARB with multiple antibiotic resistance. These ARB and ARGs from sewage can also be disseminated into the environment and communities to create health problems. Therefore, it would be helpful to use such data to develop improved predictive risk model of AR, to enhance effective use of antibiotics, and to reduce environmental pollution.202134247085
6565100.9999Modeling the impact of urban and hospital eco-exposomes on antibiotic-resistance dynamics in wastewaters. The emergence and selection of antibiotic resistance is a major public health problem worldwide. The presence of antibiotic-resistant bacteria (ARBs) in natural and anthropogenic environments threatens the sustainability of efforts to reduce resistance in human and animal populations. Here, we use mathematical modeling of the selective effect of antibiotics and contaminants on the dynamics of bacterial resistance in water to analyze longitudinal spatio-temporal data collected in hospital and urban wastewater between 2012 and 2015. Samples were collected monthly during the study period at four different sites in Haute-Savoie, France: hospital and urban wastewater, before and after water treatment plants. Three different categories of exposure variables were collected simultaneously: 1) heavy metals, 2) antibiotics and 3) surfactants for a total of 13 drugs/molecules; in parallel to the normalized abundance of 88 individual genes and mobile genetic elements, mostly conferring resistance to antibiotics. A simple hypothesis-driven model describing weekly antibiotic resistance gene (ARG) dynamics was proposed to fit the available data, assuming that normalized gene abundance is proportional to antibiotic resistant bacteria (ARB) populations in water. The detected compounds were found to influence the dynamics of 17 genes found at multiple sites. While mercury and vancomycin were associated with increased ARG and affected the dynamics of 10 and 12 identified genes respectively, surfactants antagonistically affected the dynamics of three genes. The models proposed here make it possible to analyze the relationship between the persistence of resistance genes in the aquatic environment and specific compounds associated with human activities from longitudinal data. Our analysis of French data over 2012-2015 identified mercury and vancomycin as co-selectors for some ARGs.202438471588
6573110.9999The bacterial biofilm resistome in drinking water distribution systems: A systematic review. Antibiotic resistance in drinking water systems poses human health risks. Earlier studies, including reviews on antibiotic resistance in drinking water systems are limited to the occurrence, behaviour and fate in bulk raw water and drinking water treatment systems. By comparison, reviews on the bacterial biofilm resistome in drinking water distribution systems are still limited. Therefore, the present systematic review investigates the occurrence, behaviour and fate and, detection methods of bacterial biofilm resistome in the drinking water distribution systems. A total of 12 original articles drawn from 10 countries were retrieved and analyzed. Antibiotic resistant bacteria and antibiotic resistance genes detected in biofilms include those for sulfonamides, tetracycline, and beta-lactamase. The genera detected in biofilms include Staphylococcus, Enterococcus, Pseudomonas, Ralstonia, Mycobacteria, as well as Enterobacteriaceae family and other gram-negative bacteria. The presence of Enterococcus faecium, Staphylococcusaureus, Klebsiella pneumoniae, Acinetobacterbaumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE bacteria) among the detected bacteria points to potential human exposure and health risks especially for susceptible individuals via the consumption of drinking water. Besides, the effects of water quality parameter and residual chlorine, the physico-chemical factors controlling the emergence, persistence and fate of the biofilm resistome are still poorly understood. Culture-based methods, and molecular methods, and their advantages and limitations are discussed. The limited data on the bacterial biofilm resistome in drinking water distribution system points to the need for further research. To this end, future research directions are discussed including understanding the formation, behaviour, and fate of the resistome and the controlling factors.202337059195
3454120.9999Antibiotic Resistance Genes in Phage Particles from Antarctic and Mediterranean Seawater Ecosystems. Anthropogenic activities are a key factor in the development of antibiotic resistance in bacteria, a growing problem worldwide. Nevertheless, antibiotics and resistances were being generated by bacterial communities long before their discovery by humankind, and might occur in areas without human influence. Bacteriophages are known to play a relevant role in the dissemination of antibiotic resistance genes (ARGs) in aquatic environments. In this study, five ARGs (bla(TEM), bla(CTX-M-1), bla(CTX-M-9), sul1 and tetW) were monitored in phage particles isolated from seawater of two different locations: (i) the Mediterranean coast, subjected to high anthropogenic pressure, and (ii) the Antarctic coast, where the anthropogenic impact is low. Although found in lower quantities, ARG-containing phage particles were more prevalent among the Antarctic than the Mediterranean seawater samples and Antarctic bacterial communities were confirmed as their source. In the Mediterranean area, ARG-containing phages from anthropogenic fecal pollution might allow ARG transmission through the food chain. ARGs were detected in phage particles isolated from fish (Mediterranean, Atlantic, farmed, and frozen), the most abundant being β-lactamases. Some of these particles were infectious in cultures of the fecal bacteria Escherichia coli. By serving as ARG reservoirs in marine environments, including those with low human activity, such as the Antarctic, phages could contribute to ARG transmission between bacterial communities.202032847015
6570130.9999Impact of point sources on antibiotic resistance genes in the natural environment: a systematic review of the evidence. There is a growing concern about the role of the environment in the dissemination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG). In this systematic review, we summarize evidence for increases of ARG in the natural environment associated with potential sources of ARB and ARG such as agricultural facilities and wastewater treatment plants. A total of 5247 citations were identified, including studies that ascertained both ARG and ARB outcomes. All studies were screened for relevance to the question and methodology. This paper summarizes the evidence only for those studies with ARG outcomes (n = 24). Sixteen studies were at high (n = 3) or at unclear (n = 13) risk of bias in the estimation of source effects due to lack of information or failure to control for confounders. Statistical methods were used in nine studies; three studies assessed the effect of multiple sources using modeling approaches, and none reported effect measures. Most studies reported higher ARG concentration downstream/near the source, but heterogeneous findings hindered making any sound conclusions. To quantify increases of ARG in the environment due to specific point sources, there is a need for studies that emphasize analytic or design control of confounding, and that provide effect measure estimates.201729231804
3980140.9999Antimicrobial resistance in dairy slurry tanks: A critical point for measurement and control. Waste from dairy production is one of the largest sources of contamination from antimicrobial resistant bacteria (ARB) and genes (ARGs) in many parts of the world. However, studies to date do not provide necessary evidence to inform antimicrobial resistance (AMR) countermeasures. We undertook a detailed, interdisciplinary, longitudinal analysis of dairy slurry waste. The slurry contained a population of ARB and ARGs, with resistances to current, historical and never-used on-farm antibiotics; resistances were associated with Gram-negative and Gram-positive bacteria and mobile elements (ISEcp1, Tn916, Tn21-family transposons). Modelling and experimental work suggested that these populations are in dynamic equilibrium, with microbial death balanced by fresh input. Consequently, storing slurry without further waste input for at least 60 days was predicted to reduce ARB spread onto land, with > 99 % reduction in cephalosporin resistant Escherichia coli. The model also indicated that for farms with low antibiotic use, further reductions are unlikely to reduce AMR further. We conclude that the slurry tank is a critical point for measurement and control of AMR, and that actions to limit the spread of AMR from dairy waste should combine responsible antibiotic use, including low total quantity, avoidance of human critical antibiotics, and choosing antibiotics with shorter half-lives, coupled with appropriate slurry storage.202236122459
3682150.9999Concentration of facultative pathogenic bacteria and antibiotic resistance genes during sewage treatment and in receiving rivers. Whereas the hygienic condition of drinking and bathing water by law must be monitored by culture-based methods, for quantification of microbes and antibiotic resistance in soil or the aquatic environment, often molecular genetic assays are used. For comparison of both methods, knowledge of their correlation is necessary. Therefore the population of total bacteria, Escherichia coli, enterococci and staphylococci during sewage treatment and in receiving river water was compared by agar plating and quantitative polymerase chain reaction (qPCR) assays. In parallel, all samples were investigated for clinically relevant antibiotic resistance genes. Whereas plating and qPCR data for total bacteria correlated well in sewage after primary treatment, qPCR data of river water indicated higher cell numbers for E. coli. It is unknown if these cells are 'only' not growing under standard conditions or if they are dead. Corresponding to the amount of non-culturable cells, the 'breakpoints' for monitoring water quality should be adapted. The abundances of clinically relevant antibiotic resistance genes in river water were in the same order of magnitude or even higher than in treated sewage. For estimation of the health risk it is important to investigate which species carry respective genes and whether these genes are disseminated via gene transfer.201627789876
7397160.9999Persistence of naturally occurring antibiotic resistance genes in the bacteria and bacteriophage fractions of wastewater. The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs from bacteria can be mobilized by mobile genetic elements, and recent studies indicate that phages and phage-derived particles, among others, could play a role in the spread of ARGs through the environment. ARGs are abundant in the bacterial and bacteriophage fractions of water bodies and for successful transfer of the ARGs, their persistence in these environments is crucial. In this study, three ARGs (blaTEM, blaCTX-M and sul1) that naturally occur in the bacterial and phage fractions of raw wastewater were used to evaluate the persistence of ARGs at different temperatures (4 °C, 22 °C and 37 °C) and pH values (3, 7 and 9), as well as after various disinfection treatments (thermal treatment, chlorination and UV) and natural inactivation in a mesocosm. Gene copies (GC) were quantified by qPCR; then the logarithmic reduction and significance of the differences between their numbers were evaluated. The ARGs persisted for a long time with minimal reductions after all the treatments. In general, they showed greater persistence in the bacteriophage fraction than in the bacterial fraction. Comparisons showed that the ARGs persisted under conditions that reduced culturable Escherichia coli and infectious coliphages below the limit of detection. The prevalence of ARGs, particularly in the bacteriophage fraction, poses the threat of the spread of ARGs and their incorporation into a new bacterial background that could lead to the emergence of new resistant clones.201626978717
3287170.9999Antimicrobial resistance screening and profiles: a glimpse from the South African perspective. According to the Centre for Disease Dynamics Economics and Policy, South Africa represents a paradox of antibiotic management similar to other developing countries, with both overuse and underuse (resulting from lack of access) of antibiotics. In addition, wastewater reuse may contribute towards antibiotic resistance through selective pressure that increases resistance in native bacteria and on clinically relevant bacteria, increasing resistance profiles of the common pathogens. Sediments of surface water bodies and wastewater sludge provide a place where antibiotic resistance genes are transferred to other bacteria. Crop irrigation is thought to be a potential source of exposure to antibiotic-resistant bacteria through the transfer from the water or sludge into crops. The objectives of this study were to examine the antibiotic-resistance profiles of Escherishia coli from three agricultural locations in the Western Cape, South Africa. Using a classical microbiology culture approach, the resistance profiles of E. coli species isolated from river water and sediments, farm dams and their sediments and a passive algal wastewater treatment ponds and sediment used for crop irrigation were assessed for resistance to 13 commonly used antibiotics. Randomly selected E. coli isolates from the sediment and water were tested for resistance. 100% of E. coli isolates were resistant to sulphamethoxazole, highlighting its relevance in the South African context. In river water and farm dam samples, only the E. coli isolated from sediment were found to be resistant to fluoroquinolone or fluorifenicol. In the wastewater treatment ponds, the resistance profiles of E. coli isolated from sediments differed from those isolated from effluent, with 90% of the effluent isolates being resistant to ampicillin. Isolates from the sediment were less resistant (40%) to ampicillin, whereas all the isolates from the pond water and sediment samples were resistant to sulphamethoxazole. These results illustrate the importance of developing a better understanding of antibiotic resistance in agriculture and wastewater scenarios to ensure remedial measures take place where the greatest benefit can be realised especially in countries with limited financial and infrastructural resources. Moreover, the potential for passive algal treatment as an effective, feasible alternative for wastewater treatment is highlighted, with comparable resistance profiles and a reducing overall resistance in the sediment samples.202033328364
7393180.9999Fate and distribution of determinants of antimicrobial resistance in lateral flow sand filters used for treatment of domestic wastewater. Residuals of antimicrobial products from anthropogenic uses can create a selective environment in domestic wastewater treatment systems and receiving environments and contribute to the spread of antimicrobial resistance (AMR). On-site wastewater treatment systems are widely used for domestic wastewater management in rural and remote regions, but the fate of determinants of AMR in these types of environments has received little attention. In this study, the mechanisms responsible for the attenuation of determinants of AMR in lateral flow sand filters were explored using a combination of lab, field and modeling investigations. The degradation kinetics and adsorption potential in the sand filter medium of three antibiotic resistance genes (ARGs; sul1, tetO, and ermB) and culturable bacteria resistant to sulfamethoxazole, tetracycline, and erythromycin were measured using lab experiments. The spatial distribution of ARGs and antibiotic resistant bacteria were also assessed in field scale sand filters, and mechanistic modeling was conducted to characterize filtration processes. The results indicated that the primary mechanisms responsible for AMR attenuation within the sand filters were degradation and filtration. The spatial distribution of AMR determinants illustrated that attenuation was occurring along the entire length of each filter. This study provides new insights on primary mechanisms of AMR attenuation in on-site wastewater treatment systems and supports the use of conservative design guidelines and separation distances for reducing AMR transmission.202133636762
3462190.9998Environmental health of water bodies from a Brazilian Amazon Metropolis based on a conventional and metagenomic approach. AIMS: The present study aimed to use a conventional and metagenomic approach to investigate the microbiological diversity of water bodies in a network of drainage channels and rivers located in the central area of the city of Belém, northern Brazil, which is considered one of the largest cities in the Brazilian Amazon. METHODS AND RESULTS: In eight of the analyzed points, both bacterial and viral microbiological indicators of environmental contamination-physical-chemical and metals-were assessed. The bacterial resistance genes, drug resistance mechanisms, and viral viability in the environment were also assessed. A total of 473 families of bacteria and 83 families of viruses were identified. Based on the analysis of metals, the levels of three metals (Cd, Fe, and Mn) were found to be above the recommended acceptable level by local legislation. The levels of the following three physicochemical parameters were also higher than recommended: biochemical oxygen demand, dissolved oxygen, and turbidity. Sixty-three bacterial resistance genes that conferred resistance to 13 different classes of antimicrobials were identified. Further, five mechanisms of antimicrobial resistance were identified and viral viability in the environment was confirmed. CONCLUSIONS: Intense human actions combined with a lack of public policies and poor environmental education of the population cause environmental degradation, especially in water bodies. Thus, urgent interventions are warranted to restore the quality of this precious and scarce asset worldwide.202438627246