Prevalence of antibiotic resistance in drinking water treatment and distribution systems. - Related Documents




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730701.0000Prevalence of antibiotic resistance in drinking water treatment and distribution systems. The occurrence and spread of antibiotic-resistant bacteria (ARB) are pressing public health problems worldwide, and aquatic ecosystems are a recognized reservoir for ARB. We used culture-dependent methods and quantitative molecular techniques to detect and quantify ARB and antibiotic resistance genes (ARGs) in source waters, drinking water treatment plants, and tap water from several cities in Michigan and Ohio. We found ARGs and heterotrophic ARB in all finished water and tap water tested, although the amounts were small. The quantities of most ARGs were greater in tap water than in finished water and source water. In general, the levels of bacteria were higher in source water than in tap water, and the levels of ARB were higher in tap water than in finished water, indicating that there was regrowth of bacteria in drinking water distribution systems. Elevated resistance to some antibiotics was observed during water treatment and in tap water. Water treatment might increase the antibiotic resistance of surviving bacteria, and water distribution systems may serve as an important reservoir for the spread of antibiotic resistance to opportunistic pathogens.200919581476
319710.9999Antibiotic resistance and pathogen spreading in a wastewater treatment plant designed for wastewater reuse. Climate change significantly contributes to water scarcity in various regions worldwide. While wastewater reuse is a crucial strategy for mitigating water scarcity, it also carries potential risks for human health due to the presence of pathogenic and antibiotic resistant bacteria (ARB). Antibiotic resistance represents a Public Health concern and, according to the global action plan on antimicrobial resistance, wastewater role in selecting and spreading ARB must be monitored. Our aim was to assess the occurrence of ARB, antibiotic resistance genes (ARGs), and potential pathogenic bacteria throughout a wastewater treatment plant (WWTP) designed for water reuse. Furthermore, we aimed to evaluate potential association between ARB and ARGs with antibiotics and heavy metals. The results obtained revealed the presence of ARB, ARGs and pathogenic bacteria at every stage of the WWTP. Notably, the most prevalent ARB and ARG were sulfamethoxazole-resistant bacteria (up to 7.20 log CFU mL(-1)) and sulII gene (up to 5.91 log gene copies mL(-1)), respectively. The dominant pathogenic bacteria included Arcobacter, Flavobacterium and Aeromonas. Although the abundance of these elements significantly decreased during treatment (influent vs. effluent, p < 0.05), they were still present in the effluent designated for reuse. Additionally, significant correlations were observed between heavy metal concentrations (copper, nickel and selenium) and antibiotic resistance elements (ampicillin-resistant bacteria, tetracycline-resistant bacteria, ARB total abundance and sulII) (p < 0.05). These results underscore the importance of monitoring the role of WWTP in spreading antibiotic resistance, in line with the One Health approach. Additionally, our findings suggest the need of interventions to reduce human health risks associated with the reuse of wastewater for agricultural purposes.202439357555
730920.9999Identification of Selected Antibiotic Resistance Genes in Two Different Wastewater Treatment Plant Systems in Poland: A Preliminary Study. Antibiotic resistance is a growing problem worldwide. The emergence and rapid spread of antibiotic resistance determinants have led to an increasing concern about the potential environmental and public health endangering. Wastewater treatment plants (WWTPs) play an important role in this phenomenon since antibacterial drugs introduced into wastewater can exert a selection pressure on antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Therefore, WWTPs are perceived as the main sources of antibiotics, ARB and ARG spread in various environmental components. Furthermore, technological processes used in WWTPs and its exploitation conditions may influence the effectiveness of antibiotic resistance determinants' elimination. The main aim of the present study was to compare the occurrence of selected tetracycline and sulfonamide resistance genes in raw influent and final effluent samples from two WWTPs different in terms of size and applied biological wastewater treatment processes (conventional activated sludge (AS)-based and combining a conventional AS-based method with constructed wetlands (CWs)). All 13 selected ARGs were detected in raw influent and final effluent samples from both WWTPs. Significant ARG enrichment, especially for tet(B, K, L, O) and sulIII genes, was observed in conventional WWTP. The obtained data did not show a clear trend in seasonal fluctuations in the abundance of selected resistance genes in wastewaters.202032575673
728430.9999Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes. Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.201525913323
731540.9999Seasonal variability of the correlation network of antibiotics, antibiotic resistance determinants, and bacteria in a wastewater treatment plant and receiving water. Sewage treatment plants are an essential source of antibiotics, antibiotic resistance determinants, and bacteria in environmental waters. However, it is still unclear whether they can maintain a relatively stable relationship in wastewater and environmental waters. This study analyzed the removal capacity of the above three pollutants in the sewage treatment plant in summer and their impact on environmental waters, and then examines the relationship between the three contaminants in the wastewater and environmental waters in summer and winter based on our previous study. The results found that the removal capacity of bacteria in summer was poor, the concentration of fluoroquinolone in the effluent was higher than that in influent, and the abundance of intI1, tetW, qnrB, and ermB increased after wastewater treatment. Proteobacteria and Bacteroides were the main bacteria that constitute the correlation network between bacteria, and they existed stably in summer and winter. However, fluoroquinolones occupied a significant position in the determinant network of antibiotics and antibiotic resistance in summer and winter. There are fewer correlation between antibiotics and antibiotics resistance determinants in winter. Interestingly, the relationship between bacteria, antibiotics, and antibiotic resistance determinants was a mainly positive correlation in summer and negative correlation in winter. This study analyzed the relationship between bacteria, antibiotics, and antibiotic resistance determinants that were stable in the wastewater and environmental waters and pointed out the direction for subsequent targeted seasonal control of novel pollutants in wastewater and environmental waters.202235642820
730850.9999Urban wastewater effluent increases antibiotic resistance gene concentrations in a receiving northern European river. Antibiotic-resistant bacteria are an emerging global problem that threatens to undermine important advances in modern medicine. The environment is likely to play an important role in the dissemination of antibiotic-resistance genes (ARGs) among both environmental and pathogenic bacteria. Wastewater treatment plants (WWTPs) accumulate both chemical and biological waste from the surrounding urban milieu and have therefore been viewed as potential hotspots for dissemination and development of antibiotic resistance. To assess the effect of wastewater effluent on a river that flows through a Swedish city, sediment and water samples were collected from Stångån River, both upstream and downstream of an adjacent WWTP over 3 mo. Seven ARGs and the integrase gene on class 1 integrons were quantified in the collected sediment using real-time polymerase chain reaction (PCR). Liquid chromatography-mass spectrometry was used to assess the abundance of 10 different antibiotics in the water phase of the samples. The results showed an increase in ARGs and integrons downstream of the WWTP. The measured concentrations of antibiotics were low in the water samples from the Stångån River, suggesting that selection for ARGs did not occur in the surface water. Instead, the downstream increase in ARGs is likely to be attributable to accumulation of genes present in the treated effluent discharged from the WWTP.201525331227
722960.9999Occurrence of antibiotic-resistant bacteria and resistance genes in the urban water cycle. This study investigates the antibiotic resistance fate in the urban water cycle, evaluating the dynamics of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in three different full-scale wastewater treatment plants (WWTPs) and two drinking water treatment plants (DWTPs) located in the same geographical area (North-West of Italy). ARB (tetracycline-, ampicillin-, and sulfonamide-resistant bacteria) were quantified by plate counting and the abundances of selected ARGs (i.e., tetA, bla(TEM), and sulII) and intI1 gene were measured using quantitative real-time PCR (qPCR). Higher concentrations of ARB and ARGs were observed in the WWTPs with respect to the DWTPs identifying the WWTP as hotspot for the spread of antibiotic resistances. Although a significant reduction of ARB and ARGs was observed in WWTPs and DWTPs after the treatment, none of the detected ARB or ARGs was completely removed in drinking water. The stability of the antibiotic-resistant rates between inlet and outlet associated with the reduction of relative ARG abundances underlined that both the treatments (WWTs and DWTs) did not apply any selective pressure. The overall results highlighted the importance to investigate the antibiotic resistance dynamics in aquatic ecosystems involved in urban water cycle integrating the information obtained by culture-dependent method with the culture-independent one and the need to monitor the presence of ARB and ARGs mainly in drinking water that represents a potential route of transmission to human.202336527555
722770.9999High-risk antibiotics positively correlated with antibiotic resistance genes in five typical urban wastewater. Antibiotic resistance genes (ARGs) and antibiotic amount increased within close proximity to human dominated ecosystems. However, few studies assessed the distribution of antibiotics and ARGs in multiple ecosystems especially the different urban wastewater. In this study, the spatial distribution of ARGs and antibiotics across the urban wastewater included domestic, livestock, hospital, pharmaceutical wastewater, influent of the wastewater treatment plant (WWTP) in Northeast China. The q-PCR results showed that ARGs were most abundant in community wastewater and followed by WWTP influent, livestock wastewater, pharmaceutical wastewater and hospital wastewater. The ARG composition differed among the five ecotypes with qnrS was the dominant ARG subtypes in WWTP influent and community wastewater, while sul2 dominant in livestock, hospital, pharmaceutical wastewater. The concentration of antibiotics was closely related to the antibiotic usage and consumption data. In addition to the high concentration of azithromycin at all sampling points, more than half of the antibiotics in livestock wastewater were veterinary antibiotics. However, antibiotics that closely related to humankind such as roxithromycin and sulfamethoxazole accounted for a higher proportion in hospital wastewater (13.6%) and domestic sewage (33.6%), respectively. The ambiguous correlation between ARGs and their corresponding antibiotics was detected. However, antibiotics that exhibited high ecotoxic effects were closely and positively correlated with ARGs and the class 1 integrons (intI1), which indicated that high ecotoxic compounds might affect antimicrobial resistance of bacteria by mediating horizontal gene transfer of ARGs. The coupling mechanism between the ecological risk of antibiotics and bacterial resistance needed to be further studied, and thereby provided a new insight to study the impact of environmental pollutants on ARGs in various ecotypes.202337267763
731480.9999Microbial diversity and antibiotic resistance in a final effluent-receiving lake. Wastewater treatment plants have been recognised as hotspots for antibiotic resistance genes and antibiotic-resistant bacteria which enter the environment. However, the persistence of these genes and bacteria in receiving ecosystems remains poorly understood. The aim of the study was to evaluate the effect of final effluent release on microbial diversity and the antibiotic resistance gene pool in a final effluent-receiving lake. The numbers of total culturable heterotrophs and unculturable bacteria (represented as the 16S rRNA gene copy number) were significantly reduced during the treatment process. The number of ampicillin-resistant bacteria was higher in the sediment than in water samples, suggesting accumulation of ampicillin-resistant bacteria in freshwater sediments. Using an exogenous method, we captured 56 resistance plasmids which were further characterised. Next-generation sequencing revealed that the microbial phyla represented in the studied metagenomes were typical of corresponding environments. The highest relative abundance of antibiotic resistance genes was observed in the final effluent, suggesting that a considerable number of genes were released from the wastewater treatment plant. However, the lowest relative abundance and lowest diversity of the genes in the lake water, compared to the other studied metagenomes, suggest a negligible effect of treated sewage release on antibiotic resistance within water microbial communities of the lake. Furthermore, uncontrolled sewage dumping into this reservoir in the past as well as lower quality of the water upstream of the lake indicated that the wastewater treatment plant protected the studied ecosystem.201930373071
728390.9999Comparative metagenomics reveals a diverse range of antimicrobial resistance genes in effluents entering a river catchment. The aquatic environment has been implicated as a reservoir for antimicrobial resistance genes (ARGs). In order to identify sources that are contributing to these gene reservoirs, it is crucial to assess effluents that are entering the aquatic environment. Here we describe a metagenomic assessment for two types of effluent entering a river catchment. We investigated the diversity and abundance of resistance genes, mobile genetic elements (MGEs) and pathogenic bacteria. Findings were normalised to a background sample of river source water. Our results show that effluent contributed an array of genes to the river catchment, the most abundant being tetracycline resistance genes tetC and tetW from farm effluents and the sulfonamide resistance gene sul2 from wastewater treatment plant (WWTP) effluents. In nine separate samples taken across 3 years, we found 53 different genes conferring resistance to seven classes of antimicrobial. Compared to the background sample taken up river from effluent entry, the average abundance of genes was three times greater in the farm effluent and two times greater in the WWTP effluent. We conclude that effluents disperse ARGs, MGEs and pathogenic bacteria within a river catchment, thereby contributing to environmental reservoirs of ARGs.201627054725
7291100.9999Accumulation of clinically relevant antibiotic-resistance genes, bacterial load, and metals in freshwater lake sediments in Central Europe. Wastewater treatment plants (WWTP) receive the effluents from various sources (communities, industrial, and hospital effluents) and are recognized as reservoir for antibiotic-resistance genes (ARGs) that are associated with clinical pathogens. The aquatic environment is considered a hot-spot for horizontal gene transfer, and lake sediments offer the opportunity for reconstructing the pollution history and evaluating the impacts. In this context, variation with depth and time of the total bacterial load, the abundance of faecal indicator bacteria (FIB; E. coli and Enterococcus spp. (ENT)), Pseudomonas spp., and ARGs (blaTEM, blaSHV, blaCTX-M, blaNDM, and aadA) were quantified in sediment profiles of different parts of Lake Geneva using quantitative PCR. The abundance of bacterial marker genes was identified in sediments contaminated by WWTP following eutrophication of the lake. Additionally, ARGs, including the extended-spectrum ß-lactam- and aminoglycoside-resistance genes, were identified in the surface sediments. The ARG and FIB abundance strongly correlated (r ≥ 0.403, p < 0.05, n = 34) with organic matter and metal concentrations in the sediments, indicating a common and contemporary source of contamination. The contamination of sediments by untreated or partially treated effluent water can affect the quality of ecosystem. Therefore, the reduction of contaminants from the source is recommended for further improvement of water quality.201525933054
7293110.9999Prevalence and transmission of antibiotic resistance and microbiota between humans and water environments. The transmission routes for antibiotic resistance genes (ARGs) and microbiota between humans and water environments is poorly characterized. Here, we used high-throughput qPCR analyses and 16S rRNA gene sequencing to examine the occurrence and abundance of antibiotic resistance genes and microbiota in both healthy humans and associated water environments from a Chinese village. Humans carried the most diverse assemblage of ARGs, with 234 different ARGs being detected. The total abundance of ARGs in feces, on skin, and in the effluent from domestic sewage treatment systems were approximately 23, 2, and 7 times higher than their abundance in river samples. In total, 53 ARGs and 28 bacteria genera that were present in human feces could also be found in the influent and effluent of rural sewage treatment systems, and also downstream of the effluent release point. We identified the bacterial taxa that showed a significant association with ARGs (P < 0.01, r > 0.8) by network analysis, supporting the idea that these bacteria could carry some ARGs and transfer between humans and the environment. Analysis of ARGs and microbiota in humans and in water environments helps to define the transmission routes and dynamics of antibiotic resistance within these environments. This study highlights human contribution to the load of ARGs into the environment and suggests means to prevent such dissemination.201830420129
6565120.9999Modeling 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
7310130.9999Metagenomic Analysis Reveals Changes in Bacterial Communities and Antibiotic Resistance Genes in an Eye Specialty Hospital and a General Hospital Before and After Wastewater Treatment. The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in hospital wastewater poses a great threat to public health, and wastewater treatment plants (WWTPs) play an important role in reducing the levels of ARB and ARGs. In this study, high-throughput metagenomic sequencing was used to analyze the bacterial community composition and ARGs in two hospitals exposed to different antibiotic use conditions (an eye specialty hospital and a general hospital) before and after wastewater treatment. The results showed that there were various potential pathogenic bacteria in the hospital wastewater, and the abundance and diversity of the influent ARGs in the general hospital were higher than those in the eye hospital. The influent of the eye hospital was mainly composed of Thauera and Pseudomonas, and sul1 (sulfonamide) was the most abundant ARG. The influent of the general hospital contained mainly Aeromonas and Acinetobacter, and tet39 (tetracycline) was the most abundant ARG. Furthermore, co-occurrence network analysis showed that the main bacteria carrying ARGs in hospital wastewater varied with hospital type; the same bacteria in wastewater from different hospitals could carry different ARGs, and the same ARG could also be carried by different bacteria. The changes in the bacterial community and ARG abundance in the effluent from the two hospitals showed that the activated sludge treatment and the direct chlorination disinfection can effectively remove some bacteria and ARGs in wastewater but have limitations. The species diversity increased significantly after the activated sludge treatment, while the direct chlorination disinfection did not increase the diversity. The activated sludge treatment has a better effect on the elimination of ARGs than the direct chlorination disinfection. In summary, we investigated the differences in bacterial communities and ARGs in wastewater from two hospitals exposed to different antibiotic usage conditions, evaluated the effects of different wastewater treatment methods on the bacterial communities and ARGs in hospital wastewater, and recommended appropriate methods for certain clinical environments.202235663906
7391140.9999Antibiotic resistance genes in China: occurrence, risk, and correlation among different parameters. Antibiotic resistance has become a widely concerned issue due to the huge risk on the ecological environment and human health. China has the highest production and consumption of antibiotics than other countries. Thus, antibiotic resistance genes (ARGs) have been detected in various environmental settings (e.g., surface water, wastewater, sediment) in China. The occurrence of ARGs in these matrixes was summarized and discussed in this review. Sulfonamide resistance genes and tetracycline resistance genes were the most frequently detected ARGs in China. According to the abundance of these two classes of ARGs in the natural environment, sulfonamide resistance genes seem to be more stable than tetracycline resistance genes. Furthermore, the relationships between ARGs and antibiotics, antibiotic resistance bacteria (ARB), heavy metals, and environmental parameters (e.g., pH, organics) were also investigated. Specifically, relative abundance of total ARGs was found to correlate well with concentration of total antibiotics in aqueous phase but not in the solid phase (soil, sediment, sludge, and manure). As for relationship between ARGs and ARB, metals, and environmental parameters in different media, due to complex and variable environment, some exhibit positive correlation, some negative, while others no correlation at all. Three potential risks are discussed in the text: transmission to human, synergistic effect of different ARGs, and variability of ARGs. However, due to the complexity of the environment, more work is needed to establish a quantitative approach of ARG risk assessment, which can provide a theoretical support for the management of antibiotics and the protection of human health.201829948704
7311150.9999Sludge as a potential important source of antibiotic resistance genes in both the bacterial and bacteriophage fractions. The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs found in bacteria can become mobilized in bacteriophage particles in the environment. Sludge derived from secondary treatment in wastewater treatment plants (WWTPs) constitutes a concentrated pool of bacteria and phages that are removed during the treatment process. This study evaluates the prevalence of ARGs in the bacterial and phage fractions of anaerobic digested sludge; five ARGs (blaTEM, blaCTX-M, qnrA, qnrS, and sul1) are quantified by qPCR. Comparison between the wastewater and sludge revealed a shift in the prevalence of ARGs (blaTEM and sul1 became more prevalent in sludge), suggesting there is a change in the bacterial and phage populations from wastewater to those selected during the secondary treatment and the later anaerobic mesophilic digestion of the sludge. ARGs densities were higher in the bacterial than in the phage fraction, with high densities in both fractions; particularly for blaTEM and sul1 (5 and 8 log10 gene copies (GC)/g, respectively, in bacterial DNA; 5.5 and 4.4 log10 GC/g, respectively, in phage DNA). These results question the potential agricultural uses of treated sludge, as it could contribute to the spread of ARGs in the environment and have an impact on the bacterial communities of the receiving ecosystem.201424873655
7331160.9999Metagenomics analysis of probable transmission of determinants of antibiotic resistance from wastewater to the environment - A case study. During mechanical-biological treatment, wastewater droplets reach the air with bioaerosols and pose a health threat to wastewater treatment plant (WWTP) employees and nearby residents. Microbiological pollutants and antimicrobial resistance determinants are discharged to water bodies with treated wastewater (TWW), which poses a potential global epidemiological risk. In the present study, the taxonomic composition of microorganisms was analyzed, and the resistome profile and mobility of genes were determined by metagenomic next-generation sequencing in samples of untreated wastewater (UWW), wastewater collected from an activated sludge (AS) bioreactor, TWW, river water collected upstream and downstream from the wastewater discharge point, and in upper respiratory tract swabs collected from WWTP employees. Wastewater and the emitted bioaerosols near WWTP's facilities presumably contributed to the transmission of microorganisms, in particular bacteria of the phylum Actinobacteria and the associated antibiotic resistance genes (ARGs) (including ermB, ant(2″)-I, tetM, penA and cfxA2) to the upper respiratory tract of WWTP employees. The discharged wastewater increased the taxonomic diversity of microorganisms and the concentrations of various ARGs (including bacA, emrE, sul1, sul2 and tetQ) in river water. This study fills in the knowledge gap on the health risks faced by WWTP employees. The study has shown that microbiological pollutants and antimicrobial resistance determinants are also in huge quantities discharged to rivers with TWW, posing a potential global epidemiological threat.202235259375
7380170.9998Assessing visitor use impact on antibiotic resistant bacteria and antibiotic resistance genes in soil and water environments of Rocky Mountain National Park. Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been detected in soil and water in close proximity to anthropogenic sources, but the extent to which human impact plays into ARB and ARGs entering the environment is not well described. This study aimed to determine the impact of visitor use on ARB and ARGs in a national park environment. Soil (n = 240) and water (n = 210) samples were collected across a gradient of human activity in Rocky Mountain National Park and analyzed for bacteria resistant to doxycycline, levofloxacin, and vancomycin. Amount of physical effort required to access a sampling site was used as a metric for the likelihood of human presence. A subset of samples was analyzed for the presence and abundance of six ARGs using quantitative polymerase chain reaction. Linear regression analysis demonstrated that anthropogenic factors including hiking effort and proximity to a toilet significantly contributed to the variance of the abundance of ARB for multiple antibiotics in soil and water. Additionally, ecological factors such as water movement, soil texture, and season may play a role in the detection of ARB and ARGs. Predictive analysis suggests that both human presence and human activities, such as waste elimination, significantly contributed to the abundance of ARB in soil and water. The results of this work evidence that the ecology of antibiotic resistance in remote environments is more complex than anthropogenic impact alone, necessitating further environmental characterization of ARB and ARGs.202133932658
7230180.9998Persistence of antibiotic resistance genes and bacterial community changes in drinking water treatment system: From drinking water source to tap water. As emerging contaminants, antibiotic resistance genes (ARGs) have become a public concern. This study aimed to investigate the occurrence and diversity of ARGs, and variation in the composition of bacterial communities in source water, drinking water treatment plants, and tap water in the Pearl River Delta region, South China. Various ARGs were present in the different types of water. Among the 27 target ARGs, floR and sul1 dominated in source water from three large rivers in the region. Pearson correlation analysis suggested that sul1, sul2, floR, and cmlA could be potential indicators for ARGs in water samples. The total abundance of the detected ARGs in tap water was much lower than that in source water. Sand filtration and sedimentation in drinking water treatment plants could effectively remove ARGs; in contrast, granular activated carbon filtration increased the abundance of ARGs. It was found that Pseudomonas may be involved in the proliferation and dissemination of ARGs in the studied drinking water treatment system. Bacteria and ARGs were still present in tap water after treatment, though they were significantly reduced. More research is needed to optimize the water treatment process for ARG removal.201829127799
3198190.9998Enhance antibiotic resistance and human health risks in aerosols during the COVID-19 pandemic. Aerosols are an important route for the transmission of antibiotic resistance genes (ARGs). Since the 2019 (COVID-19) pandemic, the large-scale use of disinfectants has effectively prevented the spread of environmental microorganisms, but studies regarding the antibiotic resistance of airborne bacteria remain limited. This study focused on four functional urban areas (commercial areas, educational areas, residential areas and wastewater treatment plant) to study the variations in ARG abundances, bacterial community structures and risks to human health during the COVID-19 pandemic in aerosol. The results indicated the abundance of ARGs during the COVID-19 period were up to approximately 13-fold greater than before the COVID-19 period. Large-scale disinfection resulted in a decrease in total bacterial abundance. However, chlorine-resistant bacteria tended to be survived. Among the four functional areas, the diversity and abundance of aerosol bacteria were highest in commercial aera. Antibiotic susceptibility assays suggested elevated resistance of isolated bacteria to several tested antibiotics due to disinfection exposure. The potential exposure risks of ARGs to human health were 2 times higher than before the COVID-19 pandemic, and respiratory intake was the main exposure route. The results highlighted the elevated antibiotic resistance of bacteria in aerosols that were exposed to disinfectants after the COVID-19 pandemic. This study provides theoretical guidance for the rational use of disinfectants and control of antimicrobial resistance.202336754321