# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 7088 | 0 | 1.0000 | Small-scale wastewater treatment plants as a source of the dissemination of antibiotic resistance genes in the aquatic environment. Wastewater treatment plants (WWTPs) are significant source of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which can spread further in the environment by reaching rivers together with effluents discharged from WWTPs. In this study untreated and treated wastewater (UWW, TWW), upstream and downstream river water (URW, DRW) were collected from 4 WWTPs, in the winter and autumn seasons. The occurrence of ARB resistant to beta-lactams and tetracyclines as well as the presence of antibiotics from these classes were analysed in water and wastewater samples. Additionally, the amounts of 12 ARGs, 2 genes of mobile genetic elements (MGEs), gene uidA identifying E. coli and 16S rRNA were also determined. Resistance to beta-lactams prevailed among ARB in water and wastewater samples (constituting 82-88% of total counts of bacteria). The dominant genes in water and wastewater samples were bla(TEM), tetA, sul1. The gene bla(OXA) demonstrated high variability of its concentration in samples collected in both seasons. Despite the high per cent reduction of ARB and ARGs concentration observed during the wastewater treatment processes, their large quantities are still transmitted into the environment. The research focuses on WWTPs' role in the dissemination of ARGs and MGEs in the aquatic environment. | 2020 | 31561123 |
| 7291 | 1 | 0.9999 | Accumulation 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. | 2015 | 25933054 |
| 7331 | 2 | 0.9999 | Metagenomics 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. | 2022 | 35259375 |
| 5329 | 3 | 0.9999 | Distribution of Antibiotic Resistance in a Mixed-Use Watershed and the Impact of Wastewater Treatment Plants on Antibiotic Resistance in Surface Water. The aquatic environment has been recognized as a source of antibiotic resistance (AR) that factors into the One Health approach to combat AR. To provide much needed data on AR in the environment, a comprehensive survey of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues was conducted in a mixed-use watershed and wastewater treatment plants (WWTPs) within the watershed to evaluate these contaminants in surface water. A culture-based approach was used to determine prevalence and diversity of ARB in surface water. Low levels of AR Salmonella (9.6%) and Escherichia coli (6.5%) were detected, while all Enterococcus were resistant to at least one tested antibiotic. Fewer than 20% of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (17.3%) and carbapenem-resistant Enterobacteriaceae (CRE) (7.7%) were recovered. Six ARGs were detected using qPCR, primarily the erythromycin-resistance gene, ermB. Of the 26 antibiotics measured, almost all water samples (98.7%) had detectable levels of antibiotics. Analysis of wastewater samples from three WWTPs showed that WWTPs did not completely remove AR contaminants. ARGs and antibiotics were detected in all the WWTP effluent discharges, indicating that WWTPs are the source of AR contaminants in receiving water. However, no significant difference in ARGs and antibiotics between the upstream and downstream water suggests that there are other sources of AR contamination. The widespread occurrence and abundance of medically important antibiotics, bacteria resistant to antibiotics used for human and veterinary purposes, and the genes associated with resistance to these antibiotics, may potentially pose risks to the local populations exposed to these water sources. | 2023 | 37998788 |
| 7089 | 4 | 0.9999 | Poultry slaughterhouse wastewater as a driver of bacterial community shifts and the spread of antibiotic resistance genes in aquatic ecosystems. Poultry slaughterhouse wastewater (PSW) is a source of environmental pollutants, harboring pathogens and antibiotic resistance genes (ARGs). This study aimed to assess the effects of conventional biological treatment of PSW on the bacterial community and its efficiency in removing ARGs, as well as to evaluate the impact of its discharge on the receiving river. Samples were collected from raw sewage, treated effluent, and upstream and downstream river sites. Total metagenomic DNA was extracted for real-time PCR quantification of 16S rRNA, yccT gene (Escherichia coli), and ARGs, which were selected based on their ability to confer resistance to clinically relevant antibiotics and their prevalence in poultry-associated environments, including resistance to tetracyclines (tetM), beta-lactams (bla(TEM)), sulfonamides (sul1), and quinolones (qnrS). Amplicon sequencing of 16S rRNA V3-V4 region was used to assess bacterial community structure. Treated effluent significantly altered the downstream microbiome, reducing bacterial richness by up to 72.3% and diversity by 25.4%. Effluent-associated phyla such as Pseudomonadota (37%), Bacillota (28%), and Bacteroidota (26%) became dominant in the downstream river samples. Enterobacterales increased after treatment, and E. coli increased by 2.93 logs downstream. All ARGs increased after treatment and remained elevated downstream, with qnrS and sul1 rising by 3.77 and 3.87 logs, respectively. These findings highlight PSW treatment plants as a potential point of selection and dissemination of antimicrobial resistance (AMR)-related bacteria and genes. Inefficient treatment contributes to shifts in river bacterial communities and the spread of AMR. | 2025 | 41165913 |
| 7283 | 5 | 0.9998 | Comparative 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. | 2016 | 27054725 |
| 7087 | 6 | 0.9998 | Antibiotic resistance in shellfish and major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources. | 2021 | 34226964 |
| 7233 | 7 | 0.9998 | Distribution, sources, and potential risks of antibiotic resistance genes in wastewater treatment plant: A review. Irrational use of antibiotics produces a large number of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Wastewater treatment plants (WWTPs) act as important sources and sinks of ARGs, and play an important role in their generation, treatment, and dissemination. This study summarizes the types, concentrations, and factors of ARGs in WWTPs, investigates the sources of ARGs in wastewater, compares the removal efficiencies of different treatment processes on ARGs, and analyzes the potential risks of ARGs accumulation in effluent, sludge and their emission into the air. The results show that the main ARGs detected in the influent of WWTPs are the genes resistant to macrolides (ermB, ermF), tetracyclines (tetW, tetA, tetC), sulfonamides (sul1, sul2), and β-lactams (bla(OXA), bla(TEM)). The concentrations of ARGs in the influent of the WWTPs are 2.23 × 10(2)-3.90 × 10(9) copies/mL. Wastewater quality and microbial community are the dominant factors that affect the distribution characteristics of ARGs. The accumulation of ARGs in effluent, sludge, and aerosols pose potential risks to the regional ecological environment and human health. Based on these results, research trends with respect to ARGs in WWTPs are also prospected. | 2022 | 35921944 |
| 5349 | 8 | 0.9998 | Spread and persistence of antimicrobial resistance genes in wastewater from human and animal sources in São Paulo, Brazil. The spread of antimicrobial resistance (AMR) through multiple reservoirs is a global concern. Wastewater is a critical AMR dissemination source, so this study aimed to assess the persistence of resistance genetic markers in wastewater using a culture-independent approach. Raw and treated wastewater samples (n = 121) from a wastewater treatment plant (WWTP), a human hospital, a veterinary hospital, and a pig farm were monthly collected and concentrated by filtration. DNA was extracted directly from filter membranes, and PCR was used in the qualitative search of 32 antimicrobial resistance genes (ARGs). Selected genes (bla(CTX-M), bla(KPC), qnrB, and mcr-1) were enumerated by quantitative real-time PCR (qPCR). Twenty-six ARGs were detected in the qualitative ARGs search, while quantitative data showed a low variation of the ARG's relative abundance (RA) throughout the months, especially at the human hospital and the WWTP. At the WWTP, despite significantly reducing the absolute number of gene copies/L after each treatment stage (p < 0.05), slight increases (p > 0.05) in the RAs of genes bla(CTX-M), qnrB, and mcr-1 were observed in reused water (tertiary treatment) when compared with secondary effluent. Although the increase is not statistically significant, it is worth noting that there was some level of ARGs concentration after the disinfection process. No significant absolute or relative after-treatment quantification reductions were observed for any ARGs at the veterinary hospital or the pig farm. The spread of ARGs through sewage needs to be continuously addressed, because their release into natural environments may pose potential risks of exposure to resistant bacteria and impact local ecosystems. | 2024 | 38545908 |
| 7272 | 9 | 0.9998 | Determination of antibiotic resistance genes in a WWTP-impacted river in surface water, sediment, and biofilm: Influence of seasonality and water quality. Many pathogenic bacteria are adapted to live in aquatic habitats, which makes rivers possible sources and spread pathways of antibiotic resistance, since they usually receive effluents from wastewater treatment plants (WWTP), possibly containing antibiotic residues and also antibiotic-resistant bacteria. This study investigates different monitoring strategies to identify the occurrence of antibiotic-resistant bacteria in rivers. We analyzed the presence of 13 antibiotic resistance genes (ARGs) and seven gene markers for facultative pathogenic bacteria (FPB) with qPCR in sampling sites upstream and downstream of a small WWTP in Southern Germany. Five sampling campaigns were conducted from February to June 2019. Surface water, sediment, and biofilm samples were analyzed. The biofilm was collected from an artificial sampler placed in the river. bla(TEM), ermB, tetM, and sul1 genes were detected in all samples analyzed. The results showed there was a previous background in the river, but the WWTP and the water quality of the river influenced the concentration and occurrence of ARGs and FPB. Genes representing resistance against strong or last-resort antibiotics, such as mecA, bla(CMY-2), bla(KPC-3), and mcr-1, and multidrug resistance were also detected, mainly in samples collected downstream of the WWTP. Downstream of the WWTP, the occurrence of ARG and FPB correlated with ammoniacal nitrogen, while upstream of the WWTP correlated with turbidity, suspended solids, and seasonal factors such as UVA radiation and the presence of macrophytes. Biofilm samples presented higher abundances of ARGs and FPB. The biofilm sampler was efficient and allowed to collect biofilms from specific periods, which helped to identify seasonal patterns. | 2021 | 33450684 |
| 7290 | 10 | 0.9998 | Study of indiscriminate distribution of restrained antimicrobial resistome of different environmental niches. Prophylactic usage and high persistent nature of several antibiotics have put selective pressure on the native microbial population that led to the emergence, propagation, and persistence of antibiotic resistance in nature. The surveillance of antibiotic resistome pattern and identification of points of intervention throughout the different environmental habitats will help to break the flow of antibiotic resistance from environmental bacteria to human pathogens. The present study compares the occurrence, diversity, and abundance of ARGs in industrial sludge, wetland sludge, and sediment sample contaminated with pharmaceutical discharge. Metagenomes were mined for the presence of ARGs against the ResFinder 3.2 database using BLASTn program. Pharmaceutical sample (2.52%) showed high degree of ARG abundance and richness as compared with ETP sludge (2.28%) and wetland sludge samples (1.29%). The modern resistome pattern represented by critically important resistance genes against tetracycline (tetA, tetC, tetW, tetT, and tetS/M) and quinolone (qnrS, qnrVC, and qnrD) was identified in pharmaceutical sediment sample. However, effluent treatment plant (ETP) sludge sample showed abundance of multidrug efflux pumps indicating the presence of primitive resistome profile. In conclusion, the indiscriminate distribution pattern of antibiotic resistance genes in three selected environmental sites suggests enrichment and distribution of environmental niche-driven resistance. The study also suggests effluent discharge site from pharmaceutical industries and ETPs as pivotal points of intervention for the mitigation of antibiotic resistance. | 2021 | 33099734 |
| 7227 | 11 | 0.9998 | High-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. | 2023 | 37267763 |
| 5351 | 12 | 0.9998 | Bacterial hosts of clinically significant beta-lactamase genes in Croatian wastewaters. Wastewater treatment plants (WWTPs) provide a suitable environment for the interaction of antibiotic resistant bacteria and antibiotic-resistance genes (ARGs) from human, animal, and environmental sources. The aim was to study the influent and effluent of two WWTPs in Croatia to identify bacterial hosts of clinically important beta-lactamase genes (blaTEM, blaVIM, blaOXA-48-like) and observe how their composition changes during the treatment process. A culture-independent epicPCR (Emulsion, Paired isolation and Concatenation Polymerase Chain Reaction) was used to identify the ARG hosts, and 16S rRNA amplicon sequencing to study the entire bacterial community. Different wastewater sources contributed to the significant differences in bacterial composition of the wastewater between the two WWTPs studied. A total of 167 genera were detected by epicPCR, with the Arcobacter genus, in which all ARGs studied were present, dominating in both WWTPs. In addition, the clinically important genera Acinetobacter and Aeromonas contained all ARGs examined. The blaOXA-48-like gene had the highest number of hosts, followed by blaVIM, while blaTEM had the narrowest host range. Based on 16S rRNA gene sequencing, ARG hosts were detected in both abundant and rare taxa. The number of hosts carrying investigated ARGs was reduced by wastewater treatment. EpicPCR provided valuable insights into the bacterial hosts of horizontally transmissible beta-lactamase genes in Croatian wastewater. | 2024 | 38796694 |
| 7093 | 13 | 0.9998 | Class 1 integrase, sulfonamide and tetracycline resistance genes in wastewater treatment plant and surface water. Wastewater treatment plants are considered hot spots for multiplication and dissemination of antibiotic-resistant bacteria and resistance genes. In this study, we determined the presence of class 1 integron integrase and genes conferring resistance to tetracyclines and sulfonamides in the genomes of culturable bacteria isolated from a wastewater treatment plant and the river that receives the treated wastewater. Moreover, using PCR-based metagenomic approach, we quantified intI1, tet and sul genes. Wastewater treatment caused the decrease in the total number of culturable heterotrophs and bacteria resistant to tetracycline and sulfonamides, along with the decrease in the number of intI1, sul and tet gene copies per ml, with significant reduction of tet(B). On the other hand, the treatment process increased both the frequency of tetracycline- and sulfonamide-resistant bacteria and intI1-positive strains, and the relative abundance of all quantified antibiotic resistance genes (ARGs) and intI1 gene; in the case of tet(A) and sul2 significantly. The discharge of treated wastewater increased the number of intI1, tet and sul genes in the receiving river water both in terms of copy number per ml and relative abundance. Hence, despite the reduction of the number of ARGs and ARBs, wastewater treatment selects for bacteria with ARGs in effluent. | 2016 | 26519797 |
| 5323 | 14 | 0.9998 | Monitoring and assessing the impact of wastewater treatment on release of both antibiotic-resistant bacteria and their typical genes in a Chinese municipal wastewater treatment plant. Wastewater treatment plants (WWTPs) are important hotspots for the spread of antibiotic resistance. However, the release and impact factors of both antibiotic resistant bacteria and the relevant genes over long periods in WWTPs have rarely been investigated. In this study, the fate of bacteria and genes resistant to six commonly used antibiotics was assessed over a whole year. In WWTP effluent and biosolids, a high prevalence of heterotrophic bacteria resistant to vancomycin, cephalexin, sulfadiazine and erythromycin were detected, each with a proportion of over 30%. The corresponding genes (vanA, ampC, sulI and ereA) were all detected in proportions of (2.2 ± 0.8) × 10(-10), (6.2 ± 3.2) × 10(-9), (1.2 ± 0.8) × 10(-7) and (7.6 ± 4.8) × 10(-8), respectively, in the effluent. The sampling season imposed considerable influence on the release of all ARB. High release loads of most ARB were detected in the spring, while low release loads were generally found in the winter. In comparison, the ARG loads changed only slightly over various seasons. No statistical relevance was found between all ARB abundances and their corresponding genes over the long-term investigation period. This inconsistent behavior indicates that bacteria and genes should both be considered when exploring resistance characteristics in wastewater. A redundancy analysis was adopted to assess the impact of wastewater quality and operational conditions on antibiotic resistance. The results indicated that most ARB and ARG proportions were positively related to the COD and turbidity of the raw sewage, while negatively related to those of the effluent. DO and temperature exhibited strong negative relevance to most ARB prevalence. | 2014 | 24927359 |
| 7186 | 15 | 0.9998 | Removal of selected sulfonamides and sulfonamide resistance genes from wastewater in full-scale constructed wetlands. Sulfonamides are high-consumption antibiotics that reach the aquatic environment. The threat related to their presence in wastewater and the environment is not only associated with their antibacterial properties, but also with risk of the spread of drug resistance in bacteria. Therefore, the aim of this work was to evaluate the occurrence of eight commonly used sulfonamides, sulfonamide resistance genes (sul1-3) and integrase genes intI1-3 in five full-scale constructed wetlands (CWs) differing in design (including hybrid systems) and in the source of wastewater (agricultural drainage, domestic sewage/surface runoff, and animal runs runoff in a zoo). The CWs were located in low-urbanized areas in Poland and in Czechia. No sulfonamides were detected in the CW treating agricultural tile drainage water. In the other four systems, four sulfonamide compounds were detected. Sulfamethoxazole exhibited the highest concentration in those four CWs and its highest was 12,603.23 ± 1000.66 ng/L in a CW treating a mixture of domestic sewage and surface runoff. Despite the high removal efficiencies of sulfamethoxazole in the tested CWs (86 %-99 %), it was still detected in the treated wastewater. The sul1 genes occurred in all samples of raw and treated wastewater and their abundance did not change significantly after the treatment process and it was, predominantly, at the level 10(5) gene copies numbers/mL. Noteworthy, sul2 genes were only found in the influents, and sul3 were not detected. The sulfonamides can be removed in CWs, but their elimination is not complete. However, hybrid CWs treating sewage were superior in decreasing the relative abundance of genes and the concentration of SMX. CWs may play a role in the dissemination of sulfonamide resistance genes of the sul1 type and other determinants of drug resistance, such as the intI1 gene, in the environment, however, the magnitude of this phenomenon is a matter of further research. | 2024 | 38081427 |
| 7229 | 16 | 0.9998 | Occurrence 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. | 2023 | 36527555 |
| 7232 | 17 | 0.9998 | Occurrence and prevalence of antibiotic resistance in landfill leachate. Antibiotic resistance (AR) is extensively present in various environments, posing emerging threat to public and environmental health. Landfill receives unused and unwanted antibiotics through household waste and AR within waste (e.g., activated sludge and illegal clinical waste) and is supposed to serve as an important AR reservoir. In this study, we used culture-dependent methods and quantitative molecular techniques to detect and quantify antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in 12 landfill leachate samples from six geographic different landfills, China. Five tested ARGs (tetO, tetW, bla(TEM), sulI, and sulII) and seven kinds of antibiotic-resistant heterotrophic ARB were extensively detected in all samples, demonstrating their occurrence in landfill. The detected high ratio (10(-2) to 10(-5)) of ARGs to 16S ribosomal RNA (rRNA) gene copies implied that ARGs are prevalent in landfill. Correlation analysis showed that ARGs (tetO, tetW, sulI, and sulII) significantly correlated to ambient bacterial 16S rRNA gene copies, suggesting that the abundance of bacteria in landfill leachate may play an important role in the horizontal spread of ARGs. | 2015 | 25903180 |
| 7330 | 18 | 0.9998 | Deterministic assembly process dominates bacterial antibiotic resistome in wastewater effluents receiving river. Antibiotic resistance has become a concerning global health challenge, such as the dissemination of bacteria and genes between humans and the environments. Wastewater treatment plants (WWTPs) effluents, as significant reservoirs for antimicrobial resistant bacteria and antibiotic resistance genes (ARGs), pose critical risks to public health. However, whether wastewater effluent prominently contributes to the abundance of ARGs and their community assembly processes in receiving river has yet been unclear. Here we investigated the effects of the effluent discharge on the ARGs and their associate microbial community in the receiving river (Qinhuai River, Nanjing) of upstream and 2000 m downstream of one WWTPs discharge point. Results revealed that the total antibiotic concentrations of all sediment samples ranged from 37.86 to 76.11 µg/kg dw, while antibiotic concentrations and ARG abundances in the river near the wastewater discharge site were significantly higher than that of the downstream receiving river. The metagenomic assembly obtained 245 ARGs associated with 19 antibiotic types in the receiving river. Network analyses confirmed that Proteobacteria, Firmicutes, Acidobacteria, and Bacteroides were the key phylum and positively correlated with the antibiotic resistome. Additionally, the bacterial pathogens of the receiving river were identified as the most frequent strains of clinically relevant antibacterial resistance, such as Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Using null modeling analysis to determine the quantification of ecological processes, the results showed that heterogeneous environmental selection (81.81%) was a dominate role of the ecological mechanisms determining the ARG community reconstruction in the receiving river. Our results may contribute to control the environmental dissemination of antimicrobial resistance risks in aquatic environments. | 2022 | 35864403 |
| 7282 | 19 | 0.9998 | Sewers as potential reservoirs of antibiotic resistance. Wastewater transport along sewers favors the colonization of inner pipe surfaces by wastewater-derived microorganisms that grow forming biofilms. These biofilms are composed of rich and diverse microbial communities that are continuously exposed to antibiotic residues and antibiotic resistant bacteria (ARB) from urban wastewater. Sewer biofilms thus appear as an optimal habitat for the dispersal and accumulation of antibiotic resistance genes (ARGs). In this study, the concentration of antibiotics, integron (intI1) and antibiotic resistance genes (qnrS, sul1, sul2, bla(TEM), bla(KPC), ermB, tetM and tetW), and potential bacterial pathogens were analyzed in wastewater and biofilm samples collected at the inlet and outlet sections of a pressurized sewer pipe. The most abundant ARGs detected in both wastewater and biofilm samples were sul1 and sul2 with roughly 1 resistance gene for each 10 copies of 16s RNA gene. Significant differences in the relative abundance of gene intI1 and genes conferring resistance to fluoroquinolones (qnrS), sulfonamides (sul1 and sul2) and betalactams (bla(TEM)) were only measured between inlet and outlet biofilm samples. Composition of bacterial communities also showed spatial differences in biofilms and a higher prevalence of Operational Taxonomic Units (OTUs) with high sequence identity (>98%) to well-known human pathogens was observed in biofilms collected at the inlet pipe section. Our study highlights the role of sewer biofilms as source and sink of ARB and ARGs and supports the idea that community composition rather than antibiotic concentration is the main factor driving the diversity of the sewage resistome. | 2017 | 28709370 |