# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 3542 | 0 | 0.9792 | Fecal indicators, pathogens, antibiotic resistance genes, and ecotoxicity in Galveston Bay after Hurricane Harvey. Unprecedented rainfall after Hurricane Harvey caused a catastrophic flood in the southern coast of Texas, and flushed significant floodwater and sediments into Galveston Bay, the largest estuary along the Texas Gulf Coast. This study investigated the immediate and long-term (6 months post-Harvey) fecal indicators, pathogenic bacteria, antibiotic resistance genes (ARGs), and ecotoxicity in the Galveston Bay. Dramatic decrease of salinity profile to zero, increased levels of fecal indicator bacteria and pathogenic bacteria, and detection of various ARGs were observed in the water and sediment samples collected 2 weeks post-Harvey. High levels of Bla(TEM) and cytotoxicity measured by yeast bioluminescent assay (BLYR) were also observed especially near the river mouths. While Vibrio spp. was dominant in water, much higher abundance of fecal indicator bacteria and pathogen were detected in the sediments. A decreasing trend of Bla(TEM) and cytotoxicity was observed in March 2018 samples, suggesting the Bay has returned to its pre-hurricane conditions 6 months post-Harvey. Interestingly, the abundance of fecal indicator bacteria and pathogens were shifted dramatically according to high-streamflow and low-streamflow seasons in the Bay. The data are useful to construct the model of risk assessment in coastal estuaries system and predict the effects of extreme flooding events in the future. | 2021 | 33445049 |
| 7133 | 1 | 0.9781 | Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario. The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p < 0.05). Decaying and free-floating Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research. | 2017 | 28192677 |
| 3074 | 2 | 0.9773 | Metagenomic analysis of microbial communities and antibiotic resistant genes in the Tijuana river, and potential sources. The Tijuana River is a transborder river that flows northwest across the border from Baja California in Mexico into Southern California before discharging into the Pacific Ocean. The river is frequently contaminated with raw sewage due to inadequate sanitary infrastructure in Tijuana. To assess the type and degree of microbial contamination, water samples were collected monthly from a near-border and an estuarine site from August 2020 until May 2021. A portion of each sample was used for epifluorescent microscopy and DNA was extracted directly from the rest for shotgun metagenomic sequencing. After sequence quality checking and processing, we used the rapid taxonomic identifier tool Kaiju to characterize the microbial diversity of the metagenomes and matched the sequences against the Comprehensive Antibiotic Resistance Database (CARD) to examine antimicrobial resistance genes (ARGs). Bacterial and viral-like particle (VLP) abundance was consistently higher in the near-border samples than in the estuarine samples, while alpha diversity (within sample biodiversity) was higher in estuarine samples. Beta-diversity analysis found clear compositional separation between samples from the two sites, and the near-border samples were more dissimilar to one another than were the estuarine sites. Near-border samples were dominated by fecal-associated bacteria and bacteria associated with sewage sludge, while estuarine sites were dominated by marine bacteria. ARGs were more abundant at the near-border site, but were also readily detectable in the estuarine samples, and the most abundant ARGs had multi-resistance to beta-lactam antibiotics. SourceTracker analysis identified human feces and sewage sludge to be the largest contributors to the near-border samples, while marine waters dominated estuarine samples except for two sewage overflow dates with high fecal contamination. Overall, our research determined human sewage microbes to be common in the Tijuana River, and the prevalence of ARGs confirms the importance of planned infrastructure treatment upgrades for environmental health. | 2024 | 38043772 |
| 6794 | 3 | 0.9773 | Beyond cyanotoxins: increased Legionella, antibiotic resistance genes in western Lake Erie water and disinfection-byproducts in their finished water. BACKGROUND: Western Lake Erie is suffering from harmful cyanobacterial blooms, primarily toxic Microcystis spp., affecting the ecosystem, water safety, and the regional economy. Continued bloom occurrence has raised concerns about public health implications. However, there has been no investigation regarding the potential increase of Legionella and antibiotic resistance genes in source water, and disinfection byproducts in municipal treated drinking water caused by these bloom events. METHODS: Over 2 years, source water (total n = 118) and finished water (total n = 118) samples were collected from drinking water plants situated in western Lake Erie (bloom site) and central Lake Erie (control site). Bloom-related parameters were determined, such as microcystin (MC), toxic Microcystis, total organic carbon, N, and P. Disinfection byproducts (DBPs) [total trihalomethanes (THMs) and haloacetic acids (HAAs)] were assessed in finished water. Genetic markers for Legionella, antibiotic resistance genes, and mobile genetic elements were quantified in source and finished waters. RESULTS: Significantly higher levels of MC-producing Microcystis were observed in the western Lake Erie site compared to the control site. Analysis of DBPs revealed significantly elevated THMs concentrations at the bloom site, while HAAs concentrations remained similar between the two sites. Legionella spp. levels were significantly higher in the bloom site, showing a significant relationship with total cyanobacteria. Abundance of ARGs (tetQ and sul1) and mobile genetic elements (MGEs) were also significantly higher at the bloom site. DISCUSSION: Although overall abundance decreased in finished water, relative abundance of ARGs and MGE among total bacteria increased after treatment, particularly at the bloom site. The findings underscore the need for ongoing efforts to mitigate bloom frequency and intensity in the lake. Moreover, optimizing water treatment processes during bloom episodes is crucial to maintain water quality. The associations observed between bloom conditions, ARGs, and Legionella, necessitate future investigations into the potential enhancement of antibiotic-resistant bacteria and Legionella spp. due to blooms, both in lake environments and drinking water distribution systems. | 2023 | 37700867 |
| 3545 | 4 | 0.9772 | Fecal indicators and antibiotic resistance genes exhibit diurnal trends in the Chattahoochee River: Implications for water quality monitoring. Water bodies that serve as sources of drinking or recreational water are routinely monitored for fecal indicator bacteria (FIB) by state and local agencies. Exceedances of monitoring thresholds set by those agencies signal likely elevated human health risk from exposure, but FIB give little information about the potential source of contamination. To improve our understanding of how within-day variation could impact monitoring data interpretation, we conducted a study at two sites along the Chattahoochee River that varied in their recreational usage and adjacent land-use (natural versus urban), collecting samples every 30 min over one 24-h period. We assayed for three types of microbial indicators: FIB (total coliforms and Escherichia coli); human fecal-associated microbial source tracking (MST) markers (crAssphage and HF183/BacR287); and a suite of clinically relevant antibiotic resistance genes (ARGs; blaCTX-M, blaCMY, MCR, KPC, VIM, NDM) and a gene associated with antibiotic resistance (intl1). Mean levels of FIB and clinically relevant ARGs (blaCMY and KPC) were similar across sites, while MST markers and intI1 occurred at higher mean levels at the natural site. The human-associated MST markers positively correlated with antibiotic resistant-associated genes at both sites, but no consistent associations were detected between culturable FIB and any molecular markers. For all microbial indicators, generalized additive mixed models were used to examine diurnal variability and whether this variability was associated with environmental factors (water temperature, turbidity, pH, and sunlight). We found that FIB peaked during morning and early afternoon hours and were not associated with environmental factors. With the exception of HF183/BacR287 at the urban site, molecular MST markers and intI1 exhibited diurnal variability, and water temperature, pH, and turbidity were significantly associated with this variability. For blaCMY and KPC, diurnal variability was present but was not correlated with environmental factors. These results suggest that differences in land use (natural or urban) both adjacent and upstream may impact overall levels of microbial contamination. Monitoring agencies should consider matching sample collection times with peak levels of target microbial indicators, which would be in the morning or early afternoon for the fecal associated indicators. Measuring multiple microbial indicators can lead to clearer interpretations of human health risk associated with exposure to contaminated water. | 2022 | 36439800 |
| 7276 | 5 | 0.9772 | Antibiotic resistance in urban and hospital wastewaters and their impact on a receiving freshwater ecosystem. The main objective of this study was to investigate the antibiotic resistance (AR) levels in wastewater (WW) and the impact on the receiving river. Samples were collected once per season over one year in the WW of a hospital, in the raw and treated WW of two wastewater treatment plants (WWTPs), as well as upstream and downstream from the release of WWTPs effluents into the Zenne River (Belgium). Culture-dependent methods were used to quantify Escherichia coli and heterotrophic bacteria resistant to amoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. Six antibiotic resistance genes (ARGs) were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that WWTPs efficiently removed antibiotic resistant bacteria (ARB) regardless of its AR profile. The ARGs levels were the highest in the hospital WW and were significantly reduced in both WWTPs. However, ARB and ARGs abundances significantly increased into the Zenne River downstream from the WWTPs outfalls. The variation in the relative abundance of ARGs through WW treatment differed depending on the WWTP, fraction, and gene considered. The sul1 and sul2 genes in PAB fraction showed significantly higher relative abundances in the effluent compared to the influent of both WWTPs. This study demonstrated that WWTPs could be hotspots for AR spread with significant impacts on receiving freshwater ecosystems. This was the first comprehensive study investigating at the same time antibiotics occurrence, fecal bacteria indicators, heterotrophic bacterial communities, and ARGs (distinguishing PAB and FLB) to assess AR levels in WW and impacts on the receiving river. | 2018 | 29730567 |
| 3069 | 6 | 0.9771 | The hospital sink drain biofilm resistome is independent of the corresponding microbiota, the environment and disinfection measures. In hospitals, the transmission of antibiotic-resistant bacteria (ARB) may occur via biofilms present in sink drains, which can lead to infections. Despite the potential role of sink drains in the transmission of ARB in nosocomial infections, routine surveillance of these drains is lacking in most hospitals. As a result, there is currently no comprehensive understanding of the transmission of ARB and the dissemination of antimicrobial resistance genes (ARGs) and associated mobile genetic elements (MGEs) via sink drains. This study employed a multifaceted approach to monitor the total aerobic bacteria as well as the presence of carbapenemase-producing Enterobacterales (CPEs), the microbiota and the resistome of sink drain biofilms (SDBs) and hospital wastewater (WW) of two separate intensive care units (ICUs) in the same healthcare facility in France. Samples of SDB and WW were collected on a monthly basis, from January to April 2023, in the neonatal (NICU) and the adult (AICU) ICUs of Grenoble Alpes University Hospital. In the NICU, sink drain disinfection with surfactants was performed routinely. In the AICU, routine disinfection is not carried out. Culturable aerobic bacteria were quantified on non-selective media, and CPEs were screened using two selective agars. Isolates were identified by MALDI-TOF MS, and antibiotic susceptibility testing (AST) was performed on Enterobacterales and P. aeruginosa. The resistome was analyzed by high-throughput qPCR targeting >80 ARGs and MGEs. The overall bacterial microbiota was assessed via full-length 16S rRNA sequencing. No CPEs were isolated from SDBs in either ICU by bacterial culture. Culture-independent approaches revealed an overall distinct microbiota composition of the SDBs in the two ICUs. The AICU SDBs were dominated by pathogens containing Gram-negative bacterial genera including Pseudomonas, Stenotrophomona, Klebsiella, and Gram-positive Staphylococcus, while the NICU SDBs were dominated by the Gram-negative genera Achromobacter, Serratia, and Acidovorax, as well as the Gram-positive genera Weisella and Lactiplantibacillus. In contrast, the resistome of the SDBs exhibited no significant differences between the two ICUs, indicating that the abundance of ARGs and MGEs is independent of microbiota composition and disinfection practices. The AICU WW exhibited more distinct aerobic bacteria than the NICU WW. In addition, the AICU WW yielded 15 CPEs, whereas the NICU WW yielded a single CPE. All the CPEs were characterized at the species level. The microbiota of the NICU and AICU WW samples differed from their respective SDBs and exhibited distinct variations over the four-month period:the AICU WW contained a greater number of genes conferring resistance to quinolones and integron integrase genes, whereas the NICU WW exhibited a higher abundance of streptogramin resistance genes. Our study demonstrated that the resistome of the hospital SDBs in the two ICUs of the investigated healthcare institute is independent of the microbiota, the environment, and the local disinfection measures. However, the prevalence of CPEs in the WW pipes collecting the waste from the investigated drains differed. These findings offer valuable insights into the resilience of resistance genes in SDBs in ICUs, underscoring the necessity for innovative strategies to combat antimicrobial resistance in clinical environments. | 2025 | 40483807 |
| 7215 | 7 | 0.9770 | High-throughput qPCR profiling of antimicrobial resistance genes and bacterial loads in wastewater and receiving environments. Wastewater treatment plants (WWTPs) are hot spots for the acquisition and spread of antimicrobial resistance (AMR). This regional-based study quantified antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and bacteria in hospital and community-derived wastewater and receiving environments, using high-throughput qPCR (HT-qPCR). This is the first study to apply Resistomap's Antibiotic Resistance Gene Index (ARGI) as a standardised metric to find the overall AMR level across different WWTPs. ARGI of WWTPs ranged from 2.0 to 2.3, indicating higher relative ARG levels than the mean European ARGI of 2.0, but lower than the global mean of 2.4. The highest diversity and abundance of ARGs were observed in untreated hospital and community wastewater. The reduction of total ARGs during wastewater treatment (0.2-2 logs) and bacteria (0.3-1.5 logs) varied spatio-temporally across the WWTPs. Despite a decrease in ARG and bacterial abundance in treated effluents, substantial loads were still released into receiving environments. Notably, ARG levels in coastal sediments were comparable to those in untreated wastewater, and most ARGs were shared between wastewater and receiving environments, highlighting the impact of wastewater discharge on these ecosystems. Sewage outfall exposure increased ARGs in shellfish, emphasising risks to shellfish hygiene. This study provides evidence to inform policymaking, emphasising advanced wastewater treatment methods and combined sewer overflow (CSO) management to mitigate ARG release, protecting water users and the food chain. | 2025 | 40127809 |
| 3543 | 8 | 0.9767 | Precipitation influences pathogenic bacteria and antibiotic resistance gene abundance in storm drain outfalls in coastal sub-tropical waters. Stormwater contamination can threaten the health of aquatic ecosystems and human exposed to runoff via nutrient and pathogen influxes. In this study, the concentrations of 11 bacterial pathogens and 47 antibiotic resistance genes (ARGs) were determined by using high-throughput microfluidic qPCR (MFQPCR) in several storm drain outfalls (SDOs) during dry and wet weather in Tampa Bay, Florida, USA. Data generated in this study were also compared with the levels of fecal indicator bacteria (FIB) and sewage-associated molecular markers (i.e., Bacteroides HF183 and crAssphage markers) in same SDOs collected in a recent study (Ahmed et al., 2018). Concentration of FIB, sewage-associated markers, bacterial pathogens and many ARGs in water samples were relatively high and SDOs may be potentially hotspots for microbial contamination in Tampa Bay. Mean concentrations of culturable E. coli and Enterococcus spp. were tenfold higher in wet compared to dry weather. The majority of microbiological contaminants followed this trend. E. coli eaeA, encoding the virulence factor intimin, was correlated with levels of 20 ARGs, and was more frequently detected in wet weather than dry weather samples. The bla(KPC) gene associated with carbapenem resistant Enterobacteriaceae and the beta-lactam resistant gene (bla(NPS)) were only detected in wet weather samples. Frequency of integron genes Intl2 and Intl3 detection increased by 42% in wet weather samples. Culturable E. coli and Enterococcus spp. significantly correlated with 19 of 47 (40%) ARG tested. Sewage-associated markers crAssphage and HF183 significantly correlated (p < 0.05) with the following ARGs: intl1, sul1, tet(M), ampC, mexB, and tet(W). The presence of sewage-associated marker genes along with ARGs associated with sewage suggested that aging sewage infrastructure contributed to contaminant loading in the Bay. Further research should focus on collecting spatial and temporal data on the microbiological contaminants especially viruses in SDOs. | 2018 | 29754026 |
| 3073 | 9 | 0.9766 | A watershed impacted by anthropogenic activities: Microbial community alterations and reservoir of antimicrobial resistance genes. Water is the main resource for maintaining life. Anthropic activities influence the microbial epidemiological chain in watersheds, which can act as ways of disseminating microorganisms resistant to antimicrobial drugs, with impacts on human, animal, and environmental health. Here, we characterized aquatic microbial communities and their resistomes in samples collected along Rio das Ostras watershed during two seasons. Surface water samples were collected at eleven sites from the Jundiá, Iriry, and Rio das Ostras rivers in two seasons (dry and wet season). Microbial DNA was extracted, high-throughput sequenced and screened for antimicrobial resistance genetic (ARG) markers. The physicochemical characteristics and the microbiota data confirmed that Rio das Ostras watershed can be divided into three well defined portions: rural, urban, and marine. Rural areas were enriched by bacteria typically found in limnic environments and Patescibacteria phyla. The urban portion was characterized by sites with low pH and groups associated with iron oxidation. Some genera of clinical relevance were also identified, though in relatively low abundance. The marine site was enriched mainly by Cyanobacteria and bacteria that showed strong correlation with conductivity, salinity, and chloride. Twenty-six ARG markers were identified on the resistome, being found most frequently in the urban area, despite being present in rural sites. Among them were some related to classes of great clinical concern, such as genes coding for extended-spectrum beta-lactamase (bla(CTX-M) and bla(TEM)), resistance to carbapenems (bla(KPC)) and to methicillin by Staphylococcus aureus (mecA). These results broaden our understanding of the microbial community of a watershed impacted by anthropogenic actions. The large number of ARGs detected along the Rio das Ostras watershed contrasts with the small number of microorganisms of clinical relevance observed, suggesting that antimicrobial resistance has arisen from non-clinical environments and microbes. Our results corroborate that freshwater acts as a reservoir of antimicrobial resistance genes. | 2021 | 34328962 |
| 3075 | 10 | 0.9765 | Comparison of environmental microbiomes in an antibiotic resistance-polluted urban river highlights periphyton and fish gut communities as reservoirs of concern. Natural waterways near urban areas are heavily impacted by anthropogenic activities, including their microbial communities. A contaminant of growing public health concern in rivers is antibiotic resistant genes (ARGs), which can spread between neighboring bacteria and increase the potential for transmission of AR bacteria to animals and humans. To identify the matrices of most concern for AR, we compared ARG burdens and microbial community structures between sample types from the Scioto River Watershed, Ohio, the United States, from 2017 to 2018. Five environmental matrices (water, sediment, periphyton, detritus, and fish gut) were collected from 26 river sites. Due to our focus on clinically relevant ARGs, three carbapenem resistance genes (bla(KPC), bla(NDM), and bla(OXA-48)) were quantified via DropletDigital™ PCR. At a subset of nine urbanized sites, we conducted16S rRNA gene sequencing and functional gene predictions. Carbapenem resistance genes were quantified from all matrices, with bla(KPC) being the most detected (88 % of samples), followed by bla(NDM) (64 %) and bla(OXA-48) (23 %). Fish gut samples showed higher concentrations of bla(KPC) and bla(NDM) than any other matrix, indicating potential ARG bioaccumulation, and risk of broader dissemination through aquatic and nearshore food webs. Periphyton had higher concentrations of bla(NDM) than water, sediment, or detritus. Microbial community analysis identified differences by sample type in community diversity and structure. Sediment samples had the most diverse microbial communities, and detritus, the least. Spearman correlations did not reveal significant relationships between the concentrations of the monitored ARGs and microbial community diversity. However, several differentially abundant taxa and microbial functions were identified by sample type that is definitive of these matrices' roles in the river ecosystem and habitat type. In summary, the fish gut and periphyton are a concern as AR reservoirs due to their relatively high concentration of carbapenem resistance genes, diverse microbial communities, and natural functions that promote AR. | 2022 | 35973543 |
| 7351 | 11 | 0.9765 | Dynamics of integron structures across a wastewater network - Implications to resistance gene transfer. Class 1 and other integrons are common in wastewater networks, often being associated with antibiotic resistance genes (ARGs). However, the importance of different integron structures in ARG transfer within wastewater systems has only been implied, especially between community and hospital sources, among wastewater treatment plant compartments, and in receiving waters. This uncertainty is partly because current clinical class 1 integron qPCR assays (i.e., that target human-impacted structures, i.e., clintI1) poorly delineate clintI1 from non-impacted class 1 integron structures. They also say nothing about their ARG content. To fill these technical gaps, new real-time qPCR assays were developed for "impacted" class 1 structures (called aint1; i.e., anthropogenic class 1 integrons) and empty aint1 structures (i.e., carry no ARGs; called eaint1). The new assays and other integron assays then were used to examine integron dynamics across a wastewater network. 16S metagenomic sequencing also was performed to characterise associated microbiomes. aint1 abundances per bacterial cell were about 10 times greater in hospital wastewaters compared with other compartments, suggesting aint1 enrichment with ARGs in hospital sources. Conversely, the relative abundance of eaint1 structures were over double in recycled activated sludge compared with other compartments, except receiving waters (RAS; ∼30% of RAS class 1 structures did not carry ARGs). Microbiome analysis showed that human-associated bacterial taxa with mobile integrons also differed in RAS and river sediments. Further, class 1 integrons in RAS bacteria appear to have released ARGs, whereas hospital bacteria have accumulated ARGs. Results show that quantifying integron dynamics can help explain where ARG transfer occurs in wastewater networks, and should be considered in future studies on antibiotic resistance in the environment. | 2021 | 34673462 |
| 7081 | 12 | 0.9765 | Seasonal variations in export of antibiotic resistance genes and bacteria in runoff from an agricultural watershed in Iowa. Seasonal variations of antimicrobial resistance (AMR) indicators in runoff water can help improve our understanding of AMR sources and transport within an agricultural watershed. This study aimed to monitor multiple areas throughout the Black Hawk Lake (BHL) watershed (5324 ha) in central Iowa during 2017 and 2018 that consists of both swine and cattle feeding operations as well as known areas with manure application. The measured indicators included plate counts for fecal indicator bacteria (FIB) E. coli, Enterococcus, antibiotic resistant fecal indicator bacteria (ARBs) tylosin resistant Enterococcus, tetracycline resistant Enterococcus, and antibiotic resistance genes (ARGs): ermB, ermF (macrolide), tetA, tetM, tetO, tetW (tetracycline), sul1, sul2 (sulfonamide), aadA2 (aminoglycoside), vgaA, and vgaB (pleuromutilin). Both the plate count and the ARG analyses showed seasonal trends. Plate counts were significantly greater during the growing season, while the ARGs were greater in the pre-planting and post-harvest seasons (Wilcoxon Rank-Sum Test p < 0.05). The ermB gene concentration was significantly correlated (p < 0.05) with E. coli and Enterococcus concentrations in 2017, suggesting a potential use of this ARG as an indicator of environmental AMR and human health risk. Flow rate was not a significant contributor to annual variations in bacteria and AMR indicators. Based on observed seasonal patterns, we concluded that manure application was the likely contributor to elevated ARG indicators observed in the BHL watershed, while the driver of elevated ARB indictors in the growing season can only be speculated. Understanding AMR export patterns in agricultural watersheds provides public health officials knowledge of seasonal periods of higher AMR load to recreational waters. | 2020 | 32806354 |
| 7164 | 13 | 0.9765 | Anthropogenic pressures amplify high-risk antibiotic resistome via co-selection among biocide resistance, virulence, and antibiotic resistance genes in the Ganjiang River basin: Drivers diverge in densely versus sparsely populated reaches. As the largest river in the Poyang Lake system, the Ganjiang River faces escalating anthropogenic pressures that amplify resistance gene dissemination. This study integrated antibiotic resistance genes (ARGs), biocide resistance genes (BRGs), and virulence factor genes (VFGs) to reveal their co-selection mechanisms and divergent environmental drivers between densely (DES) and sparsely populated (SPAR) regions of the Ganjiang River basin. The microbial and viral communities and structures differed significantly between the DES and SPAR regions (PERMANOVA, p < 0.001). Midstream DES areas were hotspots for ARGs/BRGs/VFGs enrichment, with peak enrichment multiples reaching 10.2, 5.7, and 5.9-fold respectively. Procrustes analysis revealed limited dependence of ARGs transmission on mobile genetic elements (MGEs) (p > 0.05). Separately, 74 % of dominant ARGs (top 1 %) showed strong correlations with BRGs (r(2) = 0.973, p < 0.01) and VFGs (r(2) = 0.966, p < 0.01) via co-selection. Pathogenic Pseudomonas spp. carrying multidrug-resistant ARGs, BRGs, and adhesion-VFGs were identified as high-risk vectors. In SPAR areas, anthropogenic pressure directly dominated ARGs risk (RC = 54.2 %, β = 0.39, p < 0.05), with biological factors as secondary contributors (RC = 45.8 %, β = 0.33, p < 0.05). In contrast, DES regions showed anthropogenic pressure exerting broader, enduring influences across microorganisms, physicochemical parameters, and biological factors, escalating ARGs risks through diverse pathways, with BRGs/VFGs acting as direct drivers. This study proposes establishing a risk prevention system using BRGs and pathogenic microorganisms as early-warning indicators. | 2025 | 40858019 |
| 7333 | 14 | 0.9764 | Metagenomics unveils the role of hospitals and wastewater treatment plants on the environmental burden of antibiotic resistance genes and opportunistic pathogens. Antimicrobial resistance (AMR) is a global health challenge, with hospitals and wastewater treatment plants (WWTPs) serving as significant pathways for the dissemination of antibiotic resistance genes (ARGs). This study investigates the potential of wastewater-based epidemiology (WBE) as an early warning system for assessing the burden of AMR at the population level. In this comprehensive year-long study, effluent was collected weekly from three large hospitals, and treated and untreated wastewater were collected monthly from three associated community WWTPs. Metagenomic analysis revealed a significantly higher relative abundance and diversity of ARGs in hospital wastewater than in WWTPs. Notably, ARGs conferring resistance to clinically significant antibiotics such as β-lactams, aminoglycosides, sulfonamides, and tetracyclines were more prevalent in hospital effluents. Conversely, resistance genes associated with rifampicin and MLS (macrolides-lincosamide-streptogramin) were more commonly detected in the WWTPs, particularly in the treated effluent. Network analysis identified the potential bacterial hosts, which are the key carriers of these ARGs. The study further highlighted the variability in ARG removal efficiencies across the WWTPs, with none achieving complete elimination of ARGs or a significant reduction in bacterial diversity. Additionally, ARG profiles remained relatively consistent in hospital and community wastewater throughout the study, indicating a persistent release of a baseload of ARGs and pathogenic bacteria into surface waters, potentially polluting aquatic environments and entering the food chain. The study underscores the need for routine WBE surveillance, enhanced wastewater treatment strategies, and hospital-level source control measures to mitigate AMR dissemination into the environment. | 2025 | 39798461 |
| 7134 | 15 | 0.9764 | Elevated levels of antibiotic resistance in groundwater during treated wastewater irrigation associated with infiltration and accumulation of antibiotic residues. Treated wastewater irrigation (TWW) releases antibiotics and antibiotic resistance genes (ARGs) into the environment and might thus promote the dissemination of antibiotic resistance in groundwater (GW). We hypothesized that TWW irrigation increases ARG abundance in GW through two potential mechanisms: the contamination of GW with resistant bacteria and the accumulation of antibiotics in GW. To test this, the GW below a real-scale TWW-irrigated field was sampled for six months. Sampling took place before, during and after high-intensity TWW irrigation. Samples were analysed with 16S rRNA amplicon sequencing, qPCR of six ARGs and the class 1 integron-integrase gene intI1, while liquid chromatography tandem mass spectrometry was performed to detect antibiotic and pharmaceutical residues. Absolute abundance of 16S rRNA in GW decreased rather than increased during long-term irrigation. Also, the relative abundance of TWW-related bacteria did not increase in GW during long-term irrigation. In contrast, long-term TWW irrigation increased the relative abundance of sul1 and intI1 in the GW microbiome. Furthermore, GW contained elevated concentrations of sulfonamide antibiotics, especially sulfamethoxazole, to which sul1 confers resistance. Total sulfonamide concentrations in GW correlated with sul1 relative abundance. Consequently, TWW irrigation promoted sul1 and intI1 dissemination in the GW microbiome, most likely due to the accumulation of drug residues. | 2022 | 34555761 |
| 3072 | 16 | 0.9764 | Faecal microbiota and antibiotic resistance genes in migratory waterbirds with contrasting habitat use. Migratory birds may have a vital role in the spread of antimicrobial resistance across habitats and regions, but empirical data remain scarce. We investigated differences in the gut microbiome composition and the abundance of antibiotic resistance genes (ARGs) in faeces from four migratory waterbirds wintering in South-West Spain that differ in their habitat use. The white stork Ciconia ciconia and lesser black-backed gull Larus fuscus are omnivorous and opportunistic birds that use highly anthropogenic habitats such as landfills and urban areas. The greylag goose Anser anser and common crane Grus grus are herbivores and use more natural habitats. Fresh faeces from 15 individuals of each species were analysed to assess the composition of bacterial communities using 16S rRNA amplicon-targeted sequencing, and to quantify the abundance of the Class I integron integrase gene (intI1) as well as genes encoding resistance to sulfonamides (sul1), beta-lactams (bla(TEM), bla(KPC) and bla(NDM)), tetracyclines (tetW), fluoroquinolones (qnrS), and colistin (mcr-1) using qPCR. Bacterial communities in gull faeces were the richest and most diverse. Beta diversity analysis showed segregation in faecal communities between bird species, but those from storks and gulls were the most similar, these being the species that regularly feed in landfills. Potential bacterial pathogens identified in faeces differed significantly between bird species, with higher relative abundance in gulls. Faeces from birds that feed in landfills (stork and gull) contained a significantly higher abundance of ARGs (sul1, bla(TEM), and tetW). Genes conferring resistance to last resort antibiotics such as carbapenems (bla(KPC)) and colistin (mcr-1) were only observed in faeces from gulls. These results show that these bird species are reservoirs of antimicrobial resistant bacteria and suggest that waterbirds may disseminate antibiotic resistance across environments (e.g., from landfills to ricefields or water supplies), and thus constitute a risk for their further spread to wildlife and humans. | 2021 | 33872913 |
| 7171 | 17 | 0.9763 | Household waste-specific ambient air shows greater inhalable antimicrobial resistance risks in densely populated communities. Household waste is a hotspot of antibiotic resistance, which can be readily emitted to the ambient airborne inhalable particulate matters (PM(10)) during the day-long storage in communities. Nevertheless, whether these waste-specific inhalable antibiotic resistance genes (ARGs) are associated with pathogenic bacteria or pose hazards to local residents have yet to be explored. By high-throughput metagenomic sequencing and culture-based antibiotic resistance validation, we analyzed 108 airborne PM(10) and nearby environmental samples collected across different types of residential communities in Shanghai, the most populous city in China. Compared to the cold-dry period, the warm-humid season had significantly larger PM(10)-associated antibiotic resistomes in all types of residential communities (T-test, P < 0.001), most of airborne ARGs in which were estimatedly originated from disposed household waste (∼ 30 %). In addition, the airborne bacteria were assembled in a deterministic approach (iCAMP, P < 0.01), where the waste-specific bacteria taxa including Acinetobacter, Pseudomonas, Rhodococcus, and Kocuria had the predominant niches in the airborne microbial assemblages. Notably, these waste-sourced bacteria were also identified as the primary airborne hosts of ARGs encoding the aminoglycoside resistances. Among them, some antibiotic resistant human pathogens, such as Pseudomonas aeruginosa and Acinetobacter baumannii, not only exhibited higher ARG horizontal gene transfer (HGT) potential across the microbial assemblages, but also imposed direct infection risks on the local residents by 2 min inhalation exposure per day. When the daily exposure duration increased to 11 min, the infection-induced illness burden became unignorably high, especially in densely populated urban communities, being twofold greater than rural areas. | 2025 | 39862584 |
| 7332 | 18 | 0.9763 | Metagenomic Survey Reveals More Diverse and Abundant Antibiotic Resistance Genes in Municipal Wastewater Than Hospital Wastewater. Alongside antibiotic resistance, co-selection of antibiotics, biocides, and metal resistance is a growing concern. While hospital wastewater is considered a hotspot for antibiotic-resistant bacteria (ARB) and genes (ARGs), the scenario in India, one of the biggest consumers of antibiotics, remains poorly described. In this study, we used metagenomic sequencing to characterize ARGs and biocide/metal resistance genes (BMRGs) in four wastewater treatment plants (WWTPs) in Jaipur City of India. We observed a significantly lower richness and abundance of ARGs in the influent of a WWTP exclusively receiving hospital wastewater when compared to other three WWTPs involving municipal wastewater treatment. Several tetracycline and macrolide-lincosamide-streptogramin resistance genes were enriched in influents of these three municipal wastewater-related treatment plants, whereas hospital wastewater had a higher abundance of genes conferring resistance to disinfectant-related compounds such as synergize and wex-cide-128, reflecting the patterns of antibiotic/disinfectant use. Of note, in the wastewater system with more chemicals, there was a strong correlation between the numbers of ARGs and BMRGs potentially harbored by common hosts. Our study highlights significant influxes of ARGs from non-hospital sources in Jaipur City, and thus more attention should be paid on the emergence of ARGs in general communities. | 2021 | 34526976 |
| 7443 | 19 | 0.9763 | Wastewater pollution differently affects the antibiotic resistance gene pool and biofilm bacterial communities across streambed compartments. Wastewater discharges introduce antibiotic residues and antibiotic-resistant bacteria (ARB) into surface waters. Both inputs directly affect the streambed resistome, either by exerting a selective pressure that favour the proliferation of resistant phenotypes or by enriching the resident communities with wastewater-associated ARB. Here, we investigated the impact of raw and treated urban wastewater discharges on epilithic (growing on rocks) and epipsammic (growing on sandy substrata) streambed biofilms. The effects were assessed by comparing control and impact sites (i) on the composition of bacterial communities; (ii) on the abundance of twelve antibiotic resistance genes (ARGs) encoding resistance to β-lactams, fluoroquinolones, sulphonamides, tetracyclines, macrolides and vancomycin, as well as the class 1 integron-integrase gene (intI1); (iii) on the occurrence of wastewater-associated bacteria, including putative pathogens, and their potential linkage to target ARGs. We measured more pronounced effects of raw sewage than treated wastewater at the three studied levels. This effect was especially noticeable in epilithic biofilms, which showed a higher contribution of wastewater-associated bacteria and ARB than in epipsammic biofilms. Comparison of correlation coefficients obtained between the relative abundance of both target ARGs and operational taxonomic units classified as either potential pathogens or nonpathogens yielded significant higher correlations between the former category and genes intI1, sul1, sul2 and ermB. Altogether, these results indicate that wastewater-associated micro-organisms, including potential pathogens, contribute to maintain the streambed resistome and that epilithic biofilms appear as sensitive biosensors of the effect of wastewater pollution in surface waters. | 2017 | 28792642 |