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713300.9862Prevalence 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.201728192677
721510.9861High-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.202540127809
778120.9860Untreated HWWs Emerged as Hotpots for ARGs. Hospital wastewaters (HWWs) are reported to be hotspots for antibiotics and antibiotic-resistant bacteria. However, limited information involves the impact of these effluents on dissemination of antibiotic-resistance genes (ARGs). In this study, therefore, seasonally collected HWWs were monitored for overall bacterial load and seven ARGs aadA, tetA, cmlA, sul1, qnrS, ermB and bla (CTX-M )by using quantitative polymerase chain reaction method. Overall bacterial 16S rRNA copy number was found to be the lowest in winter with 10(3 )copy number/mL, while the highest copy number, with 10(5 )copy number/mL, was observed in both summer and spring. All hospitals tested displayed similar seasonal ARG copy number profile of aadA > tetA > cmlA ≈ sul1 > ermB ≈ qnrS > bla (CTX-M). The results indicated that untreated HWWs were hotspots for ARGs and required attention before discharging into public sewer.202031965225
727630.9860Antibiotic 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.201829730567
708840.9860Small-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.202031561123
727750.9859Occurrence and persistence of carbapenemases genes in hospital and wastewater treatment plants and propagation in the receiving river. This study aims to investigate the prevalence of clinically relevant carbapenemases genes (bla(KPC), bla(NDM) and bla(OXA-48)) in water samples collected over one-year period from hospital (H), raw and treated wastewater of two wastewater treatment plants (WWTPs) as well as along the Zenne River (Belgium). The genes were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that absolute abundances were the highest in H waters. Although absolute abundances were significantly reduced in WWTP effluents, the relative abundance (normalized per 16S rRNA) was never lowered through wastewater treatment. Particularly, for the PAB the relative abundances were significantly higher in the effluents respect to the influents of both WWTPs for all the genes. The absolute abundances along the Zenne River increased from upstream to downstream, peaking after the release of WWTPs effluents, in both fractions. Our results demonstrated that bla(KPC), bla(NDM) and bla(OXA-48) are widely distributed in the Zenne as a consequence of chronic discharge from WWTPs. To conclude, the levels of carbapenemases genes are significantly lower than other genes conferring resistance to more widely used antibiotics (analyzed in previous studies carried out at the same sites), but could raise up to the levels of high prevalent resistance genes.201829960932
307760.9859The influence of urbanization and water reclamation plants on fecal indicator bacteria and antibiotic resistance in the Los Angeles River watershed: A case study with complementary monitoring methods. Urban land use and water reclamation plants (WRPs) can impact fecal indicator bacteria (FIB) and antimicrobial resistance (AMR) in coastal watersheds. However, there is a lack of studies exploring these effects on the US West Coast. Additionally, there is limited research using a complementary approach across culture-, qPCR-, and metagenomics-based techniques for characterizing environmental AMR. In this study, sixteen locations were sampled in the Los Angeles River, encompassing both upstream and downstream of three WRPs discharging into the river. Culture-dependent methods quantified Enterococcus, total coliforms, E. coli, and extended spectrum beta-lactamase-producing E. coli as a low-cost screening tool for AMR, while qPCR measured selected antibiotic resistance genes (ARGs): sul1, ermF, tetW, blaSHV, along with intI1 and 16S rRNA genes. Bacteroides HF183 and crAssphage markers were quantified via ddPCR. All samples underwent shotgun sequencing to investigate gene abundance and mobility and an overall risk score for AMR. Results reveal downstream sites contain ARGs at least two orders of magnitude greater than upstream locations. Developed areas had the highest ARG sequence abundances and the most ARG classes as indicated by metagenomic analysis. WRP effluent exhibited elevated ARGs and co-location of ARGs, mobile genetic elements, and pathogens. A culture-based assessment of AR in E. coli and Pseudomonas aeruginosa revealed increased resistance ratios for most antibiotics from upstream to downstream a WRP discharge point. This study highlights the impacts of land use and WRPs on ARGs and FIB, offering a multi-pronged analysis of AMR.202439566612
726770.9859Antimicrobial resistance transmission in the environmental settings through traditional and UV-enabled advanced wastewater treatment plants: a metagenomic insight. BACKGROUND: Municipal wastewater treatment plants (WWTPs) are pivotal reservoirs for antibiotic-resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). Selective pressures from antibiotic residues, co-selection by heavy metals, and conducive environments sustain ARGs, fostering the emergence of ARB. While advancements in WWTP technology have enhanced the removal of inorganic and organic pollutants, assessing ARG and ARB content in treated water remains a gap. This metagenomic study meticulously examines the filtration efficiency of two distinct WWTPs-conventional (WWTPC) and advanced (WWTPA), operating on the same influent characteristics and located at Aligarh, India. RESULTS: The dominance of Proteobacteria or Pseudomonadota, characterized the samples from both WWTPs and carried most ARGs. Acinetobacter johnsonii, a prevailing species, exhibited a diminishing trend with wastewater treatment, yet its persistence and association with antibiotic resistance underscore its adaptive resilience. The total ARG count was reduced in effluents, from 58 ARGs, representing 14 distinct classes of antibiotics in the influent to 46 and 21 in the effluents of WWTPC and WWTPA respectively. However, an overall surge in abundance, particularly influenced by genes such as qacL, bla(OXA-900), and rsmA was observed. Numerous clinically significant ARGs, including those against aminoglycosides (AAC(6')-Ib9, APH(3'')-Ib, APH(6)-Id), macrolides (EreD, mphE, mphF, mphG, mphN, msrE), lincosamide (lnuG), sulfonamides (sul1, sul2), and beta-lactamases (bla(NDM-1)), persisted across both conventional and advanced treatment processes. The prevalence of mobile genetic elements and virulence factors in the effluents possess a high risk for ARG dissemination. CONCLUSIONS: Advanced technologies are essential for effective ARG and ARB removal. A multidisciplinary approach focused on investigating the intricate association between ARGs, microbiome dynamics, MGEs, and VFs is required to identify robust indicators for filtration efficacy, contributing to optimized WWTP operations and combating ARG proliferation across sectors.202540050994
777980.9857Metagenomic and Resistome Analysis of a Full-Scale Municipal Wastewater Treatment Plant in Singapore Containing Membrane Bioreactors. Reclaimed water provides a water supply alternative to address problems of scarcity in urbanized cities with high living densities and limited natural water resources. In this study, wastewater metagenomes from 6 stages of a wastewater treatment plant (WWTP) integrating conventional and membrane bioreactor (MBR) treatment were evaluated for diversity of antibiotic resistance genes (ARGs) and bacteria, and relative abundance of class 1 integron integrases (intl1). ARGs confering resistance to 12 classes of antibiotics (ARG types) persisted through the treatment stages, which included genes that confer resistance to aminoglycoside [aadA, aph(6)-I, aph(3')-I, aac(6')-I, aac(6')-II, ant(2″)-I], beta-lactams [class A, class C, class D beta-lactamases (bla (OXA))], chloramphenicol (acetyltransferase, exporters, floR, cmIA), fosmidomycin (rosAB), macrolide-lincosamide-streptogramin (macAB, ereA, ermFB), multidrug resistance (subunits of transporters), polymyxin (arnA), quinolone (qnrS), rifamycin (arr), sulfonamide (sul1, sul2), and tetracycline (tetM, tetG, tetE, tet36, tet39, tetR, tet43, tetQ, tetX). Although the ARG subtypes in sludge and MBR effluents reduced in diversity relative to the influent, clinically relevant beta lactamases (i.e., bla (KPC), bla (OXA)) were detected, casting light on other potential point sources of ARG dissemination within the wastewater treatment process. To gain a deeper insight into the types of bacteria that may survive the MBR removal process, genome bins were recovered from metagenomic data of MBR effluents. A total of 101 close to complete draft genomes were assembled and annotated to reveal a variety of bacteria bearing metal resistance genes and ARGs in the MBR effluent. Three bins in particular were affiliated to Mycobacterium smegmatis, Acinetobacter Iwoffii, and Flavobacterium psychrophila, and carried aquired ARGs aac(2')-Ib, bla (OXA-278), and tet36 respectively. In terms of indicator organisms, cumulative log removal values (LRV) of Escherichia coli, Enterococci, and P. aeruginosa from influent to conventional treated effluent was lower (0-2.4), compared to MBR effluent (5.3-7.4). We conclude that MBR is an effective treatment method for reducing fecal indicators and ARGs; however, incomplete removal of P. aeruginosa in MBR treated effluents (<8 MPN/100 mL) and the presence of ARGs and intl1 underscores the need to establish if further treatment should be applied prior to reuse.201930833934
307490.9857Metagenomic 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.202438043772
3075100.9857Comparison 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.202235973543
7164110.9856Anthropogenic 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.202540858019
7143120.9856Simulated discharge of treated landfill leachates reveals a fueled development of antibiotic resistance in receiving tidal river. Around 350 million tons of solid waste is disposed of in landfills every year globally, with millions of cubic meters of landfill leachates released into neighboring environment. However, to date, little is known about the variations of antimicrobial resistance (AMR) in on-site leachate treatment systems and its development in leachate-receiving water environment. Here, we quantified 7 subtypes of antibiotic resistance genes (ARGs), 3 types of culturable antibiotic resistant bacteria (ARB) and 6 subtypes of mobile genetic elements (MGEs) in the effluents from a combined leachate treatment process, including biological treatment (MBR), physical separation (UF), ultraviolet (UV) disinfection and advanced oxidation process (AOP). The contents of ARGs, ARB and MGEs were generally enriched by the MBR, but then decreased significantly along with the tertiary treatment process. However, in the effluent-receiving water samples, the abundance of dominant ARGs (i.e. ermB, sul1, bla(TEM)) increased by 1.5 orders of magnitude within 96 h, alongside a general increase of MGEs (~10.0 log(10)(copies/mL) and total ARB (~1100 CFU/mL). Structural correlation analyses reveal that target ARGs were closely associated with MGEs, particularly in effluent-receiving samples (Procrustes test; M(2) = 0.49, R = 0.71, P = 0.001); and occurrences of ARB were majorly affected by ARG's distribution and environmental conditions (e.g. nitrogen speciation) in effluent and recipient groups, respectively. This study indicates that current treatment technologies and operation protocols are not feasible in countering the development of AMR in effluent-receiving water environment, particularly in tidal rivers that are capable of retaining contaminants for a long residence time.201829501852
3301130.9855Hospital Wastewater Releases of Carbapenem-Resistance Pathogens and Genes in Urban India. Increasing antibiotic resistant hospital-acquired infections and limited new antibiotic discovery are jeopardizing human health at global scales, although how hospitals themselves fuel antimicrobial resistance (AMR) in the wider environment is largely unknown. Antibiotic resistance (AR) in hospitals in countries such as India is potentially problematic because of high antibiotic use, overcrowding, and inadequate wastewater containment. Here we quantified fecal coliforms (FC), carbapenem-resistant Enterobacteriaceae (CRE), bla(NDM-1), and selected extended-spectrum β-lactam (ESBL) resistant bacteria and genes in 12 hospital wastewater outfalls and five background sewer drains across New Delhi over two seasons. Hospital wastewaters had up to 9 orders of magnitude greater concentrations of CRE bacteria and bla(NDM-1) than local sewers (depending on the hospital), implying hospitals contribute high concentrations of AR relative to community sources in Delhi, especially during the winter. Significant correlations were found between FC levels (a fecal indictor), and CRE (r = 0.924; p = 0.005), bla(NDM-1) (r = 0.934, p = 0.009), and ESBL-resistant bacteria (r = 0.913, p = 0.010) levels across hospital wastewaters, respectively, implying that elevated CRE and bla(NDM-1) are of patient origin. However, of greater importance to global health, microbial culturing found 18 to 41% of wastewater CRE isolates (n = 1447) were on the WHO "critical pathogen" list in urgent need of new antibiotics, and 55% of CRE isolates from larger hospitals carried at least one bla(NDM-1) gene. Wastewater releases from New Delhi hospitals may pose a greater AR exposure risk to residents than believed, implying in-hospital antibiotic use must be better controlled and more effective waste treatment is needed for hospital wastewaters.201728949542
7271140.9855Identification of critical control points for antibiotic resistance discharge in sewers. Disrupting the spread of clinically relevant antibiotic resistance genes (ARGs) is one of the key components for the success of the One Health strategy. While waste water treatment plants (WWTPs) represent a final control point for daily discharges of antibiotic resistance genes (ARGs) to the aquatic environment, a decentralized upstream monitoring of wastewater feeds of selected urban drainage areas for bla(CTX-M32), bla(CTX-M15), bla(OXA48), bla(CMY-2), mecA, bla(NDM-1), bla(KPC3), vanA, and mcr-1 representing clinically relevant ARGs has been performed. Besides hospitals, also retirement homes were found to be responsible for high levels of ARG discharges compared to housing area sewer systems. The monitoring combines qPCR-based quantifications, flow volume-based analyses, and multiple antibiotic resistance analyses of isolates. As result of the study, local actions at identified critical control points could help to prevent contaminations of larger volumes of wastewaters. This strategy will support a more cost-effective treatment compared to central actions at WWTPs, only. A polluter-pays principle should be applied by this monitoring strategy.202235051461
7331150.9855Metagenomics 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
7755160.9854Anthropogenic impacts on sulfonamide residues and sulfonamide resistant bacteria and genes in Larut and Sangga Besar River, Perak. The environmental reservoirs of sulfonamide (SA) resistome are still poorly understood. We investigated the potential sources and reservoir of SA resistance (SR) in Larut River and Sangga Besar River by measuring the SA residues, sulfamethoxazole resistant (SMX(r)) in bacteria and their resistance genes (SRGs). The SA residues measured ranged from lower than quantification limits (LOQ) to 33.13 ng L(-1) with sulfadiazine (SDZ), sulfadimethoxine (SDM) and SMX as most detected. Hospital wastewater effluent was detected with the highest SA residues concentration followed by the slaughterhouse and zoo wastewater effluents. The wastewater effluents also harbored the highest abundance of SMX(r)-bacteria (10(7) CFU mL(-1)) and SRGs (10(-1)/16S copies mL(-1)). Pearson correlation showed only positive correlation between the PO(4) and SMX(r)-bacteria. In conclusion, wastewater effluents from the zoo, hospital and slaughterhouse could serve as important sources of SA residues that could lead to the consequent emergence of SMX(r)-bacteria and SRGs in the river.201931726563
7240170.9854Effects of industrial effluents containing moderate levels of antibiotic mixtures on the abundance of antibiotic resistance genes and bacterial community composition in exposed creek sediments. Environmental discharges of very high (mg/L) antibiotic levels from pharmaceutical production contributed to the selection, spread and persistence of antibiotic resistance. However, the effects of less antibiotic-polluted effluents (μg/L) from drug-formulation on exposed aquatic microbial communities are still scarce. Here we analyzed formulation effluents and sediments from the receiving creek collected at the discharge site (DW0), upstream (UP) and 3000 m downstream of discharge (DW3000) during winter and summer season. Chemical analyses indicated the largest amounts of trimethoprim (up to 5.08 mg/kg) and azithromycin (up to 0.39 mg/kg) at DW0, but sulfonamides accumulated at DW3000 (total up to 1.17 mg/kg). Quantitative PCR revealed significantly increased relative abundance of various antibiotic resistance genes (ARGs) against β-lactams, macrolides, sulfonamides, trimethoprim and tetracyclines in sediments from DW0, despite relatively high background levels of some ARGs already at UP site. However, only sulfonamide (sul2) and macrolide ARG subtypes (mphG and msrE) were still elevated at DW3000 compared to UP. Sequencing of 16S rRNA genes revealed pronounced changes in the sediment bacterial community composition from both DW sites compared to UP site, regardless of the season. Numerous taxa with increased relative abundance at DW0 decreased to background levels at DW3000, suggesting die-off or lack of transport of effluent-originating bacteria. In contrast, various taxa that were more abundant in sediments than in effluents increased in relative abundance at DW3000 but not at DW0, possibly due to selection imposed by high sulfonamide levels. Network analysis revealed strong correlation between some clinically relevant ARGs (e.g. bla(GES), bla(OXA), ermB, tet39, sul2) and taxa with elevated abundance at DW sites, and known to harbour opportunistic pathogens, such as Acinetobacter, Arcobacter, Aeromonas and Shewanella. Our results demonstrate the necessity for improved management of pharmaceutical and rural waste disposal for mitigating the increasing problems with antibiotic resistance.202031855637
7344180.9854Antibiotic resistance genes in municipal wastewater treatment systems and receiving waters in Arctic Canada. Domestic wastewater discharges may adversely impact arctic ecosystems and local indigenous people, who rely on being able to hunt and harvest food from their local environment. Therefore, there is a need to develop efficient wastewater treatment plants (WWTPs), which can be operated in remote communities under extreme climatic conditions. WWTPs have been identified as reservoirs of antibiotic resistance genes (ARGs). The objective of this work was to quantify the presence of nine different ARG markers (int1, sul1, sul2, tet(O), erm(B), mecA, bla(CTX-M), bla(TEM), and qnr(S)) in two passive systems (waste stabilization ponds [WSPs]) and one mechanical filtration plant operating in two smaller and one large community, respectively, in Nunavut, Canada. Measurement of water quality parameters (carbonaceous oxygen demand, ammonia, total suspended solids, Escherichia coli and total coliforms) showed that the WWTPs provided only primary treatment. Low levels of the ARGs (2logcopies/mL) were observed in the effluent, demonstrating that bacteria residing in three northern WWTPs harbour ARGs conferring resistance to multiple clinically-relevant classes of antibiotics. Our results indicate that long-term storage in WSPs benefitted removal of organic material and some ARGs. However, one WSP system showed evidence of the enrichment of sul1, sul2, mecA, tet(O) and qnr(S). Further research is needed to fully understand if these ARG releases pose a risk to human health, especially in the context of traditional hunting and fishing activities.201728482456
5338190.9853Characterisation of microbial communities and quantification of antibiotic resistance genes in Italian wastewater treatment plants using 16S rRNA sequencing and digital PCR. The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in humans, animals and environment is a growing threat to public health. Wastewater treatment plants (WWTPs) are crucial in mitigating the risk of environmental contamination by effectively removing contaminants before discharge. However, the persistence of ARB and ARGs even after treatment is a challenge for the management of water system. To comprehensively assess antimicrobial resistance dynamics, we conducted a one-year monitoring study in three WWTPs in central Italy, both influents and effluents. We used seasonal sampling to analyze microbial communities by 16S rRNA, as well as to determine the prevalence and behaviour of major ARGs (sul1, tetA, bla(TEM), bla(OXA-48), bla(CTX-M-1 group), bla(KPC)) and the class 1 Integron (int1). Predominant genera included in order: Arcobacter, Acinetobacter, Flavobacterium, Pseudarcobacter, Bacteroides, Aeromonas, Trichococcus, Cloacibacterium, Pseudomonas and Streptococcus. A higher diversity of bacterial communities was observed in the effluents compared to the influents. Within these communities, we also identified bacteria that may be associated with antibiotic resistance and pose a significant threat to human health. The mean concentrations (in gene copies per liter, gc/L) of ARGs and int1 in untreated wastewater (absolute abundance) were as follows: sul1 (4.1 × 10(9)), tetA (5.2 × 10(8)), bla(TEM) (1.1 × 10(8)), bla(OXA-48) (2.1 × 10(7)), bla(CTX-M-1 group) (1.1 × 10(7)), bla(KPC) (9.4 × 10(5)), and int1 (5.5 × 10(9)). The mean values in treated effluents showed reductions ranging from one to three log. However, after normalizing to the 16S rRNA gene (relative abundance), it was observed that in 37.5 % (42/112) of measurements, the relative abundance of ARGs increased in effluents compared to influents. Furthermore, correlations were identified between ARGs and bacterial genera including priority pathogens. This study improves our understanding of the dynamics of ARGs and provides insights to develop more effective strategies to reduce their spread, protecting public health and preserving the future efficacy of antibiotics.202438750766