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727600.9876Antibiotic 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
349810.9874Comparative study on the bacterial diversity and antibiotic resistance genes of urban landscape waters replenished by reclaimed water and surface water in Xi'an, China. Pathogenic bacteria and antibiotic resistance genes (ARGs) in urban landscape waters may pose a potential threat to human health. However, the investigation of their occurrence in the urban landscape waters replenished by reclaimed water (RW) and surface water (SW) is still insufficient. The water samples collected from six urban landscape waters replenished by RW or SW were used to analyze bacterial diversity using high-throughput sequencing of 16S rRNA gene and to detect 18 ARGs and 2 integron-integrase genes by means of quantitative PCR array. Results indicated that Proteobacteria was the dominant phylum in all six urban landscape waters. The bacterial species richness was lower in urban landscape waters replenished by RW than that by SW. Sulfonamide resistance genes (sulI and sulIII) were the major ARGs in these urban landscape waters. No significant difference in the relative abundance of sulfonamide resistance genes, tetracycline resistance genes, and most of beta-lactam resistance genes was observed between RW-replenished and SW-replenished urban landscape waters. By contrast, the relative abundance of bla(ampC) gene and qnrA gene in RW-replenished urban landscape waters was significantly higher than that in SW-replenished urban landscape waters (p < 0.05), which suggested that use of RW may increase the amount of specific ARGs to urban landscape waters. Interestingly, among six urban landscape waters, RW-replenished urban landscape waters had a relatively rich variety of ARGs (12-15 of 18 ARGs) but a low relative abundance of ARGs (458.90-1944.67 copies/16S × 10(6)). The RW replenishment was found to have a certain impact on the bacterial diversity and prevalence of ARGs in urban landscape waters, which provide new insight into the effect of RW replenishment on urban landscape waters.202133786766
713320.9873Prevalence 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
708830.9872Small-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
721540.9868High-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
733150.9867Metagenomics 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
708760.9867Antibiotic 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.202134226964
727770.9867Occurrence 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
716480.9867Anthropogenic 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
735190.9866Dynamics 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.202134673462
7267100.9866Antimicrobial 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
7779110.9866Metagenomic 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
7240120.9865Effects 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
7781130.9865Untreated 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
7081140.9865Seasonal 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.202032806354
7352150.9865Impacts of reclaimed water irrigation on soil antibiotic resistome in urban parks of Victoria, Australia. The effluents from wastewater treatment plants have been recognized as a significant environmental reservoir of antibiotics and antibiotic resistance genes (ARGs). Reclaimed water irrigation (RWI) is increasingly used as a practical solution for combating water scarcity in arid and semiarid regions, however, impacts of RWI on the patterns of ARGs and the soil bacterial community remain unclear. Here, we used high-throughput quantitative PCR and terminal restriction fragment length polymorphism techniques to compare the diversity, abundance and composition of a broad-spectrum of ARGs and total bacteria in 12 urban parks with and without RWI in Victoria, Australia. A total of 40 unique ARGs were detected across all park soils, with genes conferring resistance to β-lactam being the most prevalent ARG type. The total numbers and the fold changes of the detected ARGs were significantly increased by RWI, and marked shifts in ARG patterns were also observed in urban parks with RWI compared to those without RWI. The changes in ARG patterns were paralleled by a significant effect of RWI on the bacterial community structure and a co-occurrence pattern of the detected ARG types. There were significant and positive correlations between the fold changes of the integrase intI1 gene and two β-lactam resistance genes (KPC and IMP-2 groups), but no significant impacts of RWI on the abundances of intI1 and the transposase tnpA gene were found, indicating that RWI did not improve the potential for horizontal gene transfer of soil ARGs. Taken together, our findings suggested that irrigation of urban parks with reclaimed water could influence the abundance, diversity, and compositions of a wide variety of soil ARGs of clinical relevance. ONE-SENTENCE SUMMARY: Irrigation of urban parks with treated wastewater significantly increased the abundance and diversity of various antibiotic resistance genes, but did not significantly enhance their potential for horizontal gene transfer.201626736055
7306160.9865Impact of the particulate matter from wastewater discharge on the abundance of antibiotic resistance genes and facultative pathogenic bacteria in downstream river sediments. Wastewater treatment plants (WWTPs) are point sources for both, the release of antibiotic resistance genes (ARGs) and the discharge of antibiotics (ABs) into the environment. While it is well established that ARGs emission by WWTPs leads to an ARGs increase in receiving rivers, also the role of sub-inhibitory AB concentrations in this context is being discussed. However, the results obtained in this study suggest that, at environmental concentrations, ABs do not have an effect on resistance selection. Instead, we emphasize the significance of ARG transport and, in that respect, highlight the relevance of wastewater particles and associated microorganisms. We can show that ARGs (ermB, bla(TEM,)tetM, qnrS) as well as facultative pathogenic bacteria (FPB) (enterococci, Pseudomonas aeruginosa, Acinetobacter baumannii) inside the particulate fraction of WWTP effluent are very likely to remain in the riverbed of the receiving water due to sedimentation. Moreover, ARG and FPB abundances measured in the particulate fraction strongly correlated with the delta ARG and FPB abundances measured in the receiving river sediment (downstream compared to upstream) (R(2) = 0.93, p < 0.05). Apparently, the sheer amount of settleable ARGs and FPB from WWTP effluent is sufficient, to increase abundances in the receiving riverbed by 0.5 to 2 log units.201930308888
7327170.9864Exploring the microbiome, antibiotic resistance genes, mobile genetic element, and potential resistant pathogens in municipal wastewater treatment plants in Brazil. Wastewater treatment plants (WWTPs) have been widely investigated in Europe, Asia and North America regarding the occurrence and fate of antibiotic resistance (AR) elements, such as antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and antibiotic resistant bacteria and pathogens. However, monitoring data about AR elements in municipal WWTPs in Brazil are scarce. This study investigated the abundance of intI1, five ARGs (sul1, tetA, blaTEM, ermB and qnrB) and 16S rRNA in raw and treated wastewater of three WWTPs, using different sewage treatments named CAS (Conventional activated sludge), UASB/BTF (UASB followed by biological trickling filter) and MAS/UV (modified activated sludge with UV disinfection stage). Bacterial diversity and the presence of potentially pathogenic groups were also evaluated, and associations between genetic markers and the bacterial populations were presented. All WWTPs decreased the loads of genetic markers finally discharged to receiving water bodies and showed no evidence of being hotspots for antimicrobial resistance amplification in wastewater, since the abundances of intI1 and ARGs within the bacterial population were not increased in the treated effluents. UASB/BTF showed a similar performance to that of the CAS and MAS/UV, reinforcing the sanitary and environmental advantages of this biological treatment, widely applied for wastewater treatment in warm climate regions. Bacterial diversity and richness increased after treatments, and bacterial communities in wastewater samples differed due to catchment areas and treatment typologies. Potential pathogenic population underwent considerable decrease after the treatments; however, strong significant correlations with intI1 and ARGs revealed potential multidrug-resistant pathogenic bacteria (Aeromonas, Arcobacter, Enterobacter, Escherichia-Shigella, Stenotrophomonas and Streptococcus) in the treated effluents, although in reduced relative abundances. These are contributive results for understanding the fate of ARGs, MGEs and potential pathogenic bacteria after wastewater treatments, which might support actions to mitigate their release into Brazilian aquatic environments in the near future.202235724791
7143180.9864Simulated 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
3075190.9864Comparison 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