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735800.9821Global dispersal and potential sources of antibiotic resistance genes in atmospheric remote depositions. Antibiotic resistance has become a major Global Health concern and a better understanding on the global spread mechanisms of antibiotic resistant bacteria (ARB) and intercontinental ARB exchange is needed. We measured atmospheric depositions of antibiotic resistance genes (ARGs) by quantitative (q)PCR in rain/snow collected fortnightly along 4 y. at a remote high mountain LTER (Long-Term Ecological Research) site located above the atmospheric boundary layer (free troposphere). Bacterial composition was characterized by 16S rRNA gene sequencing, and air mass provenances were determined by modelled back trajectories and rain/snow chemical composition. We hypothesize that the free troposphere may act as permanent reservoir and vector for ARB and ARGs global dispersal. We aimed to i) determine whether ARGs are long-range intercontinental and persistently dispersed through aerosols, ii) assess ARGs long-term atmospheric deposition dynamics in a remote high mountain area, and iii) unveil potential diffuse ARGs pollution sources. We showed that the ARGs sul1 (resistance to sulfonamides), tetO (resistance to tetracyclines), and intI1 (a proxy for horizontal gene transfer and anthropogenic pollution) were long-range and persistently dispersed in free troposphere aerosols. Major depositions of tetracyclines resistance matched with intensification of African dust outbreaks. Potential ARB mostly traced their origin back into agricultural soils. Our study unveils that air masses pathways are shaping ARGs intercontinental dispersal and global spread of antibiotic resistances, with potential predictability for interannual variability and remote deposition rates. Because climate regulates aerosolization and long-range air masses movement patterns, we call for a more careful evaluation of the connections between land use, climate change and ARB long-range intercontinental dispersal.202235016024
713310.9821Prevalence 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
638020.9818Seasonal dynamics of anammox bacteria in estuarial sediment of the Mai Po Nature Reserve revealed by analyzing the 16S rRNA and hydrazine oxidoreductase (hzo) genes. The community and population dynamics of anammox bacteria in summer (wet) and winter (dry) seasons in estuarial mudflat sediment of the Mai Po Nature Reserve were investigated by 16S rRNA and hydrazine oxidoreductase (hzo) genes. 16S rRNA phylogenetic diversity showed that sequences related to 'Kuenenia' anammox bacteria were presented in summer but not winter while 'Scalindua' anammox bacteria occurred in both seasons and could be divided into six different clusters. Compared to the 16S rRNA genes, the hzo genes revealed a relatively uniform seasonal diversity, with sequences relating to 'Scalindua', 'Anammoxoglobus', and planctomycete KSU-1 found in both seasons. The seasonal specific bacterial groups and diversity based on the 16S rRNA and hzo genes indicated strong seasonal community structures in estuary sediment of this site. Furthermore, the higher abundance of hzo genes in summer than winter indicates clear seasonal population dynamics. Combining the physicochemical characteristics of estuary sediment in the two seasons and their correlations with anammox bacteria community structure, we proposed the strong seasonal dynamics in estuary sediment of Mai Po to be due to the anthropogenic and terrestrial inputs, especially in summer, which brings in freshwater anammox bacteria, such as 'Kuenenia', interacting with the coastal marine anammox bacteria 'Scalindua'.201121487198
699130.9818Distribution and drivers of antibiotic resistance genes in brackish water aquaculture sediment. Brackish water aquaculture has brought numerous economic benefits, whereas anthropogenic activities in aquaculture may cause the dissemination of antibiotic resistance genes (ARGs) in brackish water sediments. The intricate relationships between environmental factors and microbial communities as well as their role in ARGs dissemination in brackish water aquaculture remain unclear. This study applied PCR and 16S sequencing to identify the variations in ARGs, class 1 integron gene (intI1) and microbial communities in brackish water aquaculture sediment. The distribution of ARGs in brackish water aquaculture sediment was similar to that in freshwater aquaculture, and the sulfonamide resistance gene sul1 was the indicator of ARGs. Proteobacteria and Firmicutes were the dominant phyla, and Paenisporosarcina (p_ Firmicutes) was the dominant genus. The results of correlation, network and redundancy analysis indicated that the microbial community in the brackish water aquaculture sediment was function-driven. The neutral model and variation partitioning analysis were used to verify the ecological processes of the bacterial community. The normalized stochasticity ratio showed that pond bacteria community was dominated by determinacy, which was affected by aquaculture activities. The total nitrogen and organic matter influenced the abundance of ARGs, while Proteobacteria and Thiobacillus (p_Proteobacteria) were the key antibiotic-resistant hosts. Our study provides insight into the prevalence of ARGs in brackish water aquaculture sediments, and indicates that brackish water aquaculture is a reservoir of ARGs.202336436623
307640.9813Antimicrobial resistance genes (ARGs) in sea surface aerosols over the Atlantic Ocean. The large-scale abundance and distribution of antibiotic resistance genes (ARGs) within the atmosphere remains poorly documented, particularly over oceans. This study explores bacterial loads, diversity, and associated antimicrobial resistance genes in aerosols over the North Atlantic Ocean. Aerosol samples were collected from a ship during a cruise from Brest (France) to Woods Hole (USA) for 24-h periods using a mast-mounted system, with additional one-hour spot samples taken daily and nightly using high-flow rates samplers. The airborne concentrations of bacteria along with 21 ARG subtypes as indicators of key resistance families were monitored using qPCR. These were related to the bacterial diversity obtained from same samples through ribosomal gene amplicon sequencing, and to the geographical origin of the air masses estimated using atmospheric dynamics models. Total ARG concentrations ranged from background concentrations of a few copies to >10(5) copies/m(3) of air. Near coasts, macrolide and tetracycline resistance genes were dominant (up to 93 % and 38 % of the total ARG monitored here, respectively). While sulfonamide resistance genes were also detected further offshore, those related to transposases and β-lactamases were detected only sporadically. The multiple observed correlations between the aforementioned gene concentrations in the air and potential soil-derived microorganisms may be indicative of continental inputs. Conversely, the prevalence of quinolone resistance (qepA) in the air over the open ocean points toward a contribution from marine surfaces, supported by associations between several ARGs and marine microorganisms including cyanobacteria. These may thus act as environmental reservoirs of ARGs, and sources for further environmental spread notably by air means.202541106010
350050.9813Shifts in bacterial communities and antibiotic resistance genes in surface water and gut microbiota of guppies (Poecilia reticulata) in the upper Rio Uberabinha, Brazil. Anthropogenic activities especially water pollution can affect the diversity and composition of microbial communities and promote the spread of antibiotic resistance genes (ARGs). In this study, water samples and guppies (Poecilia reticulata) were sampled from six sampling sites along the Uberabinha River in southeastern Brazil, both microbial communities and ARGs of surface waters and intestinal microbiota of guppies (Poecilia reticulata) were detected. According to the results of 16S rRNA amplicon sequencing, Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria were dominant phyla in both water and intestinal microbiota, but the abundance of putative pathogens was higher at heavily polluted sites. Up to 83% of bacteria in intestinal microbiota originated from water microbiota; this proportion was relatively higher in less polluted compared to polluted environments. ARGs providing resistance of tetracyclines and quinolones were dominant in both water and gut microbiota. The relative abundances of class I integrons and ARGs were as high as 1.74 × 10(-1)/16S rRNA copies and 3.61 × 10(-1)/16S rRNA copies, respectively, at heavily polluted sites. Correlation analysis suggests that integrons and bacteria play key roles in explaining the widespread occurrence of ARGs in the surface, but not in intestinal microbiota. We could rule out the class I integrons a potential intermediary bridge for ARGs between both types of microbiomes. Our results highlight the tight link in microbial communities and ARGs between ambient microbiota of stream ecosystems and intestinal microbiota of fish. Our study could have far-reaching consequences for fisheries and consumer safety and calls for investigations of gut microbiota of target species of both commercial fisheries and recreational (hobby) angling.202133497859
307360.9813A 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.202134328962
735770.9812Metagenomic surveys show a widespread diffusion of antibiotic resistance genes in a transect from urbanized to marine protected area. Ports are hot spots of pollution; they receive pollution from land-based sources, marine traffic and port infrastructures. Marine ecosystems of nearby areas can be strongly affected by pollution from port-related activities. Here, we investigated the microbiomes present in sea floor sediments along a transect from the harbour of Livorno (Central Italy) to a nearby marine protected area. Results of 16S rRNA amplicon sequencing and metagenome assembled genomes (MAGs) analyses indicated the presence of different trends of specific bacterial groups (e.g. phyla NB1-j, Acidobacteriota and Desulfobulbales) along the transect, correlating with the measured pollution levels. Human pathogenic bacteria and antibiotic resistance genes (ARGs) were also found. These results demonstrate a pervasive impact of human port activities and highlight the importance of microbiological surveillance of marine sediments, which may constitute a reservoir of ARGs and pathogenic bacteria.202539908950
349880.9812Comparative 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
527990.9811Occurrence of integrons and antibiotic resistance genes in cryoconite and ice of Svalbard, Greenland, and the Caucasus glaciers. The prevalence of integrons and antibiotic resistance genes (ARGs) is a serious threat for public health in the new millennium. Although commonly detected in sites affected by strong anthropogenic pressure, in remote areas their occurrence, dissemination, and transfer to other ecosystems is poorly recognized. Remote sites are considered as a benchmark for human-induced contamination on Earth. For years glaciers were considered pristine, now they are regarded as reservoirs of contaminants, thus studies on contamination of glaciers, which may be released to other ecosystems, are highly needed. Therefore, in this study we evaluated the occurrence and frequency of clinically relevant ARGs and resistance integrons in the genomes of culturable bacteria and class 1 integron-integrase gene copy number in the metagenome of cryoconite, ice and supraglacial gravel collected on two Arctic (South-West Greenland and Svalbard) and two High Mountain (the Caucasus) glaciers. Altogether, 36 strains with intI1 integron-integrase gene were isolated. Presence of class 1 integron-integrase gene was also recorded in metagenomic DNA from all sampling localities. The mean values of relative abundance of intI1 gene varied among samples and ranged from 0.7% in cryoconite from Adishi Glacier (the Caucasus) to 16.3% in cryoconite from Greenland. Moreover, antibiotic-resistant strains were isolated from all regions. Genes conferring resistance to β-lactams (bla(SHV), bla(TEM), bla(OXA), bla(CMY)), fluoroquinolones (qepA, qnrC), and chloramphenicol (cat, cmr) were detected in the genomes of bacterial isolates.202032059297
3072100.9811Faecal 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.202133872913
3079110.9810Quantification of antibiotic resistance genes (ARGs) in clouds at a mountain site (puy de Dôme, central France). Antibiotic resistance in bacteria is becoming a major sanitary concern worldwide. The extensive use of large quantities of antibiotics to sustain human activity has led to the rapid acquisition and maintenance of antibiotic resistant genes (ARGs) in bacteria and to their spread into the environment. Eventually, these can be disseminated over long distances by atmospheric transport. Here, we assessed the presence of ARGs in clouds as an indicator of long-distance travel potential of antibiotic resistance in the atmosphere. We hypothesized that a variety of ARGs can reach the altitude of clouds mainly located within the free troposphere. Once incorporated in the atmosphere, they are efficiently transported and their respective concentrations should differ depending on the sources and the geographical origin of the air masses. We deployed high-flow rate impingers and collected twelve clouds between September 2019 and October 2021 at the meteorological station of the puy de Dôme summit (1465 m a.s.l., France). Total airborne bacteria concentration was assessed by flow cytometry, and ARGs subtypes of the main families of antibiotic resistance (quinolone, sulfonamide, tetracycline; glycopeptide, aminoglycoside, β-lactamase, macrolide) including one mobile genetic element (transposase) were quantified by qPCR. Our results indicate the presence of 29 different ARGs' subtypes at concentrations ranging from 1.01 × 10(3) to 1.61 × 10(4) copies m(-3) of air. Clear distinctions could be observed between clouds in air masses transported over marine areas (Atlantic Ocean) and clouds influenced by continental surfaces. Specifically, quinolones (mostly qepA) resistance genes were prevalent in marine clouds (54 % of the total ARGs on average), whereas higher contributions of sulfonamide, tetracycline; glycopeptide, β-lactamase and macrolide were found in continental clouds. This study constitutes the first evidence for the presence of microbial ARGs in clouds at concentrations comparable to other natural environments. This highlights the atmosphere as routes for the dissemination of ARGs at large scale.202336587700
3080120.9810Antibiotic-resistant bacteria in the Bang Yai Canal and Phuket Bay in Phuket Province, Thailand. Antimicrobial resistance (AMR) represents a critical public health challenge, with surface waters serving as reservoirs for antibiotic-resistant bacteria (ARB). Among these, gram-negative enteric bacteria (GNEB) are recognized as major carriers of resistance genes and frequent causes of human infections. As a major tourism destination in Thailand, Phuket Province is likely to face increasing AMR-related issues. This study investigates water quality and the prevalence of ARB in the Bang Yai Canal, a key urban waterway in Phuket, and its transition into Phuket Bay. Water samples were collected from nine stations during the dry and rainy seasons of 2024. Total heterotrophic bacterial counts and GNEB resistant to amoxicillin, tetracycline, norfloxacin, and meropenem were examined in relation to water quality parameters. Results revealed significant spatial variation, with urban areas contributing substantially to ARB prevalence. Amoxicillin-resistant bacteria were the most prevalent, particularly among GNEB, while meropenem-resistant bacteria were consistently detected at most stations despite their low abundance. Seasonal variations indicated higher bacterial abundance upstream during the dry season and downstream during the rainy season, potentially driven by tourism and runoff dynamics. The coastal station exhibited a notably high proportion of antibiotic-resistant marine heterotrophic bacteria. Redundancy analysis identified turbidity and dissolved oxygen as significant factors influencing bacterial counts. Cluster analysis grouped stations based on water quality, with upstream and coastal sites exhibiting distinct profiles. This study underscores the critical role of urban activities in ARB dissemination and highlights the environmental and public health implications of ARB in coastal ecosystems, necessitating targeted mitigation and monitoring strategies.202540976823
7134130.9809Elevated 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.202234555761
3483140.9808Abundance and diversity of antibiotic resistance genes and bacterial communities in the western Pacific and Southern Oceans. This study investigated the abundance and diversity of antibiotic resistance genes (ARGs) and the composition of bacterial communities along a transect covering the western Pacific Ocean (36°N) to the Southern Ocean (74°S) using the Korean icebreaker R/V Araon (total cruise distance: 14,942 km). The relative abundances of ARGs and bacteria were assessed with quantitative PCR and next generation sequencing, respectively. The absolute abundance of ARGs was 3.0 × 10(6) ± 1.6 × 10(6) copies/mL in the western Pacific Ocean, with the highest value (7.8 × 10(6) copies/mL) recorded at a station in the Tasman Sea (37°S). The absolute abundance of ARGs in the Southern Ocean was 1.8-fold lower than that in the western Pacific Ocean, and slightly increased (0.7-fold) toward Terra Nova Bay in Antarctica, possibly resulting from natural terrestrial sources or human activity. β-Lactam and tetracycline resistance genes were dominant in all samples (88-99%), indicating that they are likely the key ARGs in the ocean. Correlation and network analysis showed that Bdellovibrionota, Bacteroidetes, Cyanobacteria, Margulisbacteria, and Proteobacteria were positively correlated with ARGs, suggesting that these bacteria are the most likely ARG carriers. This study highlights the latitudinal profile of ARG distribution in the open ocean system and provides insights that will help in monitoring emerging pollutants on a global scale.202235085628
3543150.9806Precipitation 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.201829754026
3542160.9806Fecal 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.202133445049
7280170.9806Microbial communities of biofilms developed in a chlorinated drinking water distribution system: A field study of antibiotic resistance and biodiversity. Antibiotic resistance and biodiversity were investigated in microbial communities attached to inner surfaces of water supply fittings in a chlorinated drinking water distribution system (DWDS) supplied by two independent water treatment plants (WTPs) drawing the same source water. The investigation of the effect of the season, the applied water treatment technology, and type, material, and age of water supply fittings on both antibiotic resistance and biodiversity in biofilms involved collection of tubercles during summer and winter seasons throughout the DWDS. A total of 16 samples were collected (8 per season) from areas supplied by two independent WTPs. Culturable aerobic antibiotic resistant bacteria (ARB) proved more prevalent in summer. Various antibiotic resistance genes (ARGs) were detected, confirming the role of biofilms as ARGs reservoirs, but the abundances of quantified genes (sulI, ermB, qacEΔ1, intI1) were low (a range of 202133610999
6835180.9805Metagenomic profiling of antibiotic resistance genes and their associations with the bacterial community along the Kanda River, an urban river in Japan. Antibiotic resistance genes (ARGs) present in urban rivers have the potential to disseminate antibiotic-resistant bacteria into other environments, posing significant threats to both ecological and public health. Although metagenomic analyses have been widely employed to detect ARGs in rivers, our understanding of their dynamics across different seasons in diverse watersheds remains limited. In this study, we performed a comprehensive genomic analysis of the Kanda River in Japan at 11 sites from upstream to estuary throughout the year to assess the spread of ARGs and their associations with bacterial communities. Analysis of 110 water samples using the 16S rRNA gene revealed variations in bacterial composition corresponding to seasonal changes in environmental parameters along the river. Shotgun metagenomics-based profiling of ARGs in 44 water samples indicated higher ARG abundance downstream, particularly during the summer. Weighted gene co-expression network analysis (WGCNA) linking bacterial lineages and ARGs revealed that 12 ARG subtypes co-occurred with 128 amplicon sequence variants (ASVs). WGCNA suggested potential hosts for ErmB, ErmF, ErmG, tetQ, tet (W/N/W), aadA2, and adeF, including gut-associated bacteria (e.g., Prevotella, Bacteroides, Arcobacter) and indigenous aquatic microbes (e.g., Limnohabitans and C39). In addition, Pseudarcobacter (a later synonym of Arcobater) was identified as a host for adeF, which was also confirmed by single cell genomics. This study shows that ARG distribution in urban rivers is affected by seasonal and geographical factors and demonstrates the importance of monitoring rivers using multiple types of genome sequencing, including 16S rRNA gene sequencing, metagenomics, and single cell genomics.202539488451
7350190.9805The vertical distribution of tetA and intI1 in a deep lake is rather due to sedimentation than to resuspension. Lakes are exposed to anthropogenic pollution including the release of allochthonous bacteria into their waters. Antibiotic resistance genes (ARGs) stabilize in bacterial communities of temperate lakes, and these environments act as long-term reservoirs of ARGs. Still, it is not clear if the stabilization of the ARGs is caused by a periodical introduction, or by other factors regulated by dynamics within the water column. Here we observed the dynamics of the tetracycline resistance gene (tetA) and of the class 1 integron integrase gene intI1 a proxy of anthropogenic pollution in the water column and in the sediments of subalpine Lake Maggiore, together with several chemical, physical and microbiological variables. Both genes resulted more abundant within the bacterial community of the sediment compared to the water column and the water-sediment interface. Only at the inset of thermal stratification they reached quantifiable abundances in all the water layers, too. Moreover, the bacterial communities of the water-sediment interface were more similar to deep waters than to the sediments. These results suggest that the vertical distribution of tetA and intI1 is mainly due to the deposition of bacteria from the surface water to the sediment, while their resuspension from the sediment is less important.202031926010