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638600.9885Distribution of antibiotic and metal resistance genes in two glaciers of North Sikkim, India. Glacier studies as of late have ruffled many eyeballs, exploring this frigid ecology to understand the impact of climate change. Mapquesting the glaciers led to the discovery of concealed world of "psychrophiles" harboring in it. In the present study, the antibiotic resistance genes (ARGs) and heavy metal resistance genes (MRGs) were evaluated through both the culture-dependent and culture-independent methods. Samples were collected from two different glaciers, i.e., debris-covered glacier (Changme Khangpu) and debris-free glacier (Changme Khang). Functional metagenomics of both the glacier samples, provided evidence of presence of resistant genes against various antibiotic groups. Bacitracin resistant gene (bacA) was the predominant ARG in both the glaciers. MRGs in both the glacier samples were diversified as the genes detected were resistant against various heavy metals such as arsenic, tungsten, mercury, zinc, chromium, copper, cobalt, and iron. Unique MRGs identified from Changme Khangpu glacier were resistant to copper (cutA, cutE, cutC, cutF, cueR, copC, and copB) and chromium (yelf, ruvB, nfsA, chrR, and chrA) whereas, from Changme Khang glacier they showed resistance against cobalt (mgtA, dmef, corD, corC, corB, and cnrA), and iron (yefD, yefC, yefB, and yefA) heavy metals. ARGs aligned maximum identity with Gram-negative psychrotolerant bacteria. The cultured bacterial isolates showed tolerance to high concentrations of tested heavy metal solutions. Interestingly, some of the antibiotic resistant bacterial isolates also showed tolerance towards the higher concentrations of heavy metals. Thus, an introspection of the hypothesis of co-occurrence and/co-selection of ARGs and MRGs in such environments has been highlighted here.202032888596
46210.9874Discovery and characterization of genes conferring natural resistance to the antituberculosis antibiotic capreomycin. Metagenomic-based studies have predicted an extraordinary number of potential antibiotic-resistance genes (ARGs). These ARGs are hidden in various environmental bacteria and may become a latent crisis for antibiotic therapy via horizontal gene transfer. In this study, we focus on a resistance gene cph, which encodes a phosphotransferase (Cph) that confers resistance to the antituberculosis drug capreomycin (CMN). Sequence Similarity Network (SSN) analysis classified 353 Cph homologues into five major clusters, where the proteins in cluster I were found in a broad range of actinobacteria. We examine the function and antibiotics targeted by three putative resistance proteins in cluster I via biochemical and protein structural analysis. Our findings reveal that these three proteins in cluster I confer resistance to CMN, highlighting an important aspect of CMN resistance within this gene family. This study contributes towards understanding the sequence-structure-function relationships of the phosphorylation resistance genes that confer resistance to CMN.202338114770
455520.9873Characterization of known and novel clinically important antibiotic resistance genes and novel microbes from wastewater-impacted high Arctic fjord sediments. Arctic microbiota is enigmatic and highly underexplored. With the aim of understanding the resistome and microbiota of high-Arctic fjord sediments and the effect of wastewater discharge on sediment microbiota, we analyzed sediments from Advent fjord in Svalbard using metagenomics. We show the presence of 888 clinically relevant antibiotic resistance genes including genes coding resistance against last-resort antibiotics such as carbapenems, colistin, vancomycin, linezolid and tigecycline in the sediment microbiota. Using computational models, 478 novel β-lactamases belonging to 217 novel β-lactamase families were revealed in the sediment microbiota. Further, we identified hosts for 69 novel families and showed that these genes are widespread in the Arctic environment. We assembled 644 metagenome-assembled genomes (MAGs) from sediment metagenomes. Of these >97 % belonged to novel taxa with 89 bacterial MAGs representing seven putative novel phyla. These MAGs encoded important functions like nutrient cycling and methane metabolism etc. Our study demonstrated mixing of human associated bacteria and Arctic sediment microbiota. It provides the first comprehensive dataset of the distribution and diversity of novel microbes and β-lactamases in the wastewater-impacted high Arctic fjord sediments.202540424901
866730.9873Glacier-Fed Stream Biofilms Harbor Diverse Resistomes and Biosynthetic Gene Clusters. Antimicrobial resistance (AMR) is a universal phenomenon the origins of which lay in natural ecological interactions such as competition within niches, within and between micro- to higher-order organisms. To study these phenomena, it is crucial to examine the origins of AMR in pristine environments, i.e., limited anthropogenic influences. In this context, epilithic biofilms residing in glacier-fed streams (GFSs) are an excellent model system to study diverse, intra- and inter-domain, ecological crosstalk. We assessed the resistomes of epilithic biofilms from GFSs across the Southern Alps (New Zealand) and the Caucasus (Russia) and observed that both bacteria and eukaryotes encoded twenty-nine distinct AMR categories. Of these, beta-lactam, aminoglycoside, and multidrug resistance were both abundant and taxonomically distributed in most of the bacterial and eukaryotic phyla. AMR-encoding phyla included Bacteroidota and Proteobacteria among the bacteria, alongside Ochrophyta (algae) among the eukaryotes. Additionally, biosynthetic gene clusters (BGCs) involved in the production of antibacterial compounds were identified across all phyla in the epilithic biofilms. Furthermore, we found that several bacterial genera (Flavobacterium, Polaromonas, Superphylum Patescibacteria) encode both atimicrobial resistance genes (ARGs) and BGCs within close proximity of each other, demonstrating their capacity to simultaneously influence and compete within the microbial community. Our findings help unravel how naturally occurring BGCs and AMR contribute to the epilithic biofilms mode of life in GFSs. Additionally, we report that eukaryotes may serve as AMR reservoirs owing to their potential for encoding ARGs. Importantly, these observations may be generalizable and potentially extended to other environments that may be more or less impacted by human activity. IMPORTANCE Antimicrobial resistance is an omnipresent phenomenon in the anthropogenically influenced ecosystems. However, its role in shaping microbial community dynamics in pristine environments is relatively unknown. Using metagenomics, we report the presence of antimicrobial resistance genes and their associated pathways in epilithic biofilms within glacier-fed streams. Importantly, we observe biosynthetic gene clusters associated with antimicrobial resistance in both pro- and eukaryotes in these biofilms. Understanding the role of resistance in the context of this pristine environment and complex biodiversity may shed light on previously uncharacterized mechanisms of cross-domain interactions.202336688698
527940.9873Occurrence 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
386350.9867Antibiotic resistance in mucosal bacteria from high Arctic migratory salmonids. Two related salmonids, Arctic char (Salvelinus alpinus) and lake whitefish (Coregonus clupeaformis) sampled from the high Arctic region of Nunavut, Canada are anadromous fish, migrating annually from the same ice-covered freshwater waterbodies to spend summers in the marine waters of the Arctic Ocean. Microbiota associated with the skin-associated mucus undergo community change coincident with migration, and irrespective of this turnover, antibiotic resistance was detected in mixed bacterial cultures initiated with mucus samples. Although as expected most bacteria were unculturable, however, 5/7 isolates showed susceptibility to a panel of five common antibiotics. The fish were sampled under severe conditions and at remote locations far from human habitation. Regardless, two isolates, 'Carnobacterium maltaromaticum sm-2' and 'Arthrobacter citreus sm', showed multi-resistance to two or more antibiotics including ampicillin and streptomycin indicating multiple resistance genes. It is unknown if these fish bacteria have 'natural' resistance phenotypes or if resistance has been acquired. As result of these observations, we urge long-term monitoring of drug-resistant bacteria in the region and caution the assumption of a lack of drug-resistant organisms even in such extreme environments.202234109745
766760.9866Metagenomics uncovers microbiome and resistome in soil and reindeer faeces from Ny-Ålesund (Svalbard, High Arctic). Research on the microbiome and resistome in polar environments, such as the Arctic, is crucial for understanding the emergence and spread of antibiotic resistance genes (ARGs) in the environment. In this study, soil and reindeer faeces samples collected from Ny-Ålesund (Svalbard, High Arctic) were examined to analyze the microbiome, ARGs, and biocide/metal resistance genes (BMRGs). The dominant phyla in both soil and faeces were Pseudomonadota, Actinomycetota, and Bacteroidota. A total of 2618 predicted Open Reading Frames (ORFs) containing antibiotic resistance genes (ARGs) were detected. These ARGs belong to 162 different genes across 17 antibiotic classes, with rifamycin and multidrug resistance genes being the most prevalent. We focused on investigating antibiotic resistance mechanisms in the Ny-Ålesund environment by analyzing the resistance genes and their biological pathways. Procrustes analysis demonstrated a significant correlation between bacterial communities and ARG/BMRG profiles in soil and faeces samples. Correlation analysis revealed that Pseudomonadota contributed most to multidrug and triclosan resistance, while Actinomycetota were predominant contributors to rifamycin and aminoglycoside resistance. The geochemical factors, SiO(4)(2-) and NH(4)(+), were found to significantly influence the microbial composition and ARG distribution in the soil samples. Analysis of ARGs, BMRGs, virulence factors (VFs), and pathogens identified potential health risks associated with certain bacteria, such as Cryobacterium and Pseudomonas, due to the presence of different genetic elements. This study provided valuable insights into the molecular mechanisms and geochemical factors contributing to antibiotic resistance and enhanced our understanding of the evolution of antibiotic resistance genes in the environment.202439159777
735770.9866Metagenomic 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
47980.9866Genome sequences of Methylobacterium and Methylorubrum isolates from Cd-contaminated soils in the Tar Creek Superfund site. Soil bacteria were isolated from the Tar Creek Superfund site in the presence of cadmium. Eight of these strains belong to the genus Methylobacterium, whereas one strain belongs to the genus Methylorubrum. Here, we report drafts of their genome sequences and highlight cadmium-resistance genes required in an exceptionally contaminated environment.202539835800
518790.9866Recovery of 52 bacterial genomes from the fecal microbiome of the domestic cat (Felis catus) using Hi-C proximity ligation and shotgun metagenomics. We used Hi-C proximity ligation with shotgun sequencing to retrieve metagenome-assembled genomes (MAGs) from the fecal microbiomes of two domestic cats (Felis catus). The genomes were assessed for completeness and contamination, classified taxonomically, and annotated for putative antimicrobial resistance (AMR) genes.202337695121
2604100.9865Acquisition and dissemination of cephalosporin-resistant E. coli in migratory birds sampled at an Alaska landfill as inferred through genomic analysis. Antimicrobial resistance (AMR) in bacterial pathogens threatens global health, though the spread of AMR bacteria and AMR genes between humans, animals, and the environment is still largely unknown. Here, we investigated the role of wild birds in the epidemiology of AMR Escherichia coli. Using next-generation sequencing, we characterized cephalosporin-resistant E. coli cultured from sympatric gulls and bald eagles inhabiting a landfill habitat in Alaska to identify genetic determinants conferring AMR, explore potential transmission pathways of AMR bacteria and genes at this site, and investigate how their genetic diversity compares to isolates reported in other taxa. We found genetically diverse E. coli isolates with sequence types previously associated with human infections and resistance genes of clinical importance, including bla(CTX-M) and bla(CMY). Identical resistance profiles were observed in genetically unrelated E. coli isolates from both gulls and bald eagles. Conversely, isolates with indistinguishable core-genomes were found to have different resistance profiles. Our findings support complex epidemiological interactions including bacterial strain sharing between gulls and bald eagles and horizontal gene transfer among E. coli harboured by birds. Results suggest that landfills may serve as a source for AMR acquisition and/or maintenance, including bacterial sequence types and AMR genes relevant to human health.201829743625
478110.9865Plasmids of Psychrotolerant Polaromonas spp. Isolated From Arctic and Antarctic Glaciers - Diversity and Role in Adaptation to Polar Environments. Cold-active bacteria of the genus Polaromonas (class Betaproteobacteria) are important components of glacial microbiomes. In this study, extrachromosomal replicons of 26 psychrotolerant Polaromonas strains, isolated from Arctic and Antarctic glaciers, were identified, sequenced, and characterized. The plasmidome of these strains consists of 13 replicons, ranging in size from 3,378 to 101,077 bp. In silico sequence analyses identified the conserved backbones of these plasmids, composed of genes required for plasmid replication, stable maintenance, and conjugal transfer. Host range analysis revealed that all of the identified plasmids are narrow-host-range replicons, only able to replicate in bacteria of closely related genera (Polaromonas and Variovorax) of the Comamonadaceae family. Special attention was paid to the identification of plasmid auxiliary genetic information, which may contribute to the adaptation of bacteria to environmental conditions occurring in glaciers. Detailed analysis revealed the presence of genes encoding proteins potentially involved in (i) protection against reactive oxygen species, ultraviolet radiation, and low temperatures; (ii) transport and metabolism of organic compounds; (iii) transport of metal ions; and (iv) resistance to heavy metals. Some of the plasmids also carry genes required for the molecular assembly of iron-sulfur [Fe-S] clusters. Functional analysis of the predicted heavy metal resistance determinants demonstrated that their activity varies, depending on the host strain. This study provides the first molecular insight into the mobile DNA of Polaromonas spp. inhabiting polar glaciers. It has generated valuable data on the structure and properties of a pool of plasmids and highlighted their role in the biology of psychrotolerant Polaromonas strains and their adaptation to the environmental conditions of Arctic and Antarctic glaciers.201829967598
2605120.9864Satellite tracking of gulls and genomic characterization of faecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial-resistant Escherichia coli on the Kenai Peninsula, Alaska. Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well described. We equipped 17 landfill-foraging gulls with satellite transmitters and collected gull faecal samples longitudinally from four locations on the Kenai Peninsula, Alaska to assess: (a) gull attendance and transitions between sites, (b) spatiotemporal prevalence of faecally shed AMR E. coli, and (c) genomic relatedness of AMR E. coli isolates among sites. We also sampled Pacific salmon (Oncorhynchus spp.) harvested as part of personal-use dipnet fisheries at two sites to assess potential contamination with AMR E. coli. Among our study sites, marked gulls most commonly occupied the lower Kenai River (61% of site locations) followed by the Soldotna landfill (11%), lower Kasilof River (5%) and upper Kenai River (<1%). Gulls primarily moved between the Soldotna landfill and the lower Kenai River (94% of transitions among sites), which were also the two locations with the highest prevalence of AMR E. coli. There was relatively high spatial and temporal variability in AMR E. coli prevalence in gull faeces and there was no evidence of contamination on salmon harvested in personal-use fisheries. We identified E. coli sequence types and AMR genes of clinical importance, with some isolates possessing genes associated with resistance to as many as eight antibiotic classes. Our findings suggest that gulls acquire AMR E. coli at habitats with anthropogenic inputs and subsequent movements may represent pathways through which AMR is dispersed.201930980689
8714130.9863Tales from the tomb: the microbial ecology of exposed rock surfaces. Although a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone-associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone-associated communities also had distinct functional attributes, with granite-associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock-dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre-disposed to different ecological strategies (symbiotic versus free-living lifestyles) depending on the rock type.201829235707
4363140.9863Structural and molecular rationale for the diversification of resistance mediated by the Antibiotic_NAT family. The environmental microbiome harbors a vast repertoire of antibiotic resistance genes (ARGs) which can serve as evolutionary predecessors for ARGs found in pathogenic bacteria, or can be directly mobilized to pathogens in the presence of selection pressures. Thus, ARGs from benign environmental bacteria are an important resource for understanding clinically relevant resistance. Here, we conduct a comprehensive functional analysis of the Antibiotic_NAT family of aminoglycoside acetyltransferases. We determined a pan-family antibiogram of 21 Antibiotic_NAT enzymes, including 8 derived from clinical isolates and 13 from environmental metagenomic samples. We find that environment-derived representatives confer high-level, broad-spectrum resistance, including against the atypical aminoglycoside apramycin, and that a metagenome-derived gene likely is ancestral to an aac(3) gene found in clinical isolates. Through crystallographic analysis, we rationalize the molecular basis for diversification of substrate specificity across the family. This work provides critical data on the molecular mechanism underpinning resistance to established and emergent aminoglycoside antibiotics and broadens our understanding of ARGs in the environment.202235338238
3958150.9862Antimicrobial-Resistant Bacteria Carriage in Rodents According to Habitat Anthropization. It is increasingly suggested that the dynamics of antimicrobial-resistant bacteria in the wild are mostly anthropogenically driven, but the spatial and temporal scales at which these phenomena occur in landscapes are only partially understood. Here, we explore this topic by studying antimicrobial resistance in the commensal bacteria from micromammals sampled at 12 sites from a large heterogenous landscape (the Carmargue area, Rhone Delta) along a gradient of anthropization: natural reserves, rural areas, towns, and sewage-water treatment plants. There was a positive relationship between the frequency of antimicrobial-resistant bacteria and the level of habitat anthropization. Although low, antimicrobial resistance was also present in natural reserves, even in the oldest one, founded in 1954. This study is one of the first to support the idea that rodents in human-altered habitats are important components of the environmental pool of resistance to clinically relevant antimicrobials and also that a "One Health" approach is required to assess issues related to antimicrobial resistance dynamics in anthropized landscapes.202337140742
489160.9862Symbiotic interactions between free-living amoeba and harboured mercury-resistant bacteria. A co-culture of environmental Acanthamoeba sp. associated to Hg-sensitive, narrow or broad-spectrum Hg-resistant Aeromonas sp. strains was exposed to HgCl(2) and phenylmercuric acetate. Amoebic growth depended on the Hg-resistance determinants of harboured bacteria. This laboratory model helped in understanding the mechanisms of Hg-resistance observed in amoeba isolated in river waters after a mercuric pollution. Amoeba acquired Hg-resistance by using symbiotic resistant bacteria.199323195537
7358170.9861Global 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
7685180.9861Gut heavy metal and antibiotic resistome of humans living in the high Arctic. Contaminants, such as heavy metals (HMs), accumulate in the Arctic environment and the food web. The diet of the Indigenous Peoples of North Greenland includes locally sourced foods that are central to their nutritional, cultural, and societal health but these foods also contain high concentrations of heavy metals. While bacteria play an essential role in the metabolism of xenobiotics, there are limited studies on the impact of heavy metals on the human gut microbiome, and it is so far unknown if and how Arctic environmental contaminants impact the gut microbes of humans living in and off the Arctic environment. Using a multiomics approach including amplicon, metagenome, and metatranscriptome sequencing, we identified and assembled a near-complete (NC) genome of a mercury-resistant bacterial strain from the human gut microbiome, which expressed genes known to reduce mercury toxicity. At the overall ecological level studied through α- and β-diversity, there was no significant effect of heavy metals on the gut microbiota. Through the assembly of a high number of NC metagenome-assembled genomes (MAGs) of human gut microbes, we observed an almost complete overlap between heavy metal-resistant strains and antibiotic-resistant strains in which resistance genes were all located on the same genetic elements.202439539714
476190.9861Adaptation in toxic environments: comparative genomics of loci carrying antibiotic resistance genes derived from acid mine drainage waters. Several studies have suggested the existence of a close relationship between antibiotic-resistant phenotypes and resistance to other toxic compounds such as heavy metals, which involve co-resistance or cross-resistance mechanisms. A metagenomic library was previously constructed in Escherichia coli with DNA extracted from the bacterial community inhabiting an acid mine drainage (AMD) site highly contaminated with heavy metals. Here, we conducted a search for genes involved in antibiotic resistance using this previously constructed library. In particular, resistance to antibiotics was observed among five clones carrying four different loci originating from CARN5 and CARN2, two genomes reconstructed from the metagenomic data. Among the three CARN2 loci, two carry genes homologous to those previously proposed to be involved in antibiotic resistance. The third CARN2 locus carries a gene encoding a membrane transporter with an unknown function and was found to confer bacterial resistance to rifampicin, gentamycin, and kanamycin. The genome of Thiomonas delicata DSM 16361 and Thiomonas sp. X19 were sequenced in this study. Homologs of genes carried on these three CARN2 loci were found in these genomes, two of these loci were found in genomic islands. Together, these findings confirm that AMD environments contaminated with several toxic metals also constitute habitats for bacteria that function as reservoirs for antibiotic resistance genes.201829090447