Study of indiscriminate distribution of restrained antimicrobial resistome of different environmental niches. - Related Documents




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729001.0000Study of indiscriminate distribution of restrained antimicrobial resistome of different environmental niches. Prophylactic usage and high persistent nature of several antibiotics have put selective pressure on the native microbial population that led to the emergence, propagation, and persistence of antibiotic resistance in nature. The surveillance of antibiotic resistome pattern and identification of points of intervention throughout the different environmental habitats will help to break the flow of antibiotic resistance from environmental bacteria to human pathogens. The present study compares the occurrence, diversity, and abundance of ARGs in industrial sludge, wetland sludge, and sediment sample contaminated with pharmaceutical discharge. Metagenomes were mined for the presence of ARGs against the ResFinder 3.2 database using BLASTn program. Pharmaceutical sample (2.52%) showed high degree of ARG abundance and richness as compared with ETP sludge (2.28%) and wetland sludge samples (1.29%). The modern resistome pattern represented by critically important resistance genes against tetracycline (tetA, tetC, tetW, tetT, and tetS/M) and quinolone (qnrS, qnrVC, and qnrD) was identified in pharmaceutical sediment sample. However, effluent treatment plant (ETP) sludge sample showed abundance of multidrug efflux pumps indicating the presence of primitive resistome profile. In conclusion, the indiscriminate distribution pattern of antibiotic resistance genes in three selected environmental sites suggests enrichment and distribution of environmental niche-driven resistance. The study also suggests effluent discharge site from pharmaceutical industries and ETPs as pivotal points of intervention for the mitigation of antibiotic resistance.202133099734
729310.9999Prevalence and transmission of antibiotic resistance and microbiota between humans and water environments. The transmission routes for antibiotic resistance genes (ARGs) and microbiota between humans and water environments is poorly characterized. Here, we used high-throughput qPCR analyses and 16S rRNA gene sequencing to examine the occurrence and abundance of antibiotic resistance genes and microbiota in both healthy humans and associated water environments from a Chinese village. Humans carried the most diverse assemblage of ARGs, with 234 different ARGs being detected. The total abundance of ARGs in feces, on skin, and in the effluent from domestic sewage treatment systems were approximately 23, 2, and 7 times higher than their abundance in river samples. In total, 53 ARGs and 28 bacteria genera that were present in human feces could also be found in the influent and effluent of rural sewage treatment systems, and also downstream of the effluent release point. We identified the bacterial taxa that showed a significant association with ARGs (P < 0.01, r > 0.8) by network analysis, supporting the idea that these bacteria could carry some ARGs and transfer between humans and the environment. Analysis of ARGs and microbiota in humans and in water environments helps to define the transmission routes and dynamics of antibiotic resistance within these environments. This study highlights human contribution to the load of ARGs into the environment and suggests means to prevent such dissemination.201830420129
728320.9999Comparative metagenomics reveals a diverse range of antimicrobial resistance genes in effluents entering a river catchment. The aquatic environment has been implicated as a reservoir for antimicrobial resistance genes (ARGs). In order to identify sources that are contributing to these gene reservoirs, it is crucial to assess effluents that are entering the aquatic environment. Here we describe a metagenomic assessment for two types of effluent entering a river catchment. We investigated the diversity and abundance of resistance genes, mobile genetic elements (MGEs) and pathogenic bacteria. Findings were normalised to a background sample of river source water. Our results show that effluent contributed an array of genes to the river catchment, the most abundant being tetracycline resistance genes tetC and tetW from farm effluents and the sulfonamide resistance gene sul2 from wastewater treatment plant (WWTP) effluents. In nine separate samples taken across 3 years, we found 53 different genes conferring resistance to seven classes of antimicrobial. Compared to the background sample taken up river from effluent entry, the average abundance of genes was three times greater in the farm effluent and two times greater in the WWTP effluent. We conclude that effluents disperse ARGs, MGEs and pathogenic bacteria within a river catchment, thereby contributing to environmental reservoirs of ARGs.201627054725
729130.9999Accumulation of clinically relevant antibiotic-resistance genes, bacterial load, and metals in freshwater lake sediments in Central Europe. Wastewater treatment plants (WWTP) receive the effluents from various sources (communities, industrial, and hospital effluents) and are recognized as reservoir for antibiotic-resistance genes (ARGs) that are associated with clinical pathogens. The aquatic environment is considered a hot-spot for horizontal gene transfer, and lake sediments offer the opportunity for reconstructing the pollution history and evaluating the impacts. In this context, variation with depth and time of the total bacterial load, the abundance of faecal indicator bacteria (FIB; E. coli and Enterococcus spp. (ENT)), Pseudomonas spp., and ARGs (blaTEM, blaSHV, blaCTX-M, blaNDM, and aadA) were quantified in sediment profiles of different parts of Lake Geneva using quantitative PCR. The abundance of bacterial marker genes was identified in sediments contaminated by WWTP following eutrophication of the lake. Additionally, ARGs, including the extended-spectrum ß-lactam- and aminoglycoside-resistance genes, were identified in the surface sediments. The ARG and FIB abundance strongly correlated (r ≥ 0.403, p < 0.05, n = 34) with organic matter and metal concentrations in the sediments, indicating a common and contemporary source of contamination. The contamination of sediments by untreated or partially treated effluent water can affect the quality of ecosystem. Therefore, the reduction of contaminants from the source is recommended for further improvement of water quality.201525933054
319740.9999Antibiotic resistance and pathogen spreading in a wastewater treatment plant designed for wastewater reuse. Climate change significantly contributes to water scarcity in various regions worldwide. While wastewater reuse is a crucial strategy for mitigating water scarcity, it also carries potential risks for human health due to the presence of pathogenic and antibiotic resistant bacteria (ARB). Antibiotic resistance represents a Public Health concern and, according to the global action plan on antimicrobial resistance, wastewater role in selecting and spreading ARB must be monitored. Our aim was to assess the occurrence of ARB, antibiotic resistance genes (ARGs), and potential pathogenic bacteria throughout a wastewater treatment plant (WWTP) designed for water reuse. Furthermore, we aimed to evaluate potential association between ARB and ARGs with antibiotics and heavy metals. The results obtained revealed the presence of ARB, ARGs and pathogenic bacteria at every stage of the WWTP. Notably, the most prevalent ARB and ARG were sulfamethoxazole-resistant bacteria (up to 7.20 log CFU mL(-1)) and sulII gene (up to 5.91 log gene copies mL(-1)), respectively. The dominant pathogenic bacteria included Arcobacter, Flavobacterium and Aeromonas. Although the abundance of these elements significantly decreased during treatment (influent vs. effluent, p < 0.05), they were still present in the effluent designated for reuse. Additionally, significant correlations were observed between heavy metal concentrations (copper, nickel and selenium) and antibiotic resistance elements (ampicillin-resistant bacteria, tetracycline-resistant bacteria, ARB total abundance and sulII) (p < 0.05). These results underscore the importance of monitoring the role of WWTP in spreading antibiotic resistance, in line with the One Health approach. Additionally, our findings suggest the need of interventions to reduce human health risks associated with the reuse of wastewater for agricultural purposes.202439357555
321250.9999Distribution and driving factors of antibiotic resistance genes in treated wastewater from different types of livestock farms. Treated wastewater from livestock farms is an important reservoir for antibiotic resistance genes (ARGs), and is a main source of ARGs in the environment. However, the distribution and driving factors of ARGs in treated wastewater from different types of livestock farms are rarely reported. In this study, treated wastewater from 69 large-scale livestock farms of different types, including broiler, layer, and pig farms, was collected, and 11 subtypes of ARGs, 2 mobile genetic elements (MGEs) and bacterial community structure were analyzed. The results revealed detection rates of NDM-1 and mcr-1 of 90 % and 43 %, respectively, and the detection rates of other ARGs were 100 %. The relative abundance of ARGs, such as tetA, tetX and strB, in broiler farms was significantly higher than that in layer farms, but the bacterial α diversity was significantly lower than that in other farm types. Furthermore, although the treatment process had a greater impact on the physicochemical properties of the treated wastewater than the livestock type, livestock type was the main factor affecting the bacterial community in the treated wastewater. The analysis of potential host bacteria of ARGs revealed significant differences in the host bacteria of ARGs in treated wastewater from different types of livestock farms. The host bacteria of ARGs in broiler farms mainly belonged to Actinobacteria, layer farms mainly belonged to Proteobacteria, and pig farms mainly belonged to Firmicutes. Additionally, redundancy analysis showed that the distribution of ARGs may have resulted from the combination of multiple driving factors in different types of livestock farms, among which tnpA and NH(4)(+)-N were the main influencing factors. This study revealed multiple driving factors for the distribution of typical ARGs in treated wastewater from different types of livestock farms, providing basic data for the prevention and control of ARG pollution in agricultural environments.202235934031
321360.9999Investigating antibiotics, antibiotic resistance genes, and microbial contaminants in groundwater in relation to the proximity of urban areas. Groundwater is an essential public and drinking water supply and its protection is a goal for global policies. Here, we investigated the presence and prevalence of antibiotic residues, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial contamination in groundwater environments at various distances from urban areas. Antibiotic concentrations ranged from below detection limit to 917 ng/L, being trimethoprim, macrolide, and sulfonamide the most abundant antibiotic classes. A total of eleven ARGs (aminoglycoside, β-lactam, chloramphenicol, Macrolide-Lincosamide-Streptogramin B - MLSB, sulfonamide, and tetracycline), one antiseptic resistance gene, and two MGEs were detected by qPCR with relative abundances ranging from 6.61 × 10(-7) to 2.30 × 10(-1) copies/16S rRNA gene copies. ARGs and MGEs were widespread in the investigated groundwater environments, with increased abundances not only in urban, but also in remote areas. Distinct bacterial community profiles were observed, with a higher prevalence of Betaproteobacteria and Bacteroidetes in the less-impacted areas, and that of Firmicutes in the contaminated groundwater. The combined characteristics of increased species diversity, distinct phylogenetic composition, and the possible presence of fecal and/or pathogenic bacteria could indicate different types of contamination. Significant correlations between ARGs, MGEs and specific taxa within the groundwater bacterial community were identified, revealing the potential hosts of resistance types. Although no universal marker gene could be determined, a co-selection of int1, qacEΔ1 and sulI genes, a proxy group for anthropogenic pollution, with the tetC, tetO, tetW resistance genes was identified. As the tet group was observed to follow the pattern of environmental contamination for the groundwater samples investigated in this study, our results strongly support the proposal of this group of genes as an environmental tracer of human impact. Overall, the present study investigated several emerging contaminants in groundwater habitats that may be included in monitoring programs to enable further regulatory and protection measures.201829454283
711570.9999Antibiotics, antibiotic resistance and associated risk in natural springs from an agroecosystem environment. This study investigates the occurrence, transport, and risks associated to antibiotic residues, antibiotic resistance genes (ARGs) and antibiotic resistant Escherichia coli (AR-E. coli) in eleven natural springs in an agroecosystem environment with intense livestock production, where groundwater nitrate concentration usually sets above 50 mg L(-1). Out of 23 multiple-class antibiotics monitored, tetracycline and sulfonamide residues were the most ubiquitous, and they were detected at concentrations ranging from ng L(-1) to μg L(-1). Five ARGs were monitored, conferring resistance to the antibiotic classes of major use in livestock production. Thus, genes conferring resistance to sulfonamides (sul1 and sul2) and tetracyclines (tetW) as well as a gene proxy for anthropogenic pollution (intI1) were present in most springs. sul1 was the most abundant, with absolute concentrations ranging from 4 × 10(2) to 5.6 × 10(6) gene copies L(-1) water. AR-E. coli showing resistance to sulfonamides and tetracyclines was also detected, with a prevalence up to approximately 40 % in some sites but with poor correlations with the concentration of antibiotic residues and ARGs. The occurrence of antibiotics, ARGs and AR-E. coli was characterized by large seasonal variations which were mostly associated to both hydrological factors and reactive transport processes. Finally, a risk assessment approach pointed out towards low risk for both the groundwater environment and human health, when spring water is used for direct human consumption, associated with the occurrence of antibiotics, ARGs and AR-E. coli. However, long-term effects cannot be neglected, and proper actions must be taken to preserve groundwater quality.202336208750
532980.9999Distribution of Antibiotic Resistance in a Mixed-Use Watershed and the Impact of Wastewater Treatment Plants on Antibiotic Resistance in Surface Water. The aquatic environment has been recognized as a source of antibiotic resistance (AR) that factors into the One Health approach to combat AR. To provide much needed data on AR in the environment, a comprehensive survey of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues was conducted in a mixed-use watershed and wastewater treatment plants (WWTPs) within the watershed to evaluate these contaminants in surface water. A culture-based approach was used to determine prevalence and diversity of ARB in surface water. Low levels of AR Salmonella (9.6%) and Escherichia coli (6.5%) were detected, while all Enterococcus were resistant to at least one tested antibiotic. Fewer than 20% of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (17.3%) and carbapenem-resistant Enterobacteriaceae (CRE) (7.7%) were recovered. Six ARGs were detected using qPCR, primarily the erythromycin-resistance gene, ermB. Of the 26 antibiotics measured, almost all water samples (98.7%) had detectable levels of antibiotics. Analysis of wastewater samples from three WWTPs showed that WWTPs did not completely remove AR contaminants. ARGs and antibiotics were detected in all the WWTP effluent discharges, indicating that WWTPs are the source of AR contaminants in receiving water. However, no significant difference in ARGs and antibiotics between the upstream and downstream water suggests that there are other sources of AR contamination. The widespread occurrence and abundance of medically important antibiotics, bacteria resistant to antibiotics used for human and veterinary purposes, and the genes associated with resistance to these antibiotics, may potentially pose risks to the local populations exposed to these water sources.202337998788
728490.9999Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes. Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.201525913323
5354100.9999Cultivation-dependent and high-throughput sequencing approaches studying the co-occurrence of antibiotic resistance genes in municipal sewage system. During the past years, antibiotic-resistant bacteria (ARB) leading for the spreading of antibiotic resistance genes (ARGs) became a global problem, especially multidrug-resistant (MDR) bacteria are considered the prime culprit of antibiotic resistance. However, the correlation between the antibiotic-resistant phenotype and the ARG profiles remains poorly understood. In the present study, metagenomic functional screening and metagenomic analysis of coliforms were combined to explore the phenotype and genotype of the ARBs from municipal sewage. Our results showed that the ARG co-occurrence was widespread in the municipal sewage. The present study also highlighted the high abundance of ARGs from antibiotic resistance coliforms especially the MDR coliforms with ARG level of 33.8 ± 4.2 copies per cell. The ARG profiles and the antibiotic resistance phenotypes of the isolated antibiotic resistant coliforms were also correlated and indicated that the resistance to the related antibiotic (ampicillin, kanamycin, erythromycin, chloramphenicol, and tetracycline) was mostly contributed by the ARGs belonging to the subtypes of β-lactamase, aminoglycoside 3-phosphotransferase, phosphotransferase type 2, chloramphenicol acetyltransferase, tetA, etc.201729034431
3677110.9999Prevalence of sulfonamide-resistant bacteria, resistance genes and integron-associated horizontal gene transfer in natural water bodies and soils adjacent to a swine feedlot in northern Taiwan. Antibiotics are commonly used in swine feed to treat and prevent disease, as well as to promote growth. Antibiotics released into the environment via wastewater could accelerate the emergence of antibiotic-resistant bacteria and resistance genes in the surrounding environment. In this study, we quantified the occurrence of sulfonamides, sulfonamide-resistant microorganisms and resistance genes in the wastewater from a swine farm in northern Taiwan and its surrounding natural water bodies and soils. Sulfonamide levels were similar in the receiving downstream and upstream river water. However, the prevalence of sulfonamide-resistant bacteria and resistance genes, as analyzed by cultivation-dependent and -independent molecular approaches, was significantly greater in the downstream compared to the upstream river water samples. Barcoded-pyrosequencing revealed a highly diverse bacterial community structure in each sample. However, the sequence identity of the sulfonamide resistance gene sul1 in the wastewater and downstream environment samples was nearly identical (99-100%). The sul1 gene, which is genetically linked to class 1 integrons, was dominant in the downstream water bodies and soils. In conclusion, the increased prevalence of sulfonamide resistance genes in the wastewater from a swine farm, independent of the persistent presence of sulfonamides, could be a potential source of resistant gene pools in the surrounding environment.201424637153
3098120.9999Bacterial Communities and Resistance and Virulence Genes in Hospital and Community Wastewater: Metagenomic Analysis. Metagenomic studies have made it possible to deepen the analysis of the abundance of bacterial populations that carry resistance and virulence determinants in the wastewater environment. In this study, a longitudinal collection of samples of community and hospital wastewater from August 2021 to September 2022 was obtained. Shotgun metagenomic sequencing and bioinformatic analysis were performed to characterize the bacterial abundance, antimicrobial resistance genes (ARGs), plasmids, and virulence factor genes (VFGs) contained in the wastewater. The microbial composition of the community and hospital wastewater showed that the most abundant bacterial phyla detected in all samples were: Proteobacteria, Bacteroides, Firmicutes, Campylobacterota, and Actinobacteria. Seasonal differences in the relative abundances of species, ARGs, plasmids, and VFGs were observed. In this study, a total of 270 ARGs were detected, and it was found that the absolute abundance of ARGs only showed a 39% reduction in the treated wastewater. Furthermore, the ARGs detected in this study were found to encode resistance to antibiotics of the last choice. Our results showed that plasmids carrying resistance genes were more abundant in raw wastewater, and 60% more abundant in hospital wastewater compared to community wastewater. Several of the VFGs detected in this study encode for adhesion, motility, and biofilm formation, which likely allows bacteria to remain and persist in the wastewater environment and survive WWTP treatment systems, thus managing to escape into the environment via treated wastewater.202540076673
7294130.9999The Sources and Potential Hosts Identification of Antibiotic Resistance Genes in the Yellow River, Revealed by Metagenomic Analysis. The fate of antibiotic resistance genes (ARGs) has been revealed in various environmental media in recent years. Namely, the emergence of genes that resist colistin and carbapenems has attracted wide attention. However, the pollution condition of ARGs and sources in the Yellow River is still little understood, despite the river being the second longest in China. The present study determined the levels of ARG pollution in the Henan section of the Yellow River and evaluated the role of the aquaculture industry in the spread of ARGs. As revealed by the results, a total of 9 types of ARGs were detected in the sediments of the Yellow River, and the total ARG content in the Yellow River ranges from 7.27 to 245.45 RPKM. Sul1 and sul2 are the dominant ARGs, and the huge usage of sulfonamides, horizontal gene transfer, and wide bacteria host contribute to the prevalence of these two genes. The results of Spearman correlation analysis indicate that the breeding industry has little influence on ARGs in the Yellow River. Network analysis reveals that the opportunistic pathogen Pseudomonas is the potential host of sul1, tetG, and ANT(3'')-IIa, which can pose a risk to human health.202236012061
3678140.9999Abundance and dynamics of antibiotic resistance genes and integrons in lake sediment microcosms. Antibiotic resistance in bacteria causing disease is an ever growing threat to the world. Recently, environmental bacteria have become established as important both as sources of antibiotic resistance genes and in disseminating resistance genes. Low levels of antibiotics and other pharmaceuticals are regularly released into water environments via wastewater, and the concern is that such environmental contamination may serve to create hotspots for antibiotic resistance gene selection and dissemination. In this study, microcosms were created from water and sediments gathered from a lake in Sweden only lightly affected by human activities. The microcosms were exposed to a mixture of antibiotics of varying environmentally relevant concentrations (i.e., concentrations commonly encountered in wastewaters) in order to investigate the effect of low levels of antibiotics on antibiotic resistance gene abundances and dynamics in a previously uncontaminated environment. Antibiotic concentrations were measured using liquid chromatography-tandem mass spectrometry. Abundances of seven antibiotic resistance genes and the class 1 integron integrase gene, intI1, were quantified using real-time PCR. Resistance genes sulI and ermB were quantified in the microcosm sediments with mean abundances 5 and 15 gene copies/10(6) 16S rRNA gene copies, respectively. Class 1 integrons were determined in the sediments with a mean concentration of 3.8 × 10(4) copies/106 16S rRNA gene copies. The antibiotic treatment had no observable effect on antibiotic resistance gene or integron abundances.201425247418
3097150.9999Investigation of the Prevalence of Antibiotic Resistance Genes According to the Wastewater Treatment Scale Using Metagenomic Analysis. Although extensive efforts have been made to investigate the dynamics of the occurrence and abundance of antibiotic resistance genes (ARGs) in wastewater treatment plants (WWTPs), understanding the acquisition of antibiotic resistance based on the WWTP scale and the potential effects on WWTPs is of relatively less interest. In this study, metagenomic analysis was carried out to investigate whether the WWTP scale could be affected by the prevalence and persistence of ARGs and mobile genetic elements (MGEs). As a result, 152 ARG subtypes were identified in small-scale WWTP samples, while 234 ARG subtypes were identified in large-scale WWTP samples. Among the detectable ARGs, multidrug, MLS (macrolide-lincosamide-streptogramin), sulfonamide, and tetracycline resistance genes had the highest abundance, and large and small WWTPs had similar composition characteristics of ARGs. In MGE analysis, plasmids and integrons were 1.5-2.0-fold more abundant in large-scale WWTPs than in small-scale WWTPs. The profile of bacteria at the phylum level showed that Proteobacteria and Actinobacteria were the most dominant bacteria, representing approximately 70% across large- and small-scale WWTPs. Overall, the results of this study elucidate the different abundances and dissemination of ARGs between large- and small-scale WWTPs, which facilitates the development of next-generation engineered wastewater treatment systems.202133671905
6868160.9999Rare resistome rather than core resistome exhibited higher diversity and risk along the Yangtze River. As important freshwater ecosystems, the occurrence and distribution of antibiotic resistance genes (ARGs) in rivers are relevant to public health. However, studies investigating ARGs of different environmental media in river ecosystems are limited. In this study, we analyzed the ARGs of microbes in free-living setting, particle-associated setting, sediment and bank soil of the Yangtze River using metagenomics. Twenty-six ARGs were found in all samples regardless of media (core resistome) with a diversity of 8.6 %-34.7 %, accounting for 22.7 %-89.2 % of the relative abundance of the overall ARGs. The core resistome of the Yangtze River was dominated by multidrug resistance genes consisting mainly of efflux pumps and bacitracin resistance genes. The rare resistome was dominated by multidrug, sulfonamide, and aminoglycoside resistance genes. The core resistome was more prevalent in chromosomes, implying that these ARGs with low diversity and high relative abundance may be intrinsic to microbes in the Yangtze River. The rare resistome was more prevalent in plasmids, suggesting these ARGs with high diversity and low relative abundance were acquired under environmental stresses and had transfer potential. Additionally, we found that core and rare resistome were mainly carried by specific bacteria. Noteworthily, twenty-two ARGs of high clinical concern were identified in rare resistome, especially aac(6')-I, sul1, and tetM, which were plasmid-borne and hosted by clinically relevant pathogens. Both core and rare resistome hosts showed the highest niche breadths in particle-associated setting compared to other media, and particle-associated setting could provide more stable and ideal conditions for resistome hosts to survive. This study elucidated the genetic locations of ARGs and the community assembly mechanisms of ARG hosts in freshwater environments.202438039820
7106170.9999The swine waste resistome: Spreading and transfer of antibiotic resistance genes in Escherichia coli strains and the associated microbial communities. The overuse of antimicrobials in livestock farming has led to the development of resistant bacteria and the spread of antibiotic-resistant genes (ARGs) among animals. When manure containing these antibiotics is applied to agricultural fields, it creates a selective pressure that promotes the acquisition of ARGs by bacteria, primarily through horizontal gene transfer. Most research on ARGs focuses on their role in clinical antibiotic resistance and their transfer from environmental sources to bacteria associated with humans, such as Escherichia coli. The study investigates the spread of antibiotic-resistant genes (ARGs) through class 1 integrons in 27 Escherichia coli strains from pig manure. It focuses on six common ARGs (ermB, cmlA, floR, qnrS, tetA, and TEM) and the class 1 integron gene, assessing their prevalence in manure samples from three pig farms. The study found correlations and anticorrelations among these genes, indicating a predisposition of the integron in spreading certain ARGs. Specifically, cmlA and tetA genes were positively correlated with each other and negatively with int1, suggesting they are not transferred via Int1. Farm B had the highest int1 counts and a higher abundance of the TEM gene, but lower levels of cmlA and tetA genes. The results underscore the complexity of predicting ARG spread in agricultural environments and the associated health risks to humans through the food chain. The study's results offer valuable insights into the antibiotic-resistant genes (ARGs) profile in swine livestock, potentially aiding in the development of methods to trace ARGs in the environment.202439053184
3214180.9998Characteristics of the antibiotic resistance genes in the soil of medical waste disposal sites. The inappropriate disposal of medical waste allows bacteria to acquire antibiotic resistance, which results in a threat to public health. Antibiotic resistance gene (ARG) profiles were determined for 45 different soil samples containing medical waste and 15 nearby soil samples as controls. Besides physical and chemical analyses (i.e., dry matter content, pH value, and metal content), the genomes of microorganisms from the soil samples were extracted for high-throughput sequencing. ARG abundances of these samples were obtained by searching the metagenomic sequences against the antibiotic resistance gene database and the copies of ARGs per copy of the 16S rRNA gene at different levels were assessed. The results showed medical waste accumulation significantly enriched the contents of Cu, Cr, Pb, and As in the tested soil samples. Compared to the controls, the samples collected from areas containing medical waste were significantly enriched (p < 0.05, t-test) with ARGs annotated as sulfonamide and multidrug resistance genes, and in particular, the subtypes sul1 and sul2 (sulfonamide resistance genes), and multidrug_transporter (multidrug resistance gene). Moreover, the ARGs of the samples from the polluted areas were more diverse than those of the control samples (p < 0.05, t-test). The comparatively higher abundance and diversity of ARGs in contaminated soil pose a potential risk to human health.202032402966
7292190.9998Class 1 integron and related antimicrobial resistance gene dynamics along a complex freshwater system affected by different anthropogenic pressures. The risk for human health posed by polluted aquatic environments, and especially those carrying antibiotic resistance genes (ARGs) of clinical interest, is still debated. This is because of our limited knowledge of the dynamics of antimicrobial resistance in the environment, the selection mechanisms underlying the spread of ARGs, and the ecological factors potentially favoring their return to humans. The Class 1 integron is one of the most effective platforms for the dissemination of ARGs. In this study we investigated a freshwater system consisting of a lake-river-lake continuum, determining the abundance of class 1 integrons and their associated ARGs by a modulated metagenomic approach. Bacterial abundance and community composition were used to identify the potential carriers of class 1 integrons and their associated ARGs over a period of six months. Class 1 integrons and their ARG cargoes were significantly more abundant in riverine sampling sites receiving treated wastewater. Further, class 1 integrons carried ARGs ranked at the highest risk for human health (e.g., catB genes), in particular, genes encoding resistance to aminoglycosides. Genera of potential pathogens, such as Pseudomonas and Escherichia-Shigella, were correlated with class 1 integrons. The lake-river-lake system demonstrated a clear relationship between the integrase gene of class 1 integrons (intI1) and anthropogenic impact, but also a strong environmental filtering that favored the elimination of intI1 once the human derived stressors were reduced. Overall, the results of this study underline the role class 1 integrons as proxy of anthropogenic pollution and suggest this genetic platform as an important driver of aminoglycoside resistance genes, including high risk ARGs, of potential concern for human health.202336351483