Impact of coastal deoxygenation on antibiotic resistance gene profiles in size-fractionated bacterial communities. - Related Documents




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686001.0000Impact of coastal deoxygenation on antibiotic resistance gene profiles in size-fractionated bacterial communities. Oxygen loss disrupts marine ecosystems, threatening biodiversity and causing mass mortality of marine life. Antibiotic resistance genes (ARGs) pose a significant threat to human health by promoting the spread of resistant pathogens, making infections harder to treat and increasing mortality risks. However, the interplay between deoxygenation and ARG dynamics remains poorly understood. In this study, we employed time-series metagenomics to investigate the responses of ARG profiles in free-living (FL) and particle-associated (PA) fraction to oxygen loss during a 22-day summer deoxygenation event in the East China Sea. In total, we identified 1,186 ARG subtypes and 2,279 mobile genetic element (MGE) subtypes. The most dominant resistance classes of antibiotics were multidrug (23.5%), followed by tetracycline (15%), macrolide-lincosamide-streptogramin (13.4%), peptide (10.3%), glycopeptide (8.7%), aminoglycoside (7.3%), and beta-lactam (4.9%). We found that ARG richness in FL fraction increased with declining oxygen levels, particularly for beta-lactam and multidrug class, while no significant relationship was observed in the PA fraction. Although the total relative abundance of ARGs in both fraction showed no significant oxygen dependence, beta-lactam and multidrug resistance genes in FL fraction significantly increased with oxygen loss. Co-occurrence network analysis revealed stronger positive associations between ARGs and MGEs in the FL fraction, suggesting enhanced gene transfer among environmental bacteria. Furthermore, neutral community model analysis indicated that stochastic processes also played an interactive role in shaping ARG composition dynamics in both bacterial fractions. Our findings provide evidence that coastal deoxygenation preferentially enriches high-risk ARGs (e.g., beta-lactamase genes) in FL bacteria through MGE-mediated transfer, highlighting escalating antibiotic resistance risks that threaten both ecosystem and human health under climate warming. This study offers a framework for size-fractionated ARG monitoring and targeted mitigation strategies in coastal ecosystems.202540669246
686410.9999Metagenomics analysis revealing the occurrence of antibiotic resistome in salt lakes. Although antimicrobial resistance genes (ARGs) in dozens of environments have been well documented, the distribution of ARGs in salt lake ecosystems has been less intensively investigated. In this study, the broad-spectrum ARG profiles, microbial community composition and the comprehensive associations between microbiome and antimicrobial resistome in four salt lakes were investigated using a metagenomic approach. A total of 175 ARG subtypes affiliated with 19 ARG types were detected, and ARGs conferring resistance to multidrug, bacitracin, and macrolide-lincosamide-streptogramin (MLS) accounted for 71.2% of the total ARG abundance. However, the abundance of ARGs significantly decreased with the increasing salinity in the lakes. Both ARG profiles and microbial community structure presented remarkable discrepancies in different lakes, as well as in different sample types. Microbes such as genera Azoarcus, Aeromonas, Pseudomonas, and Kocuria, significantly co-occurred with multiple ARGs, indicating that these bacteria are potential ARG hosts in salt lake ecosystems. Collectively, this work provides new insights into the occurrence and distribution of ARGs in salt lake ecosystems.202134380279
688120.9999Spatiotemporal profiles and underlying mechanisms of the antibiotic resistome in two water-diversion lakes. Human-induced interventions have altered the local characteristics of the lake ecosystems through changes in hydraulic exchange, which in turn impacts the ecological processes of antibiotic resistance genes (ARGs) in the lakes. However, the current understanding of the spatiotemporal patterns and driving factors of ARGs in water-diversion lakes is still seriously insufficient. In the present study, we investigated antibiotic resistome in the main regulation and storage hubs, namely Nansi Lake and Dongping Lake, of the eastern part of the South-to-North Water Diversion project in Shandong Province (China) using a metagenomic-based approach. A total of 653 ARG subtypes belonging to 25 ARG types were detected with a total abundance of 0.125-0.390 copies/cell, with the dominance of bacitracin, multidrug, and macrolide-lincosamide streptogramin resistance genes. The ARG compositions were sensitive to seasonal variation and also interfered by artificial regulation structures along the way. Human pathogenic bacteria such as Acinetobacter calcoaceticus, Acinetobacter lwoffii, Klebsiella pneumoniae, along with the multidrug resistance genes they carried, were the focus of risk control in the two studied lakes, especially in summer. Plasmids were the key mobile genetic elements (MGEs) driving the horizontal gene transfer of ARGs, especially multidrug and sulfonamide resistance genes. The null model revealed that stochastic process was the main driver of ecological drift for ARGs in the lakes. The partial least squares structural equation model further determined that seasonal changes of pH and temperature drove a shift in the bacterial community, which in turn shaped the profile of ARGs by altering the composition of MGEs, antibacterial biocide- and metal-resistance genes (BMGs), and virulence factor genes (VFGs). Our results highlighted the importance of seasonal factors in determining the water transfer period. These findings can aid in a deeper understanding of the spatiotemporal variations of ARGs in lakes and their driving factors, offering a scientific basis for antibiotic resistance management.202439322056
688630.9998Bacterial community and antibiotic resistance genes assembly processes were shaped by different mechanisms in the deep-sea basins of the Western Pacific Ocean. As the intrinsic property of microorganisms, antibiotic resistance genes (ARGs) are fundamentally coupled to microbially-linked biogeochemical processes within ecosystems. However, human activities often obscure the natural distribution of ARGs through deterministic selective pressures. The deep-sea basin of the western Pacific Ocean is one of the least disturbed areas globally by human activities, providing a natural laboratory to investigate the intrinsic mechanisms governing ARGs in natural environments. In this study, we analyzed bacterial community and ARG diversity in 15 surface sediment samples from three deep-sea basins in the western Pacific Ocean. The relative abundance of ARGs in the surface sediments ranged from 3.10 × 10(-3) to 5.37 × 10(-2) copies/16S rRNA copies, with multidrug and β-lactam resistance genes dominated in all samples (49.06%-100%). The bacteria were mainly dominated by the Proteobacteria. The principal coordinate analysis (PCoA) showed significant spatial heterogeneity of ARGs and bacteria among the three basins. Null model, neutral community models (NCM), and normalized stochasticity ratio (NST) indicated that bacterial community was dominated by stochastic assembly, driven by geographic barriers leading to independent evolution. Conversely, the NST revealed that the ARGs profile was mainly shaped by deterministic processes. Environmental factors are more crucial than geographical factors and bacterial community for ARG occurrence among the selected factors. Meanwhile, we found that the spread of ARGs was mainly through vertical gene transfer in the pre-antibiotic era. The disparity between the assembly processes of bacterial community and ARGs may be attributed to the fact that ARG hosts were not the dominant bacteria in the community. This study first reported the distribution and assembly processes of ARGs and bacterial community in surface sediments of the western Pacific.202439481517
687040.9998Antibiotic resistome in landfill leachate and impact on groundwater. Landfill leachate is a hotspot in antibiotic resistance development. However, little is known about antibiotic resistome and host pathogens in leachate and their effects on surrounding groundwater. Here, metagenomic sequencing was used to explore profiles, host bacteria, environmental risks and influencing factors of antibiotic resistome in raw and treated leachate and surrounding groundwater of three landfills. Results showed detection of a total of 324 antibiotic resistance genes (ARGs). The ARGs conferring resistance to multidrug (8.8 %-25.7 %), aminoglycoside (13.1 %-39.2 %), sulfonamide (10.0 %-20.9 %), tetracycline (5.7 %-34.4 %) and macrolide-lincosamide-streptogramin (MLS, 5.3 %-29.5 %) were dominant in raw leachate, while multidrug resistance genes were the major ARGs in treated leachate (64.1 %-83.0 %) and groundwater (28.7 %-76.6 %). Source tracking analysis suggests non-negligible influence of leachate on the ARGs in groundwater. The pathogens including Acinetobacter pittii, Pseudomonas stutzeri and P. alcaligenes were the major ARG-carrying hosts. Variance partitioning analysis indicates that the microbial community, abiotic variables and their interaction contributed most to the antibiotic resistance development. Our results shed light on the dissemination and driving mechanisms of ARGs from leachate to the groundwater, indicating that a comprehensive risk assessment and efficient treatment approaches are needed to deal with ARGs in landfill leachate and nearby groundwater. ENVIRONMENTAL IMPLICATIONS: Antibiotic resistance genes are found abundant in the landfill sites, and these genes could be disseminated into groundwater via leaching of wastewater and infiltration of leachate. This results in deterioration of groundwater quality and human health risks posed by these ARGs and related pathogens. Thus measures should be taken to minimize potential negative impacts of landfills on the surrounding environment.202438547976
687750.9998Exploring urban coastal areas: Investigating the urban coastal areas as a reservoirs of antibiotic resistance Genes★. Antibiotic resistance genes (ARGs) have long served as adaptive defensive mechanisms among bacteria, enabling their survival and propagation in challenging environments. The consequences of inefficient wastewater treatment have culminated the emergence of untreatable and lethal extensively drug-resistant. To understand the relationship between wastewater effluent and marine ecosystems, we conducted a study to monitor the diversity and prevalence of common ARGs in Hong Kong's urban coastal areas at different seasons. Our findings revealed that sul 1 was the most abundant resistance gene, with an average relative abundance of 4.45 × 10(-2) per 16s rRNA gene copy. Moreover, temperature, dissolved oxygen, and salinity were key factors influencing seasonal variations in total ARGs abundance. The influence of environmental factors varied based on ARGs' association with Intl1, with Intl1-associated ARGs strongly correlating with temperature and dissolved oxygen. Notably, despite their abundance, sul1 and mphA exhibited similar correlations with both Intl1 and key environmental factors, suggesting these ARGs share a common dissemination mechanism. Moreover, the robust association between resistance genes and mobile genetic elements (MGE) could potentially act as a valuable indicator for assessing the efficacy of removing ARGs in wastewater treatment methods when operating under carefully optimized environmental parameters.202539642594
317660.9998Comprehensive profiling and risk assessment of antibiotic resistance genes in a drinking water watershed by integrated analysis of air-water-soil. The prevalence of antibiotic resistance genes (ARGs) in diverse habitats threatens public health. Watersheds represent critical freshwater ecosystems that interact with both the soil and atmosphere. However, a holistic understanding of ARGs distribution across these environmental media is currently inadequate. We profiled ARGs and bacterial communities in air-water-soil in the same watershed area during four seasons using high-throughput qPCR and 16S rRNA gene sequencing. Our findings demonstrated that aminoglycoside resistance genes (58.5%) were dominant in water, and multidrug resistance genes (55.2% and 54.2%) were dominant in soil and air. Five ARGs and nineteen bacterial genera were consistently detected in all samples, were named as shared genes or bacteria. Co-occurrence Network analysis revealed the co-occurrence module of resistance genes, mobile genetic elements (MGEs), and potential bacterial hosts, indicating that shared genes and bacteria may persist and co-spread across different environmental media. The risk assessment framework, based on ARGs' abundance, detection rate, and mobility, identified 33 high-risk ARGs. This is essential to evaluate the health risks of ARGs and to develop strategies to limit the threat of antibiotic resistance. Our study offers new insights into the risks associated with ARGs in the environment and suggests that ARGs may depend on specific bacterial cohabitants that co-exist with MGEs to facilitate their spread across environmental interfaces.202337742410
686170.9998Investigating the antibiotic resistance genes and mobile genetic elements in water systems impacted with anthropogenic pollutants. A wide range of pollutants, including heavy metals, endocrine-disrupting chemicals (EDCs), residual pesticides, and pharmaceuticals, are present in various water systems, many of which strongly drive the proliferation and dissemination of antimicrobial resistance genes (ARGs), heightening the antimicrobial resistance (AMR) crisis and creating a critical challenge for environmental and health management worldwide. This study addresses the impact of anthropogenic pollutants on AMR through an extensive analysis of ARGs and mobile genetic elements (MGEs) in urban wastewater, source water, and drinking water supplies in India. Results indicated that bla(TEM) and bla(CTXM-32) were the dominant ARGs across all water systems, underscoring the prevalence and dominance of resistance against β-lactam antibiotics. Moreover, transposase genes such as tnpA-02, tnp-04, and tnpA-05 were detected across all water systems, indicating potential mechanisms for genetic transfer. The ubiquitous presence of intI-1 and clin-intI-1 genes underscores the widespread dissemination of MGEs, posing challenges for water quality management. Besides, human pathogenic bacteria such as Clostridium, Acinetobacter, and Legionella were also detected, highlighting potential health risks associated with contaminated water. The identified pathogenic bacterial genera belong to the phyla Pseudomonadota and Firmicutes. Leveraging linear regression to analyze correlations between EDCs and ARG-MGEs provides deeper insights into their interconnected dynamics. DMP showed a significant influence on tnpA-02 (p = 0.005), tnpA-07 (p = 0.015), sul-1 (p = 0.008), intI-1 (p = 0.03), and clin-intI1 (p = 0.012), while DiNOP demonstrated a very high impact on tnpA-05 (p = 0). Redundancy analysis revealed significant correlations between resistance genes and EDCs. Additionally, environmental parameters such as pH were highly correlated with the majority of MGEs and bla(CTXM-32). Furthermore, we found that F(-), NO(-3), and SO(4)(-2) were significantly correlated with sul-1, with F(-) exhibiting the highest impact, emphasizing the intricate interplay of pollutants in driving AMR. Understanding these interconnected factors is crucial for developing effective strategies and sustainable solutions to combat antibiotic resistance in environmental settings.202539824274
317780.9998Metagenomic investigation of antibiotic resistance genes and resistant bacteria contamination in pharmaceutical plant sites in China. Pharmaceutical plant sites play a significant role in the dissemination of antibiotic resistance genes (ARGs) into the environment. It is imperative to comprehensively monitor of ARGs across various environmental media at these sites. This study focused on three pharmaceutical plants, two located in North China and one in South China. Through metagenomic approaches, we examined the composition, mobility potential, and bacterial hosts of ARGs in diverse media such as process water, groundwater, topsoil, soil cores, and pharmaceutical fermentation residues across diverse environmental matrices, including topsoil, soil cores, process water, groundwater, and pharmaceutical fermentation residues. We identified a wide array of ARGs, comprising 21 types and 740 subtypes, with process water exhibiting the highest abundance and diversity. Treatment processes varied in their efficacy in eliminating ARGs, and the clinically relevant ARGs should also be considered when evaluating wastewater treatment plant efficiency. Geographical distinctions in groundwater ARG distribution between northern and southern regions were observed. Soil samples from the three sites showed minimal impact from pharmaceutical activity, with vancomycin-resistance genes being the most prevalent. High levels of ARGs in pharmaceutical fermentation residues underscore the necessity for improved waste management practices. Metagenomic assembly revealed that plasmid-mediated ARGs were more abundant than chromosome-mediated ARGs. Metagenome-assembled genomes (MAGs) analysis identified 166 MAGs, with 62 harboring multiple ARGs. Certain bacteria tended to carry specific types of ARGs, revealing distinct host-resistance associations. This study enhances our understanding of ARG dissemination across different environmental media within pharmaceutical plants and underscores the importance of implementing strict regulations for effluent and residue discharge to control ARG spread.202438960118
686990.9998Contaminant-degrading bacteria are super carriers of antibiotic resistance genes in municipal landfills: A metagenomics-based study. Municipal landfills are hotspot sources of antimicrobial resistance (AMR) and are also important habitats of contaminant-degrading bacteria. However, high diversity of antibiotic resistance genes (ARGs) in landfills hinders assessing AMR risks in the affected environment. More concerned, whether there is co-selection or enrichment of antibiotic-resistant bacteria and contaminant-degrading bacteria in these extremely polluted environments is far less understood. Here, we collected metagenomic datasets of 32 raw leachate and 45 solid waste samples in 22 municipal landfills of China. The antibiotic resistome, antibiotic-resistant bacteria and contaminant-degrading bacteria were explored, and were then compared with other environmental types. Results showed that the antibiotic resistome in landfills contained 1,403 ARG subtypes, with the total abundance over the levels in natural environments and reaching the levels in human feces and sewage. Therein, 49 subtypes were listed as top priority ARGs for future surveillance based on the criteria of enrichment in landfills, mobilizable and present in pathogens. By comparing to those in less contaminated river environments, we elucidated an enrichment of antibiotic-resistant bacteria with contaminant-degrading potentials in landfills. Bacteria in Pseudomonadaceae, Moraxellaceae, Xanthomonadaceae and Enterobacteriaceae deserved the most concerns since 72.2 % of ARG hosts were classified to them. Klebsiella pneumoniae, Acinetobacter nosocomialis and Escherichia coli were abundant multidrug-resistant pathogenic species in raw leachate (∼10.2 % of total microbiomes), but they rarely carried contaminant-degradation genes. Notably, several bacterial genera belonging to Pseudomonadaceae had the most antibiotic-resistant, pathogenic, and contaminant-degrading potentials than other bacteria. Overall, the findings highlight environmental selection for contaminant-degrading antibiotic-resistant pathogens, and provide significant insights into AMR risks in municipal landfills.202539729867
6865100.9998A metagenomic analysis framework for characterization of antibiotic resistomes in river environment: Application to an urban river in Beijing. River is considered generally as a natural reservoir of antibiotic resistance genes (ARGs) in environments. For the prevention and control of ARG risks, it is critical to comprehensively characterize the antibiotic resistomes and their associations in riverine systems. In this study, we proposed a metagenomic framework for identifying antibiotic resistomes in river sediments from multiple categories, including ARG potential, ARG hosts, pathogenicity potential, co-selection potential and gene transfer potential, and applied it to understand the presence, hosts, and co-occurrence of ARGs in the sediments of an urban river in Beijing. Results showed that a total of 203 ARG subtypes belonging to 21 ARG types were detected in the river sediments with an abundance range of 107.7-1004.1×/Gb, dominated by multidrug, macrolide-lincosamide-streptogramin, bacitracin, quinolone and sulfonamide resistance genes. Host-tracking analysis identified Dechloromonas, Pseudoxanthomonas, Arenimonas, Lysobacter and Pseudomonas as the major hosts of ARGs. A number of ARG-carrying contigs (ACCs) were annotated as fragments of pathogenic bacteria and carried multiple multidrug-ARGs. In addition, various biocide/metal resistance genes (B/MRGs) and mobile genetic elements (MGEs), including prophages, plasmids, integrons and transposons, were detected in the river sediments. More importantly, the co-occurrence analysis via ACCs showed a strong association of ARGs with B/MRGs and MGEs, indicating high potential of co-selection and active horizontal transmission for ARGs in the river environment, likely driven by the frequent impact of anthropogenic activities in that area.201930453138
6868110.9998Rare 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
6846120.9998Antibiotic resistance genes in an urban river as impacted by bacterial community and physicochemical parameters. Antibiotic resistance genes (ARGs) in urban rivers are a serious public health concern in regions with poorly planned, rapid development. To gain insights into the predominant factors affecting the fate of ARGs in a highly polluted urban river in eastern China, a total of 285 ARGs, microbial communities, and 20 physicochemical parameters were analyzed for 17 sites. A total of 258 unique ARGs were detected using high-throughput qPCR, and the absolute abundance of total ARGs was positively correlated with total organic carbon and total dissolved nitrogen concentrations (P < 0.01). ARG abundance and diversity were greatly altered by microbial community structure. Variation partitioning analysis showed that the combined effects of multiple factors contributed to the profile and dissemination of ARGs, and variation of microbial communities was the major factor affecting the distribution of ARGs. The disparate distribution of some bacteria, including Bacteroides from mammalian gastrointestinal flora, Burkholderia from zoonotic infectious diseases, and Zoogloea from wastewater treatment, indicates that the urban river was strongly influenced by point-source pollution. Results imply that microbial community shifts caused by changes in water quality may lead to the spread of ARGs, and point-source pollution in urban rivers requires greater attention to control the transfer of ARGs between environmental bacteria and pathogens.201728864929
6863130.9998Prevalence, source and risk of antibiotic resistance genes in the sediments of Lake Tai (China) deciphered by metagenomic assembly: A comparison with other global lakes. Lakes are one of the natural reservoirs of antibiotic resistance genes (ARGs) in environments. Long retention times in lakes potentially allow ARGs to persist and may create increased opportunities for the emergence of resistant pathogens. In this study, we investigated the prevalence, source and dissemination risk of ARGs in the sediments of a typical urban lake, Lake Tai (China) which has been a drastic example of water pollution with eutrophication in the world due to its proliferated cyanobacterial blooms. High-throughput profilings of ARGs in the sediments of Lake Tai were characterized with metagenomic assembly, and were compared with those in other global lakes from Australia, Canada, Indonesia, Rwanda and the United States of America. The hosts of ARGs in the sediments of Lake Tai were explored based on the taxonomic annotation of ARG-carrying contigs and network analysis, and a novel recently-discovered crAssphage was employed for source tracking of resistance bacteria. Meanwhile, the potential resistome risk was identified by projecting the co-occurrence of acquired ARGs, mobile genetic elements (MGEs) and human bacterial pathogens into a three-dimensional exposure space. Results showed 321 ARG subtypes belonging to 21 ARG types were detected in the sediments of Lake Tai, dominated by multidrug, macrolide-lincosamide-streptogramin, bacitracin, quinolone, mupirocin and trimethoprim resistance genes. Relatively, the ARG levels in the sediments of Lake Tai were significantly higher than those in other global lakes. Source tracking showed the coverages of detected crAssphage in the sediments of Lake Tai were positively correlated with the total ARG coverage, suggesting the contribution of human fecal contamination to the prevalence of ARGs in this lake. It should be noted that the co-occurrence ratio of ARGs, MGEs and human pathogens in the sediments of Lake Tai was higher than that in other global lakes, likely indicating a higher risk for the resistance dissemination in the China's third largest freshwater lake.201930928850
6883140.9998Metagenomic insights into the profile of antibiotic resistomes in sediments of aquaculture wastewater treatment system. To meet the rapidly growing global demand for aquaculture products, large amounts of antibiotics were used in aquaculture, which might accelerate the evolution of antibiotic-resistant bacteria (ARB) and the propagation of antibiotic genes (ARGs). In our research, we revealed the ARGs profiles, their co-occurrence with mobile genetic elements (MGEs), and potential hosts in sediments of a crab pond wastewater purification system based on metagenomic analysis. The residual antibiotic seems to increase the propagation of ARGs in the crab pond, but there was no clear relationship between a given antibiotic type and the corresponding resistance genes. The effect of aquaculture on sediment was not as profound as that of other anthropogentic activities, but increased the relative abundance of sulfonamide resistance gene. A higher abundance of MGEs, especially plasmid, increased the potential ARGs dissemination risk in crab and purification ponds. Multidrug and sulfonamide resistance genes had greater potential to transfer because they were more frequently carried by MGEs. The horizontal gene transfer was likely to occur among a variety of microorganisms, and various ARGs hosts including Pseudomonas, Acinetobacter, Escherichia, and Klebsiella were identified. Bacterial community influenced the composition of ARG hosts, and Proteobacteria was the predominant hosts. Overall, our study provides novel insights into the environmental risk of ARGs in sediments of aquaculture wastewater treatment system.202234963542
6867150.9998Comparative analysis of characteristics of antibiotic resistomes between Arctic soils and representative contaminated samples using metagenomic approaches. Antibiotic resistance is one of the most concerned global health issues. However, comprehensive profiles of antibiotic resistance genes (ARGs) in various environmental settings are still needed to address modern antibiotic resistome. Here, Arctic soils and representative contaminated samples from ARG pollution sources were analyzed using metagenomic approaches. The diversity and abundance of ARGs in Arctic soils were significantly lower than those in contaminated samples (p < 0.01). ARG profiles in Arctic soils were featured with the dominance of vanF, ceoB, and bacA related to multidrug and bacitracin, whereas those from ARG pollution sources were characterized by prevalent resistance to anthropogenic antibiotics such as sulfonamides, tetracyclines, and beta-lactams. Mobile genetic elements (MGEs) were found in all samples, and their abundance and relatedness to ARGs were both lower in Arctic soils than in polluted samples. Significant relationships between bacterial communities and ARGs were observed (p < 0.01). Cultural bacteria in Arctic soils had clinically-concerned resistance to erythromycin, vancomycin, ampicillin, etc., but ARGs relevant to those antibiotics were undetectable in their genomes. Our results suggested that Arctic environment could be an important reservoir of novel ARGs, and antibiotic stresses could cause ARG pollution via horizontal gene transfer and enrichment of resistant bacteria.202438452676
6882160.9998Deciphering the mobility and bacterial hosts of antibiotic resistance genes under antibiotic selection pressure by metagenomic assembly and binning approaches. The presence of antibiotics can exert significant selection pressure on the emergence and spread of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). However, co-selection effects for ARGs, the mobility of ARGs and the identification of ARG hosts under high antibiotic selection pressures are poorly understood. Here, metagenomic assembly and binning approaches were used to comprehensively decipher the prevalence of ARGs and their potential mobility and hosts in activated sludge reactors treating antibiotic production wastewater. We found the abundance of different ARG types in antibiotic treatments varied greatly and certain antibiotic pressure promoted the co-selection for the non-corresponding types of ARGs. Antibiotic selection pressures significantly increased the abundance and proportions of ARGs mediated by plasmids (57.9%), which were more prevalent than those encoded in chromosomes (19.2%). The results indicated that plasmids and chromosomes had a tendency to carry different types of ARGs. Moreover, higher co-occurrence frequency of ARGs and MGEs revealed that antibiotics enhanced the mobility potential of ARGs mediated by both plasmids and integrative and conjugative elements. Among the 689 metagenome-assembled genomes (MAGs) with high estimated quality, 119 MAGs assigning to nine bacterial phyla were identified as the ARG hosts and 33 MAGs exhibited possible multi-resistance to antibiotics. Some ARG types tended to be carried by certain bacteria (e.g. bacitracin resistance genes carried by the family Burkholderiaceae) and thus showed a pronounced host-specific pattern. This study enhances the understanding of the mobility and hosts of ARGs and provides important insights into the risk assessment and management of antibiotic resistance.202032871290
6866170.9998Deciphering the antibiotic resistome in stratified source water reservoirs in China: Distribution, risk, and ecological drive. The proliferation and dissemination of antibiotic resistance genes (ARGs) in source water reservoirs may pose a threat to human health. This study investigated the antibiotic resistance in stratified reservoirs in China across different seasons and spatial locations. In total, 120 ARG subtypes belonging to 15 ARG types were detected with an abundance ranging from 171.06 to 793.71 × /Gb. Multidrug, tetracycline, aminoglycoside, and bacitracin resistance genes were dominant in the reservoirs. The abundance and transfer potential of ARGs were notably higher, especially during the stratified period, with markedly elevated levels in the bottom layer compared to the surface layer. Metagenomic assembly yielded 1357 ARG-carrying contigs, belonging to 83 resistant bacterial species, of which 13 were identified as human pathogen bacteria (HPB). HPB hosts (Sphingomonas sp., Burkholderiales sp., and Ralstonia sp., etc.) were super carriers of ARGs. Genes including ompR, bacA, golS, and ugd carried on HPB plasmids exhibited higher abundance in the water, warranting attention to the risk of resistance transmission. Environmental pressures have caused a shift in the assembly mechanism of ARGs, transitioning from a random process in surface water to a deterministic process in bottom water. The results of this study will deepen people's understanding of the ARG risk in stratified reservoirs.202539673943
6858180.9998Antibiotic resistance genes risks in relation to host pathogenicity and mobility in a typical hospital wastewater treatment process. Hospital wastewaters (HWWs) serve as critical reservoirs for disseminating antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). However, the dynamics and noteworthy shifts of ARGs and their associated pathogenicity, mobility, and resistome risks during HWWs treatment processes remain poorly understood. Utilizing metagenomic sequencing and assembly, we identified 817 ARG subtypes conferring resistance to 20 classes of antibiotics across 18 HWW samples from influent to effluent. Genes encoding resistance to multidrug, aminoglycoside and beta_lactam were the most prevalent ARG types, reflecting patterns observed in clinical settings. On-site treatment efforts decreased the relative abundance of ARGs by 77.4% from influent to secondary sedimentation, whereas chlorine disinfection significantly increased their abundance in the final effluent. Deterministic processes primarily drove the taxonomic assembly, with Proteobacteria being the most abundant phylum and serving as the primary host for 15 ARG types. Contig-based analysis further revealed 114 pathogenic ARB, with Escherichia coli, Pseudomonas alcaligenes, and Pseudomonas aeruginosa exhibiting multidrug-resistant. The contributions of host bacteria and pathogenic ARB varied throughout wastewater treatment. In addition, 7.10%-31.0 % ARGs were flanked by mobile genetic elements (MGEs), predominantly mediated by transposase (74.1%). Notably, tnpA exhibited the highest potential for ARG dissemination, frequently co-occurring with beta-lactam resistance genes (35.2%). Considering ARG profiles, pathogenic hosts, and transferability, raw influent exhibited the highest antibiotic resistome risk index (ARRI), followed by the final effluent. Chlorine disinfection exacerbated resistome risks by inducing potential pathogenic ARB and mobile ARGs, posing threats to the receiving environment. This study delineates ARG occurrence patterns, highlights mechanisms of ARG carriage and horizontal gene transfer, and provides insights for assessing resistance risks and prioritizing interventions in clinical settings.202438964571
6850190.9998Fate of high-risk antibiotic resistance genes in large-scale aquaculture sediments: Geographical differentiation and corresponding drivers. Antibiotic resistance genes (ARGs), emerging environmental contaminants, have become challenges of public health security. However, the distribution and drivers of ARGs, especially high-risk ARGs, in large-scale aquaculture sediments remain unknown. Here, we collected sediment samples from 40 crayfish ponds in seven main crayfish culture provinces in China and then investigated the distribution and risk of ARGs based on high-throughput sequencing and quantitative PCR techniques. Our results suggested that aquaculture sediment was potential reservoir of ARGs and the abundance of aadA-02 was the highest. High-risk ARG (floR) was also prevalent in the sediment and was the most abundant in Jiangsu Province, where opportunistic pathogens were also enriched. The abundance of floR was positively correlated with different environmental factors, such as total phosphorus in water and total carbon in sediment. In addition, Mycobacterium sp., opportunistic pathogenic bacteria, might be potential host for floR. Furthermore, the potential propagation pathway of ARGs was from sediment to crayfish gut, and Bacteroidetes and Proteobacteria might be the main bacterial groups responsible for the proliferation of ARGs. Generally, our results illustrate that pond sediment may be an ARG reservoir of aquatic animals. Meanwhile, our study helps develop valuable strategies for accessing risks and managing ARGs.202337714353