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638100.9412Occurrence and distribution of antibiotic resistance genes in Elymus nutans silage from different altitudes on the Qinghai-Tibetan Plateau. INTRODUCTION: Antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) have attracted more attentions in fermented feed recently. However, little information is available on the occurrence and distribution of ARGs in ensiled forages in the alpine region of the Qinghai-Tibetan plateau (QTP) with an extremely harsh environment. METHODS: The study investigated the distribution and spread mechanism of ARB and ARGs in Elymus nutans silage along 2600 m (low), 3600 m (medium) and 4600 m (high) altitude in the QTP. RESULTS: The major ARG types in Elymus nutans silage were multidrug, aminoglycoside, bacitracin, beta-lactam and polymyxin, while tnpA and IS91 were the dominant mobile genetic elements (MGEs) subtypes in the Elymus nutans silage. The dominant ARGs were mainly carried by Pantoea, Enterobacter, Serratia, and Lelliottia. Although altitudinal gradient had no influence on the diversity or abundance of other ARGs and MGEs in the Elymus nutans silage (p > 0.05), the network co-occurrence patterns among ARGs, MGEs, and bacteria in high-altitude silage were more complex than that in low- and medium-altitude silages. The dominant clinical ARGs in the alpine silage were bacA and acrF, and the abundance of clinical ARGs decreased with prolonged fermentation time. DISCUSSION: This study provides important data on the status of ARGs in ensiled forage from the alpine region of the QTP.202540458713
764210.9361Metagenomics insights into the effects of lactic acid bacteria inoculation on the biological reduction of antibiotic resistance genes in alfalfa silage. Antibiotic resistance genes (ARGs) are a new type of pollutant and pose major threats to public health. However, the distribution and transmission risk of ARGs in alfalfa silage as the main forage for ruminants have not been studied. This study first deciphered the effects of Lactobacillus plantarum MTD/1 or Lactobacillus buchneri 40788 inoculations on distribution and transmission mechanism of ARGs in alfalfa silage by metagenomics. Results showed that multidrug and bacitracin resistance genes were the dominant ARGs in ensiled alfalfa. The natural ensiling process increased the abundances of bacitracin, beta_lactam, and aminoglycoside in alfalfa silage with 30% DM, and vancomycin in alfalfa silage with 40% DM. Meanwhile, prolonged wilting increased ARG enrichment in fresh alfalfa. Interestingly, alfalfa silage inoculated with L. plantarum MTD/1 or L. buchneri 40788 reduced the abundances of total ARG, and multidrug, MLS, vancomycin, aminoglycoside, tetracycline, and fosmidomycin resistance genes by reductions of the host bacteria and the enrichment of ARGs located in the plasmid. The hosts of ARG in alfalfa silage were mainly derived from harmful bacteria or pathogens, and some of the clinical ARGs were observed in alfalfa silage. Basically, the combined effect of microbes, MGEs, and fermentation quality was the major driver of ARG transfer and dissemination in microecosystem of ensiling, where the microbes appeared to be the crucial factor. In summary, inoculation with the present lactic acid bacteria could reduce ARG abundance in ensiled alfalfa, and a better effect was observed in L. plantarum-treated silage than in L. buchneri treated silage.202336444055
716720.9356Occurrence and distribution of antibiotic pollution and antibiotic resistance genes in seagrass meadow sediments based on metagenomics. Seagrass meadows are one of the most important coastal ecosystems that provide essential ecological and economic services. The contamination levels of antibiotic and antibiotic resistance genes (ARGs) in coastal ecosystems are severely elevated owing to anthropogenic disturbances, such as terrestrial input, aquaculture effluent, and sewage discharge. However, few studies have focused on the occurrence and distribution of antibiotics and their corresponding ARGs in this habitat. Thus, we investigated the antibiotic and ARGs profiles, microbial communities, and ARG-carrying host bacteria in typical seagrass meadow sediments collected from Swan Lake, Caofeidian shoal harbor, Qingdao Bay, and Sishili Bay in the Bohai Sea and northern Yellow Sea. The total concentrations of 30 detected antibiotics ranged from 99.35 to 478.02 μg/kg, tetracyclines were more prevalent than other antibiotics. Metagenomic analyses showed that 342 ARG subtypes associated with 22 ARG types were identified in the seagrass meadow sediments. Multidrug resistance genes and RanA were the most dominant ARG types and subtypes, respectively. Co-occurrence network analysis revealed that Halioglobus, Zeaxanthinibacter, and Aureitalea may be potential hosts at the genus level, and the relative abundances of these bacteria were higher in Sishili Bay than those in other areas. This study provided important insights into the pollution status of antibiotics and ARGs in typical seagrass meadow sediments. Effective management should be performed to control the potential ecological health risks in seagrass meadow ecosystems.202438782270
812630.9346Antiallergic drugs drive the alteration of microbial community and antibiotic resistome in surface waters: A metagenomic perspective. Antiallergic drugs (AADs) are emerging contaminants of global concern due to their environmental persistence and potential ecological impacts. This study investigated the effects of seven AADs (chlorpheniramine, diphenhydramine, cetirizine, loratadine, desloratadine, sodium cromoglicate and calcium gluconate) at environmentally relevant concentrations on antibiotic resistome and bacterial community structures in water using microcosm experiments and metagenomic sequencing. The results showed that AADs increased the abundance of antibiotic-resistant bacteria (ARB) by 1.24- to 7.78-fold. Community structure shifts indicated that chlorpheniramine, diphenhydramine, and cetirizine promoted Actinobacteria (e.g., Aurantimicrobium), while the other four AADs favored Proteobacteria (e.g., Limnohabitans). AADs also significantly altered the relative abundance of antibiotic resistance genes (ARGs), with Actinobacteria and Proteobacteria identified as key ARB components and potential hosts of ARGs (e.g., evgS, mtrA, RanA). Host analysis showed ARGs were primarily carried by Actinobacteria (e.g., Aurantimicrobium) under chlorpheniramine, diphenhydramine, and cetirizine exposure, but by Proteobacteria (e.g., Limnohabitans) under the other four AADs. Furthermore, AADs facilitated the horizontal transfer of ARGs (e.g., evgS) within microbial communities, contributing to antibiotic resistance dissemination. This study highlights the ecological risks of AADs in promoting antibiotic resistance spread and provides new insights into their impact on microbial communities and resistome dynamics in aquatic environments.202540570627
679340.9341Interplays between cyanobacterial blooms and antibiotic resistance genes. Cyanobacterial harmful algal blooms (cyanoHABs), which are a form of microbial dysbiosis in freshwater environments, are an emerging environmental and public health concern. Additionally, the freshwater environment serves as a reservoir of antibiotic resistance genes (ARGs), which pose a risk of transmission during microbial dysbiosis, such as cyanoHABs. However, the interactions between potential synergistic pollutants, cyanoHABs, and ARGs remain poorly understood. During cyanoHABs, Microcystis and high microcystin levels were dominant in all the nine regions of the river sampled. The resistome, mobilome, and microbiome were interrelated and linked to the physicochemical properties of freshwater. Planktothrix and Pseudanabaena competed with Actinobacteriota and Proteobacteria during cyanoHABs. Forty two ARG carriers were identified, most of which belonged to Actinobacteriota and Proteobacteria. ARG carriers showed a strong correlation with ARGs density, which decreased with the severity of cyanoHAB. Although ARGs decreased due to a reduction of ARG carriers during cyanoHABs, mobile gene elements (MGEs) and virulence factors (VFs) genes increased. We explored the relationship between cyanoHABs and ARGs for potential synergistic interaction. Our findings demonstrated that cyanobacteria compete with freshwater commensal bacteria such as Actinobacteriota and Proteobacteria, which carry ARGs in freshwater, resulting in a reduction of ARGs levels. Moreover, cyanoHABs generate biotic and abiotic stress in the freshwater microbiome, which may lead to an increase in MGEs and VFs. Exploration of the intricate interplays between microbiome, resistome, mobilome, and pathobiome during cyanoHABs not only revealed that the mechanisms underlying the dynamics of microbial dysbiosis but also emphasizes the need to prioritize the prevention of microbial dysbiosis in the risk management of ARGs.202337897871
638350.9338Metagenomic analysis of microbiological risk in bioaerosols during biowaste valorization using Musca domestica. Bioconversion using insects has gradually become a promising technology for biowaste management and protein production. However, knowledge about microbiological risk of insect related bioaerosols is sparse and conventional methods failed to provide higher resolved information of environmental microbe. In this study, a metagenomic analysis including microorganisms, antibiotic resistance genes (ARGs), virulence factor genes (VFGs), mobile gene elements (MGEs), and endotoxin distribution in bioaerosols during biowaste conversion via Musca domestica revealed that bioaerosols in Fly rearing room possess the highest ARGs abundances and MGEs diversity. Through a metagenome-assembled genomes (MAGs)-based pipeline, compelling evidence of ARGs/VFGs host assignment and ARG-VFG co-occurrence pattern were provided from metagenomic perspective. Bioaerosols in Bioconversion and Maggot separation zone were identified to own high density of MAGs carrying both ARGs and VFGs. Bacteria in Proteobacteria, Actinobacteriota, and Firmicutes phyla were predominate hosts of ARGs and VFGs. Multidrug-Motility, Multidrug-Adherence, and Beta lactam-Motility pairs were the most common ARG-VFG co-occurrence pattern in this study. Results obtained are of great significance for microbiological risk assessment during housefly biowaste conversion process.202336681377
700460.9327Sheep and rapeseed cake manure promote antibiotic resistome in agricultural soil. The application of manure in agriculture caused the emergence and spread of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in soil environments. However, the co-occurrence pattern and host diversity of ARGs and MGEs in soils amended with animal and green manures remains unclear. In this study, metagenomic assembly and binning techniques were employed to comprehensively explore the effects of sheep manure and green manure on soil microbiome, antibiotic resistomes, and ARG hosts. Both rapeseed cake manure and sheep manure increased the abundance and diversity of ARGs, with sheep manure particularly enhancing the abundance of ARGs conferring resistant to multidrug, quinolone, rifampicin, and macrolide-lincosamide-streptogramin (MLSB). Mobile genetic elements (MGEs), such as plasmids, transposases, and integrases, preferentially enhanced the potential mobility of some ARGs subtypes (i.e. sul2, aadA, qacH, and folp), facilitating the spread of ARGs. Additionally, sheep manure reshaped the bacterial community structure and composition as well as ARG hosts, some opportunistic pathogens (i.e. Staphylococcus, Streptococcus, and Pantoea) acquired antibiotic resistance and remained recalcitrant. It is concluded that rapeseed cake manure and sheep manure increased the co-occurrence of ARGs and MGEs, enriched the potential ARG hosts, and promoted the dissemination of ARGs in agricultural soils.202540633350
693770.9327Differential responses of bacterial and archaeal communities to biodegradable and non-biodegradable microplastics in river. Microplastics are widespread environmental pollutants that pose risks to ecosystems, yet their effects on bacterial and archaeal communities in aquatic ecosystems remain understudied. In this study, we performed a 14-day microcosm experiment combined with metagenomic sequencing to compare bacterial and archaeal responses to a biodegradable microplastic (polylactic acid, PLA) and a non-biodegradable microplastic (polyvinyl chloride, PVC). Microplastics selectively enriched distinct microbial assemblages, with Pseudomonadota and Euryarchaeota identified as the dominant bacterial and archaeal phyla, accounting for 67.83 % and 15.95 %, respectively. Archaeal community in surrounding water were more sensitive to colonization time than bacterial community. Compared to the surrounding water, the plastisphere displayed simpler and more loosely connected microbial networks. Notably, co-occurrence networks of both bacteria and archaea in the PVC plastisphere were predominantly shaped by symbiotic interactions. Both bacteria and archaea carried diverse antibiotic resistance genes (ARGs), but PLS-PM indicated that bacteria were the primary drivers of ARG dissemination (path coefficient = 0.952). While the PVC plastisphere showed higher ARG abundance than the PLA plastisphere, elevated intI1 expression in the PLA plastisphere suggests a potentially greater risk of ARG dissemination associated with PLA microplastics. These findings reveal the distinct effects of PLA and PVC microplastics on microbial communities and highlight the role of microplastics in ARG dissemination, emphasizing their ecological risks in aquatic ecosystems.202540712359
716980.9326Distributions of pathogenic bacteria, antibiotic resistance genes, and virulence factors in pig farms in China. The abundance of antibiotic resistance genes (ARGs) in pig feces can lead to their dissemination in the pig farm environment, posing a serious risk to human health through potential exposure and transmission. However, the extent of microbial contamination in pig farms, including ARGs, virulence factor genes (VFGs), mobile genetic elements (MGEs), and human bacterial pathogens (HBPs), is still largely unknown. In this study, metagenomics was employed to identify the composition and characteristics of microorganism communities, ARGs, VFGs, MGEs and HBPs in pig farm environments from seven different regions of China. The results showed that there were significant differences in the composition of microorganisms and Firmicutes, Bacteroides, Proteobacteriahe Spirochaetes were the dominant phyla in the pig farm environment. The abundance and composition of ARGs, VFGs, MGEs and HBPs varied significantly in pig farm environments in different regions, with the abundance in Fujian being significantly higher than that in other regions. In total, 216 ARGs, 479 VFGs, 143 MGEs and 78 HBPs were identified across all pig feces, soil, and wastewater samples. The most prominent ARGs were those related to tetracycline, aminoglycoside, and MLS resistance. Escherichia coli, Arcobacter cryaerophilus, Corynebacterium xerosis, Aerococcus viridans, and Collinsella aerofaciens were the most commonly found HBPs in the pig farm environment. Procrustes analysis and Mantel test results showed a strong correlation between ARGs and HBPs, VFGs and HBPs, and ARGs and VFGs. ARGs were mainly harbored by E. coli, Klebsiella pneumoniae, and Enterococcus faecalis in the pig farm environments. The random forest model indicated that the presence of MGEs (intI1, IS91, and tnpA) was significantly correlated with the total abundance of resistance genes, which can be utilized as an important indicator for measuring resistance genes. The study establishes a foundational understanding of the prevalence and diversity of ARGs, VFGs, and HBPs in pig farm environments, aiding in the development of effective management strategies to mitigate ecological and public health risks.202540609272
811190.9325Effect of alkaline-thermal pretreatment on biodegradable plastics degradation and dissemination of antibiotic resistance genes in co-compost system. Biodegradable plastics (BDPs) are an eco-friendly alternative to traditional plastics in organic waste, but their microbial degradation and impact on antibiotic resistance genes (ARGs) transmission during co-composting remain poorly understood. This study examines how alkaline-thermal pretreatment enhances BDPs degradation and influences the fate of ARGs and mobile genetic elements (MGEs) in co-composting. Pretreatment with 0.1 mol/L NaOH at 100℃ for 40 minutes increased the surface roughness and hydrophilicity of BDPs while reducing their molecular weight and thermal stability. Incorporating pretreated BDPs film (8 g/kg-TS) into the compost reduced the molecular weight of the BDPs by 59.70 % during the maturation stage, facilitating compost heating and prolonging the thermophilic stage. However, incomplete degradation of BDPs releases numerous smaller-sized microplastics, which can act as carriers for microorganisms, facilitating the dissemination of ARGs across environments and posing significant ecological and public health risks. Metagenomic analysis revealed that pretreatment enriched plastic-degrading bacteria, such as Thermobifida fusca, on BDPs surfaces and accelerated microbial plastic degradation during the thermophilic stage, but also increased ARGs abundance. Although pretreatment significantly reduced MGEs abundance (tnpA, IS19), the risk of ARGs dissemination remained. Three plastic-degrading bacteria (Pigmentiphaga sp002188465, Bacillus clausii, and Bacillus altitudinis) were identified as ARGs hosts, underscoring the need to address the risk of horizontal gene transfer of ARGs associated with pretreatment in organic waste management.202539970645
7170100.9320Effect of cattle farm exposure on oropharyngeal and gut microbial communities and antibiotic resistance genes in workers. Livestock farms are recognized as the main sources of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) with potential implications for human health. In this study, we systematically analyzed microbiome composition, distribution of ARGs and mobile genetic elements (MGEs) in the oropharynx and gut of workers in cattle farms and surrounding villagers, cattle feces and farm air, and the relationship of microbial communities among farm air, cattle feces and farmworkers (oropharynx and gut). Exposure to the farm environment may have remodeled farmworkers' oropharynx and gut microbiota, with reduced microbial diversity (P < 0.05) and enrichment of some opportunistic pathogenic bacteria like Shigella, Streptococcus, and Neisseria in the oropharynx. Meanwhile, compared with villagers, ARG abundance in oropharynx of farmworkers increased significantly (P < 0.05), but, no significant difference in gut (P > 0.05). Microbial composition and ARG profile in farmworkers might be influenced by working time and work type, ARG abundance in farmworkers' gut was positively correlated with working time (P < 0.01), and higher ARG abundance was found in the oropharynx of drovers. The network analysis revealed that 4 MGEs (tnpA-01, tnpA-04, Tp614, and IS613), 5 phyla (e.g. Bacteroidetes, Fusobacteria, and TM7), and 6 genera were significantly associated with 37 ARGs (ρ > 0.6, P < 0.01). Overall, our results indicated that farm exposure may have affected the microbial composition and increased ARG abundance of farmworkers. Transmission of some ARGs may have occurred among the environment, animals and humans via host bacteria, which might pose a potential threat to human health.202234600986
6967110.9320Effects of Pyroligneous Acid on Diversity and Dynamics of Antibiotic Resistance Genes in Alfalfa Silage. Antibiotic resistance genes (ARGs) are recognized as contaminants due to their potential risk for human and environment. The aim of the present study is to investigate the effects of pyroligneous acid (PA), a waste of biochar production, on fermentation characteristics, diversity, and dynamics of ARGs during ensiling of alfalfa using metagenomic analysis. The results indicated that PA decreased (P < 0.05) dry matter loss, pH value, gas production, coliform bacteria count, protease activity, and nonprotein-N, ammonia-N, and butyric acid contents and increased (P < 0.05) lactic acid content during ensiling. During fermentation, Bacteria, Firmicutes, and Lactobacillus were the most abundant at kingdom, phylum, and genus levels, respectively. Pyroligneous acid reduced the relative abundance of Bacteria and Firmicutes and increased that of Lactobacillus. The detected ARGs belonged to 36 drug classes, including mainly macrolides, tetracycline, lincosamides, and phenicol. These types of ARGs decreased during fermentation and were further reduced by PA. These types of ARGs were positively correlated (P < 0.05) with fermentation parameters like pH value and ammonia-N content and with bacterial communities. At the genus level, the top several drug classes, including macrolide, tetracycline, lincosamide, phenicol, oxazolidinone, streptogramin, pleuromutilin, and glycopeptide, were positively correlated with Staphylococcus, Streptococcus, Listeria, Bacillus, Klebsiella, Clostridium, and Enterobacter, the potential hosts of ARGs. Overall, ARGs in alfalfa silage were abundant and were influenced by the fermentation parameters and microbial community composition. Ensiling could be a feasible way to mitigate ARGs in forages. The addition of PA could not only improve fermentation quality but also reduce ARG pollution of alfalfa silage. IMPORTANCE Antibiotic resistance genes (ARGs) are considered environmental pollutants posing a potential human health risk. Silage is an important and traditional feed, mainly for ruminants. ARGs in silages might influence the diversity and distribution of ARGs in animal intestinal and feces and then the manure and the manured soil. However, the diversity and dynamics of ARGs in silage during fermentation are still unknown. We ensiled alfalfa, one of the most widely used forages, with or without pyroligneous acid (PA), which was proved to have the ability to reduce ARGs in soils. The results showed that ARGs in alfalfa silage were abundant and were influenced by the fermentation parameters and microbial community. The majority of ARGs in alfalfa silage reduced during fermentation. The addition of PA could improve silage quality and reduce ARG pollution in alfalfa silage. This study can provide useful information for understanding and controlling ARG pollution in animal production.202235862964
7168120.9319Insights into microbial contamination in multi-type manure-amended soils: The profile of human bacterial pathogens, virulence factor genes and antibiotic resistance genes. Concerns regarding biological risk in environment have garnered increasing attention. Manure has been believed to be a significant source of antibiotic resistance genes (ARGs) in agricultural soil. Nevertheless, the profile of microbial contamination including ARGs, virulence factor genes (VFGs) and human bacterial pathogens (HBPs) in different manure-amended soils remain largely unknown. Here, we conducted the systematic metagenome-based study to explore changes in resistome, VFGs and HBPs in soils treated by frequently-used manures. The results revealed that many manure-borne ARGs, VFGs, and HBPs could be spreaded into soils, and their diversity and abundance were significantly different among chemical fertilizer, pig manure, chicken manure, cow dung and silkworm excrement application. A total of 157 potential HBPs accounting about 1.33% of total bacteria were detected. The main ARGs transferred from manures to soil conferred resistance to vancomycin and macrolide-lincosamide-streptogramin. The series analysis revealed positive co-occurrence patterns of ARGs-HBPs, VFGs-HBPs and ARGs-VFGs. Microbial contamination were more serious in pig manure and silkworm excrement sample than in the other samples, implying the usage of these two manures increased the risk of HBPs and dissemination of ARGs. This study confirmed the prevalence and discrepancy of resistome, VFGs and HBPs in different manure-amended soils.202235728317
7643130.9319Heterofermentative Lentilactobacillus buchneri and low dry matter reduce high-risk antibiotic resistance genes in corn silage by regulating pathogens and mobile genetic element. The study of antibiotic resistance in the silage microbiome has attracted initial attention. However, the influences of lactic acid bacteria inoculants and dry matter (DM) content on antibiotic resistance genes (ARGs) reduction in whole-plant corn silage remain poorly studied. This study accessed the ARGs' risk and transmission mechanism in whole-plant corn silage with different DM levels and treated with Lactiplantibacillus plantarum or Lentilactobacillus buchneri. The macrolide and tetracycline were the main ARGs in corn silage. The dominant species (Lent. buchneri and Lactobacillus acetotolerans) were the main ARGs carriers in whole-plant corn silage. The application of Lent. buchneri increased total ARGs abundance regardless of corn DM. Whole-plant corn silage with 30 % DM reduced the abundances of integrase and plasmid compared with 40 % DM. The correlation and structural equation model analysis demonstrated that bacterial community succession, resulting from changes in DM content, was the primary driving factor influencing the ARGs distribution in whole-plant corn silage. Interestingly, whole-plant corn silage inoculated with Lent. buchneri reduced abundances of high-risk ARGs (mdtG, mepA, tetM, mecA, vatE and tetW) by regulating pathogens (Escherichia coli), mobile genetic elements (MGEs) genes (IS3 and IS1182), and this effect was more pronounced at 30 % DM level. In summary, although whole-plant corn silage inoculated with Lent. buchneri increased the total ARGs abundance at both DM levels, it decreased the abundance of high-risk ARGs by reducing the abundances of the pathogens and MGEs, and this effect was more noticeable at 30 % DM level.202439241365
6821140.9319Mangrove plastisphere as a hotspot for high-risk antibiotic resistance genes and pathogens. Microplastics (MPs) are critical vectors for the dissemination of antibiotic resistance genes (ARGs); however, the prevalence and ecological risks of high-risk ARGs in mangrove ecosystems-globally vital yet understudied coastal habitats-remain poorly understood. To address this gap, this study investigated polyethylene, polystyrene, and polyvinyl chloride incubated in mangrove sediments for one month, focusing on high-risk ARGs, virulence gene (VGs), and pathogenic antibiotic-resistant bacteria within the mangrove plastisphere. High-throughput PCR and metagenomic analyses revealed that high-risk ARGs, VGs, and mobile genetic elements (MGEs) were significantly enriched on MPs compared to surrounding sediments. Pathogenic bacteria and MGEs were also more abundant in the plastisphere, highlighting its role as a hotspot for ARG dispersal. Metagenome-assembled genome analysis identified Pseudomonas and Bacillus as key hosts for ARGs, MGEs, and VGs, particularly multidrug resistance genes, integrase genes, and adherence factors. Notably, polystyrene harbored the highest abundance of pathogenic bacteria carrying ARGs, MGEs, and VGs, and mangrove root exudates were found to amplify horizontal gene transfer on MPs, uncovering a previously overlooked mechanism driving antibiotic resistance in coastal ecosystems. These findings not only elucidate how MPs accelerate the spread of ARGs, but also underscore the urgent need for targeted mitigation strategies to address the adverse impacts microplastic pollution on human, animal, and environmental health.202540043931
7052150.9318Plastisphere enrich antibiotic resistance genes and potential pathogenic bacteria in sewage with pharmaceuticals. Microplastics (MPs) and pharmaceuticals are common emerging pollutants in sewage, and their coexistence may have more negative effects on the environments. This study chose tetracycline (TC), ampicillin (AMP) and triclosan (TCS) to investigate the responses of antibiotic resistance genes (ARGs) and microbial communities on different MPs (polyvinyl chloride (PVC), polyethylene (PE)) biofilms (plastisphere). The adsorption capacity of three pharmaceuticals on PVC and PE decreased in the order of AMP > TC > TCS. PE was more conducive to microbial attachment than PVC. MPs led to the increase of the total copies of ARGs and mobile genetic elements (MGEs) in the sewage. Importantly, multidrug ARGs and MGEs were enriched on plastisphere. Furthermore, the co-occurrence of TC and MPs led to higher risks of spreading ARGs and MGEs. In addition, potential pathogenic bacteria Legionella, Mycobacterium, Neisseria and Arcobacter were more abundant on plastisphere than those in sewage, and these bacteria might be the hosts for ARGs and MGEs. This study showed that plastisphere could be repositories of ARGs and MGEs in sewage and accumulated potential pathogenic bacteria.202133454495
6932160.9317Distribution of antibiotic resistance genes in soil amended using Azolla imbricata and its driving mechanisms. The floating aquatic plant of Azolla imbricata has an outstanding purification capability for polluted river water, and it is also employed to improve soil fertility. However, the occurrence and distribution of antibiotic resistance genes (ARGs) in soil amended using A.imbricata remain unclear. In the soil amendment with A. imbricata, heavy metals, antibiotics, transposase genes, ARGs, and bacterial communities in the soil were determined in this study. The results indicated that the diversity of bacteria and ARGs increased, while the diversity of ARGs decreased under the amendment using an appropriate amount of A. imbricata. The Firmicutes, Chloroflexi, Actinobacteria, and Cyanobacteria were the main host bacteria of ARGs. The vertical gene transfer of ARGs was weak, and the horizontal gene transfer became the dominant transfer pathway of ARGs. The amendment with A. imbricata altered the distribution of heavy metals, antibiotics, transposase genes, ARGs, and dominant bacteria. The amendment using A. imbricata promoted the degradation of antibiotics, decreased the concentrations of available heavy metals, and eliminated the abundance of ARGs and transposase genes. Our findings suggested a comprehensive effect of multiple stresses on the fate of ARGs in soil amended with A. imbricata, providing an insight into the distribution and propagation of ARGs in soil amended using plant residues.201931351286
7007170.9316Tracking resistomes, virulence genes, and bacterial pathogens in long-term manure-amended greenhouse soils. Organic manure has been implicated as an important source of antibiotic resistance genes (ARGs) in agricultural soils. However, the profiles of biocide resistance genes (BRGs), metal resistance genes (MRGs) and virulence genes (VGs) and their bacterial hosts in manure-amended soils remain largely unknown. Herein, a systematic metagenome-based survey was conducted to comprehensively explore the changes in resistomes, VGs and their bacterial hosts, mobile genetic elements (MGEs), and pathogenic bacteria in manure-amended greenhouse soils. Many manure-borne ARGs, BRGs, MRGs, VGs, and bacterial pathogens could be transferred into soils by applying manures, and their abundance and diversity were markedly positively correlated with greenhouse planting years (manure amendment years). The main ARGs transferred from manures to soils conferred resistance to tetracycline, aminoglycoside, and macrolide-lincosamide-streptogramin. Both statistical analysis and gene arrangements showed a good positive co-occurrence pattern of ARGs/BRGs/MRGs/VGs and MGEs. Furthermore, bacterial hosts of resistomes and VGs were significantly changed in the greenhouse soils in comparison with the field soils. Our findings confirmed the migration and dissemination of resistomes, VGs, and bacterial pathogens, and their accumulation and persistence were correlated with the continuous application of manures.202032298867
6939180.9315Field ponding water exacerbates the dissemination of manure-derived antibiotic resistance genes from paddy soil to surrounding waterbodies. Farmlands fertilized with livestock manure-derived amendments have become a hot topic in the dissemination of antibiotic resistance genes (ARGs). Field ponding water connects rice paddies with surrounding water bodies, such as reservoirs, rivers, and lakes. However, there is a knowledge gap in understanding whether and how manure-borne ARGs can be transferred from paddy soil into field ponding water. Our studies suggest that the manure-derived ARGs aadA1, bla1, catA1, cmlA1-01, cmx(A), ermB, mepA and tetPB-01 can easily be transferred into field ponding water from paddy soil. The bacterial phyla Crenarchaeota, Verrucomicrobia, Cyanobacteria, Choloroflexi, Acidobacteria, Firmicutes, Bacteroidetes, and Actinobacteria are potential hosts of ARGs. Opportunistic pathogens detected in both paddy soil and field ponding water showed robust correlations with ARGs. Network co-occurrence analysis showed that mobile genetic elements (MGEs) were strongly correlated with ARGs. Our findings highlight that manure-borne ARGs and antibiotic-resistant bacteria in paddy fields can conveniently disseminate to the surrounding waterbodies through field ponding water, posing a threat to public health. This study provides a new perspective for comprehensively assessing the risk posed by ARGs in paddy ecosystems.202337007487
8110190.9315Removal of chlortetracycline and antibiotic resistance genes in soil by earthworms (epigeic Eisenia fetida and endogeic Metaphire guillelmi). The impacts of two ecological earthworms on the removal of chlortetracycline (CTC, 0.5 and 15 mg kg(-1)) and antibiotic resistance genes (ARGs) in soil were explored through the soil column experiments. The findings showed that earthworm could significantly accelerate the degradation of CTC and its metabolites (ECTC) in soil (P < 0.05), with epigeic Eisenia fetida promoting degradation rapidly and endogeic Metaphire guillelmi exhibiting a slightly better elimination effect. Earthworms alleviated the abundances of tetR, tetD, tetPB, tetG, tetA, sul1, TnpA, ttgB and intI1 in soil, with the total relative abundances of ARGs decreasing by 35.0-44.2% in earthworm treatments at the 28th day of cultivation. High throughput sequencing results displayed that the structure of soil bacteria community was modified apparently with earthworm added, and some possible CTC degraders, Aeromonas, Flavobacterium and Luteolibacter, were promoted by two kinds of earthworms. Redundancy analysis demonstrated that the reduction of CTC residues, Actinobacteria, Acidobacteria and Gemmatimonadetes owing to earthworm stimulation was responsible for the removal of ARGs and intI1 in soil. Additionally, intI1 declined obviously in earthworm treatments, which could weaken the risk of horizontal transmission of ARGs. Therefore, earthworm could restore the CTC-contaminated soil via enhancing the removal of CTC, its metabolites and ARGs.202133798888