Effect of conjugative transfer of antibiotic resistance genes mediated by plasmids on the microecology of different intestinal segments. - Related Documents




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371401.0000Effect of conjugative transfer of antibiotic resistance genes mediated by plasmids on the microecology of different intestinal segments. INTRODUCTION: The conjugative transfer of antibiotic resistance genes (ARGs) mediated by plasmids occurred in different intestinal segments of mice was explored. METHODS: The location of ARG donor bacteria and ARGs was investigated by qPCR, flow cytometry, and small animal imaging. The resistant microbiota was analyzed by 16S rRNA gene amplification sequencing. RESULTS: The small intestine was the main site for the location of ARG donor bacteria and ARGs. The intestinal microbiota richness of the small intestine (duodenum and jejunum) and the large intestine (cecum, colon, and rectum) increased, and the ileum microbiota richness decreased under the action of donor bacteria. The differences in the number of bacteria in the small intestine and the large intestine, as well as the relative richness of Firmicutes from the small intestine to the large intestine, decreased. By contrast, the relative abundance of Proteobacteria increased. The intake of resistant plasmids alleviated the impact of antibiotics on intestinal microbiota, particularly increasing the proportion of Proteobacteria and Bacteroides, which were presumed to be susceptible to ARGs. DISCUSSION: The acquisition of ARGs by intestinal microbes is an important reason why infectious diseases are difficult to cure, which brings risks to human health and intestinal microecology.202439764443
739810.9999Spread of chloramphenicol and tetracycline resistance genes by plasmid mobilization in agricultural soil. Spread of antibiotic resistance genes (ARGs) poses a worldwide threat to public health and food safety. However, ARG spread by plasmid mobilization, a broad host range transfer system, in agricultural soil has received little attention. Here, we investigated the spread of chloramphenicol resistance gene (CRG) and tetracycline resistance gene (TRG) in agricultural soil by mobilization of pSUP106 under different conditions, including different concentrations of nutrients, temperatures, soil depths, rhizosphere soils, and soil types. The number of resistant bacteria isolated in non-sterilized soil from the experiments was approximately 10(4) to 10(7) per gram of soil, belonging to 5-10 species from four genera, including nonpathogen, opportunistic pathogen, pathogen bacteria, and gram-positive and gram-negative bacteria, depending on the experiment conditions. In sterilized soil, higher levels of nutrients and higher temperatures promoted plasmid mobilization and ARG expression. Topsoil and deep soil might not support the spread of antibiotic resistance, while ARG dissemination by plasmid mobilization was better supported by maize rhizosphere and loam soils. All these factors might change bacterial growth and the activity of bacteria and lead to the above influence. Introduction of only the donor and helper, or the donor alone also resulted in the transfer of ARGs and large numbers of antibiotic resistant bacteria (ARB), indicating that some indigenous bacteria contain the elements necessary for plasmid mobilization. Our results showed that plasmid mobilization facilitated dissemination of ARGs and ARB in soil, which led to the disturbance of indigenous bacterial communities. It is important to clear ARG dissemination routes and inhibit the spread of ARGs.202031991360
739920.9999Aquatic animals promote antibiotic resistance gene dissemination in water via conjugation: Role of different regions within the zebra fish intestinal tract, and impact on fish intestinal microbiota. The aqueous environment is one of many reservoirs of antibiotic resistance genes (ARGs). Fish, as important aquatic animals which possess ideal intestinal niches for bacteria to grow and multiply, may ingest antibiotic resistance bacteria from aqueous environment. The fish gut would be a suitable environment for conjugal gene transfer including those encoding antibiotic resistance. However, little is known in relation to the impact of ingested ARGs or antibiotic resistance bacteria (ARB) on gut microbiota. Here, we applied the cultivation method, qPCR, nuclear molecular genetic marker and 16S rDNA amplicon sequencing technologies to develop a plasmid-mediated ARG transfer model of zebrafish. Furthermore, we aimed to investigate the dissemination of ARGs in microbial communities of zebrafish guts after donors carrying self-transferring plasmids that encode ARGs were introduced in aquaria. On average, 15% of faecal bacteria obtained ARGs through RP4-mediated conjugal transfer. The hindgut was the most important intestinal region supporting ARG dissemination, with concentrations of donor and transconjugant cells almost 25 times higher than those of other intestinal segments. Furthermore, in the hindgut where conjugal transfer occurred most actively, there was remarkable upregulation of the mRNA expression of the RP4 plasmid regulatory genes, trbBp and trfAp. Exogenous bacteria seem to alter bacterial communities by increasing Escherichia and Bacteroides species, while decreasing Aeromonas compared with control groups. We identified the composition of transconjugants and abundance of both cultivable and uncultivable bacteria (the latter accounted for 90.4%-97.2% of total transconjugants). Our study suggests that aquatic animal guts contribute to the spread of ARGs in water environments.201728742284
385630.9998Food-borne microbes influence conjugative transfer of antimicrobial resistance plasmids in pre-disturbed gut microbiome. Ingestion of antibiotic-resistant bacteria following antibiotic treatments may lead to the transfer of antimicrobial resistance genes (ARGs) within a disturbed gut microbiota. However, it remains unclear whether and how microbes present in food matrices influence ARG transfer. Thus, a previously established mouse model, which demonstrated the conjugative transfer of a multi-drug resistance plasmid (pIncA/C) from Salmonella Heidelberg (donor) to Salmonella Typhimurium (recipient), was used to assess the effects of food-borne microbes derived from fresh carrots on pIncA/C transfer. Mice were pre-treated with ampicillin, streptomycin, sulfamethazine, or left untreated as a control to facilitate bacterial colonization. Contrary to previous findings where high-density colonization of the donor and recipient bacteria occurred in the absence of food-borne microbes, the presence of these microbes resulted in a low abundance of S. Typhimurium and no detection of S. Typhimurium transconjugants in the fecal samples from any of the mice. However, in mice pre-treated with streptomycin, a significant reduction in microbial species richness allowed for the significant enrichment of Enterobacteriaceae and pIncA/C transfer to bacteria from the genera Escherichia, Enterobacter, Citrobacter, and Proteus. These findings suggest that food-borne microbes may enhance ARG dissemination by influencing the population dynamics of bacterial hosts within a pre-disturbed gut microbiome.202540315481
738340.9998Spread of plasmids carrying antibiotic resistance genes in soil-lettuce-snail food chain. Fertilization can change the composition of antibiotic resistance genes(ARGs) and their host bacteria in agricultural fields, while complex microbial activities help ARGs into crops and transmit them to humans through agricultural products.Therefore, this study constructed a farmland food chain with soil-lettuce-snail as a typical structure, added genetically engineered Pseudomonas fluorescens containing multidrug-resistant plasmid RP4 to track its spread in the farmland food chain, and used different fertilization methods to explore its influence on the spread and diffusion of ARGs and intl1 in the farmland food chain. It was found that exogenous Pseudomonas can enter plants from soil and pass into snails' intestines, and there is horizontal gene transfer phenomenon of RP4 plasmid in bacteria. At different interfaces of the constructed food chain, the addition of exogenous drug-resistant bacteria had different effects on the total abundance of ARGs and intl1. Fertilization, especially manure, not only promoted the spread of Pseudomonas aeruginosa and the transfer of RP4 plasmid levels, but also significantly increased the total abundance of ARGs and intl1 at all interfaces of the constructed food chain. The main ARGs host bacteria in the constructed food chain include Proteobacteria, Bacteroides, and Firmicutes, while Flavobacterium of Bacteroides is the unique potential host bacteria of RP4 plasmid. In conclusion, this study provides a reference for the risk assessment of ARGs transmitted to the human body through the food chain, and has important practical significance to reduce the antibiotic resistance contamination of agricultural products and ensure the safety of vegetable basket.202438700770
325750.9998The effect of antibiotics on the gut microbiome: a metagenomics analysis of microbial shift and gut antibiotic resistance in antibiotic treated mice. BACKGROUND: Emergence of antibiotic resistance is a global public health concern. The relationships between antibiotic use, the gut community composition, normal physiology and metabolism, and individual and public health are still being defined. Shifts in composition of bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) after antibiotic treatment are not well-understood. METHODS: This project used next-generation sequencing, custom-built metagenomics pipeline and differential abundance analysis to study the effect of antibiotic monotherapy on resistome and taxonomic composition in the gut of Balb/c mice infected with E. coli via transurethral catheterization to investigate the evolution and emergence of antibiotic resistance. RESULTS: There is a longitudinal decrease of gut microbiota diversity after antibiotic treatment. Various ARGs are enriched within the gut microbiota despite an overall reduction of the diversity and total amount of bacteria after antibiotic treatment. Sometimes treatment with a specific class of antibiotics selected for ARGs that resist antibiotics of a completely different class (e.g. treatment of ciprofloxacin or fosfomycin selected for cepA that resists ampicillin). Relative abundance of some MGEs increased substantially after antibiotic treatment (e.g. transposases in the ciprofloxacin group). CONCLUSIONS: Antibiotic treatment caused a remarkable reduction in diversity of gut bacterial microbiota but enrichment of certain types of ARGs and MGEs. These results demonstrate an emergence of cross-resistance as well as a profound change in the gut resistome following oral treatment of antibiotics.202032228448
738660.9998Regulation of Antibiotic Resistance Genes on Agricultural Land Is Dependent on Both Choice of Organic Amendment and Prevalence of Predatory Bacteria. Antibiotic resistance genes (ARGs) are widespread in the environment, and soils, specifically, are hotspots for microorganisms with inherent antibiotic resistance. Manure and sludge used as fertilizers in agricultural production have been shown to contain vast amounts of ARGs, and due to continued applications, ARGs accumulate in agricultural soils. Some soils, however, harbor a resilience capacity that could depend on specific soil properties, as well as the presence of predatory bacteria that are able to hydrolyse living bacteria, including bacteria of clinical importance. The objectives of this study were to (i) investigate if the antibiotic resistance profile of the soil microbiota could be differently affected by the addition of cow manure, chicken manure, and sludge, and (ii) investigate if the amendments had an effect on the presence of predatory bacteria. The three organic amendments were mixed separately with a field soil, divided into pots, and incubated in a greenhouse for 28 days. Droplet digital PCR (ddPCR) was used to quantify three ARGs, two predatory bacteria, and total number of bacteria. In this study, we demonstrated that the choice of organic amendment significantly affected the antibiotic resistance profile of soil, and promoted the growth of predatory bacteria, while the total number of bacteria was unaffected.202439200050
740970.9998Longitudinal screening of antibiotic residues, antibiotic resistance genes and zoonotic bacteria in soils fertilized with pig manure. Fertilization with animal manure is one of the main routes responsible for the introduction of antibiotic residues, antibiotic resistance genes, and zoonotic bacteria into the environment. The aim of this study was to assess the effect of the use of pig (swine) manure as a fertilizer on the presence and fate of six antibiotic residues, nine antibiotic resistance genes, and bacteria (zoonotic bacteria Salmonella spp. and Campylobacter spp. and E. coli as indicator for Gram-negative bacterial species of the microbiota of livestock) on five fields. To the best of our knowledge, the present study is the first to assess a multitude of antibiotic residues and resistance to several classes of antibiotics in pig manure and in fertilized soil over time in a region with an intensive pig industry (Flanders, Belgium). The fields were sampled at five consecutive time points, starting before fertilization up to harvest. Low concentrations of antibiotic residues could be observed in the soils until harvest. The antibiotic resistance genes studied were already present at background levels in the soil environment prior to fertilization, but after fertilization with pig manure, an increase in relative abundance was observed for most of them, followed by a decline back to background levels by harvest-time on all of the fields studied. No apparent differences regarding the presence of antibiotic resistance genes in soils were observed between those fertilized with manure that either contained antibiotic residues or not. With regard to dissemination of resistance, the results presented in this study confirm that fertilization with animal manure directly adds resistance genes to the soil. In addition, it shows that this direct mechanism may be more important than possible selective pressure in soil-dwelling bacteria exerted by antibiotic residues present in the manure. These results also indicate that zoonotic bacteria detected in the manure could be detected in the soil environment directly after fertilization, but not after 1 month. In conclusion, although some antibiotic residues may be present in both manure and soil at concentrations to exert selective pressure, it seems that antibiotic resistance is mostly introduced directly to soil through fertilization with animal manure.202032410188
740280.9998Variability of the Ability of Complex Microbial Communities to Exclude Microbes Carrying Antibiotic Resistance Genes in Rabbits. Reducing antibiotic use is a necessary step toward less antibiotic resistance in livestock, but many antibiotic resistance genes can persist for years, even in an antibiotic-free environment. In this study, we investigated the potential of three fecal complex microbial communities from antibiotic-naive does to drive the microbiota of kits from antibiotic-exposed dams and outcompete bacteria-carrying antibiotic-resistant genes. The fecal complex microbial communities were either orally delivered or simply added as fresh fecal pellets in four to five nests that were kept clean from maternal feces. Additionally, four nests were cleaned for the maternal feces and five nests were handled according to the common farm practice (i.e., cleaning once a week) as controls. At weaning, we measured the relative abundance of 26 antibiotic resistance genes, the proportion of Enterobacteriaceae resistant to tetracycline and sulfonamide antibiotics, and the taxonomic composition of the microbiota by sequencing the 16S rRNA genes of one kit per nest. Changing the surrounding microbes of the kits can hinder the transmission of antibiotic resistance genes from one generation to the next, but the three communities widely differed in their ability to orient gut microbes and in their impact on antibiotic resistance genes. The most efficient delivery of the microbial community reduced the proportion of resistant Enterobacteria from 93 to 9%, decreased the relative abundance of eight antibiotic resistance genes, and changed the gut microbes of the kits at weaning. The least efficient did not reduce any ARG or modify the bacterial community. In addition, adding fecal pellets was more efficient than the oral inoculation of the anaerobic suspension derived from these fecal pellets. However, we were unable to predict the outcome of the exclusion from the data of the donor does (species composition and abundance of antibiotic resistance genes). In conclusion, we revealed major differences between microbial communities regarding their ability to exclude antibiotic resistance genes, but more work is needed to understand the components leading to the successful exclusion of antibiotic resistance genes from the gut. As a consequence, studies about the impact of competitive exclusion should use several microbial communities in order to draw general conclusions.201931333614
740090.9998Investigating the effects of municipal and hospital wastewaters on horizontal gene transfer. Horizontal gene transfer (HGT) plays an important role in the dissemination of antibiotic resistance genes. In sewer systems, human-associated and environmental bacteria are mixed together and exposed to many substances known to increase HGT, including various antibacterial compounds. In wastewaters, those substances are most often detected below concentrations known to induce HGT individually. Still, it is possible that such wastewaters induce HGT, for example via mixture effects. Here, a panel of antibiotics, biocides and other pharmaceuticals was measured in filter-sterilized municipal and hospital wastewater samples from Gothenburg, Sweden. The effects on HGT of the chemical mixtures in these samples were investigated by exposing a complex bacterial donor community together with a GFP-tagged E. coli recipient strain. Recipients that captured sulfonamide resistance-conferring mobile genetic elements (MGEs) from the bacterial community were enumerated and characterized by replicon typing, antibiotic susceptibility testing and long read sequencing. While exposure to municipal wastewater did not result in any detectable change in HGT rates, exposure to hospital wastewater was associated with an increase in the proportion of recipients that acquired sulfonamide resistance but also a drastic decrease in the total number of recipients. Although, concentrations were generally higher in hospital than municipal wastewater, none of the measured substances could individually explain the observed effects of hospital wastewater. The great majority of the MGEs captured were IncN plasmids, and resistance to several antibiotics was co-transferred in most cases. Taken together, the data show no evidence that chemicals present in the studied municipal wastewater induce HGT. Still, the increased relative abundance of transconjugants after exposure to hospital wastewater could have implications for the risks of both emergence and transmission of resistant bacteria.202133631686
7388100.9998Poultry manure-derived microorganisms as a reservoir and source of antibiotic resistance genes transferred to soil autochthonous microorganisms. Animal husbandry is increasing yearly due to the growing demand for meat and livestock products, among other reasons. To meet these demands, prophylactic antibiotics are used in the livestock industry (i.e., poultry farming) to promote health and stimulate animal growth. However, antibiotics are not fully metabolized by animals, and they are evacuated to the environment with excreta. Animal manure is used as fertilizer to reduce the volume of waste generated in the livestock sector. However, manure often contains microorganisms harboring antibiotic resistance genes (ARGs). Then, the microbiome of manure applicate to the soil may contribute to the spread of antibiotic resistance in the environment, including autochthonous soil-dwelling microorganisms. The present study was conducted during the crops growing season in Poland (May to September 2019) to determine the influence of poultry manure as well as poultry manure supplemented with selected antibiotics on the diversity of the soil microbiome in treatments that had not been previously fertilized with manure and the ability of antibiotic-resistant bacteria to transfer ARGs to other soil bacteria. Antibiotic concentrations were elevated at the beginning of the study and decreased over time. Poultry manure induced significant changes in the structure of microbial communities in soil; the diversity of the soil microbiome decreased, and the abundance of bacterial genera Bradyrhizobium, Streptomyces, and Pseudomonas, which are characteristic of the analyzed manure, increased. Over time, soil microbial diversity was restored to the state observed before the application of manure. Genes conferring resistance to multiple drugs as well as genes encoding resistance to bacitracin and aminoglycosides were the most frequently identified ARGs in the analyzed bacteria, including on mobile genetic elements. Multidrug resistance was observed in 17 bacterial taxa, whereas ARGs were identified in 32 bacterial taxa identified in the soil microbiome. The results of the study conclude that the application of poultry manure supplemented with antibiotics initially affects soil microbiome and resistome diversity but finally, the soil shows resilience and returns to its original state after time, with most antibiotic resistance genes disappearing. This phenomenon is of great importance in sustainable soil health after manure application.202337832303
3339110.9998Examining the taxonomic distribution of tetracycline resistance in a wastewater plant. Microbial communities serve as reservoirs of antibiotic resistance genes (ARGs) and facilitate the dissemination of these genes to bacteria that infect humans. Relatively little is known about the taxonomic distribution of bacteria harboring ARGs in these reservoirs and the avenues of transmission due to the technical hurdles associated with characterizing the contents of complex microbial populations and the assignment of genes to particular genomes. Focusing on the array of tetracycline resistance (Tc(r)) genes in the primary and secondary phases of wastewater treatment, 17 of the 22 assayed Tc(r) genes were detected in at least one sample. We then applied emulsion, paired isolation, and concatenation PCR (epicPCR) to link tetracycline resistance genes to specific bacterial hosts. Whereas Tc(r) genes tend to vary in their distributions among bacterial taxa according to their modes of action, there were numerous instances in which a particular Tc(r) gene was associated with a host that was distantly related to all other bacteria bearing the same gene, including several hosts not previously identified. Tc(r) genes are far less host-restricted than previously assumed, indicating that complex microbial communities serve as settings where ARGs are spread among divergent bacterial phyla.202438317688
7384120.9998Uncovering antimicrobial resistance in three agricultural biogas plants using plant-based substrates. Antimicrobial resistance (AMR) is becoming an increasing global concern and the anaerobic digestion (AD) process represents a potential transmission route when digestates are used as fertilizing agents. AMR contaminants, e.g. antibiotic-resistant bacteria (ARB) and plasmid-mediated antibiotic resistance genes (ARGs) have been found in different substrates and AD systems, but not yet been investigated in plant-based substrates. AMR transfer from soils to vegetable microbiomes has been observed, and thus crop material potentially represents a so far neglected AMR load in agricultural AD processes, contributing to AMR spread. In order to test this hypothesis, this study examined the AMR situation throughout the process of three biogas plants using plant-based substrates only, or a mixture of plant-based and manure substrates. The evaluation included a combination of culture-independent and -dependent methods, i.e., identification of ARGs, plasmids, and pathogenic bacteria by DNA arrays, and phylogenetic classification of bacterial isolates and their phenotypic resistance pattern. To our knowledge, this is the first study on AMR in plant-based substrates and the corresponding biogas plant. The results showed that the bacterial community isolated from the investigated substrates and the AD processing facilities were mainly Gram-positive Bacillus spp. Apart from Pantoea agglomerans, no other Gram-negative species were found, either by bacteria culturing or by DNA typing array. In contrast, the presence of ARGs and plasmids clearly indicated the existence of Gram-negative pathogenic bacteria, in both substrate and AD process. Compared with substrates, digestates had lower levels of ARGs, plasmids, and culturable ARB. Thus, digestate could pose a lower risk of spreading AMR than substrates per se. In conclusion, plant-based substrates are associated with AMR, including culturable Gram-positive ARB and Gram-negative pathogenic bacteria-associated ARGs and plasmids. Thus, the AMR load from plant-based substrates should be taken into consideration in agricultural biogas processing.202235306061
3715130.9998Deposition of resistant bacteria and resistome through FMT in germ-free piglets. Faecal microbiota transplantation (FMT) has received considerable attention in recent years due to its remarkable efficacy in restoring a normal gut microbiome. Here, we established the groups of post-FMT recipient piglets using germ-free piglets during early life to characterize the colonization of gut microbiota composition and the enrichment of resistance gene acquisition. By metagenomic analysis, we identified 115 bacterial phyla and 2111 bacterial genera that were acquired by the FMT recipients. We found that early-life microbial colonization and the spread of resistomes in recipient piglets were age dependent. A total of 425, 425 and 358 AR genes primarily belonging to 114, 114 and 102 different types were detected in the donors, post-FMT recipients in the FMT-3D group and post-FMT recipients in the FMT-15D group respectively. Genes that encoded tetracycline, macrolide and chloramphenicol resistance proteins were the most dominant AR genes, and the results corresponded with the exposure of antibiotic consumption at farm. Bacteroides, Escherichia, Clostridium, Parabacteroides, Treponema, Lactobacillus and Enterococcus were significantly correlated with the distribution of AR genes. More importantly, the relative abundance of AR genes was positively correlated with the levels of mobile genetic elements. Our results indicate that early-life microbial colonization can persistently shape the gut microbiota and antibiotic resistome.202133894059
7403140.9998Effect of Enrofloxacin on the Microbiome, Metabolome, and Abundance of Antibiotic Resistance Genes in the Chicken Cecum. Enrofloxacin is an important antibiotic for the treatment of Salmonella infections in livestock and poultry. However, the effects of different concentrations of enrofloxacin on the bacterial and metabolite compositions of the chicken gut and changes in the abundance of resistance genes in cecum contents remain unclear. To investigate the effects of enrofloxacin on chickens, we orally administered different concentrations of enrofloxacin to 1-day-old chickens and performed 16S rRNA gene sequencing to assess changes in the gut microbiomes of chickens after treatment. The abundance of fluoroquinolone (FQ) resistance genes was measured using quantitative PCR. Metabolomics techniques were used to examine the cecal metabolite composition. We found that different concentrations of enrofloxacin had different effects on cecum microorganisms, with the greatest effect on cecum microbial diversity in the low-concentration enrofloxacin group at day 7. Enrofloxacin use reduced the abundance of beneficial bacteria such as Lactobacillaceae and Oscillospira. Furthermore, cecum microbial diversity was gradually restored as the chickens grew. In addition, enrofloxacin increased the abundance of resistance genes, and there were differences in the changes in abundance among different antibiotic resistance genes. Moreover, enrofloxacin significantly affected linoleic acid metabolism, amino acid metabolism, and signaling pathways. This study helps improve our understanding of how antibiotics affect host physiological activities and provides new insights into the rational use of drugs in poultry farming. The probiotics and metabolites that we identified could be used to modulate the negative effects of antibiotics on the host, which requires further study. IMPORTANCE In this study, we investigated changes in the cecum flora, metabolites, and abundances of fluoroquinolone antibiotic resistance genes in chickens following the use of different concentrations of enrofloxacin. These results were used to determine the effects of enrofloxacin on chick physiology and the important flora and metabolites that might contribute to these effects. In addition, these results could help in assessing the effect of enrofloxacin concentrations on host metabolism. Our findings could help guide the rational use of antibiotics and mitigate the negative effects of antibiotics on the host.202336840593
3859150.9998Co-selection of antibiotic resistance via copper shock loading on bacteria from a drinking water bio-filter. Heavy metal contamination of source water frequently occurred in developing countries as a result of accidents. To address the problems, most of the previous studies have focused on engineering countermeasures. In this study, we investigated the effects of heavy metals, particularly copper, on the development of antibiotic resistance by establishing a copper shock loading test. Results revealed that co-selection occurred rapidly within 6 h. Copper, at the levels of 10 and 100 mg/L, significantly increased bacterial resistance to the antibiotics tested, including rifampin, erythromycin, kanamycin, and a few others. A total of 117 antimicrobial-resistance genes were detected from 12 types of genes, and the relative abundance of most genes (particularly mobile genetic elements intⅠand transposons) was markedly enriched by at least one fold. Furthermore, the copper shock loading altered the bacterial community. Numerous heavy metal and antibiotic resistant strains were screened out and enriched. These strains are expected to enhance the overall level of resistance. More noticeably, the majority of the co-selected antibiotic resistance could sustain for at least 20 h in the absence of copper and antimicrobial drugs. Resistance to vancomycin, erythromycin and lincomycin even could remain for 7 days. The prominent selection pressure by the copper shock loading implies that a real accident most likely poses similar impacts on the water environment. An accidental release of heavy metals would not only cause harm to the ecological environment, but also contribute to the development of bacterial antibiotic resistance. Broader concerns should be raised about the biological risks caused by sudden releases of pollutants by accidents.201829059628
3862160.9998Interaction of tetracycline and copper co-intake in inducing antibiotic resistance genes and potential pathogens in mouse gut. The widespread use of copper and tetracycline as growth promoters in the breeding industry poses a potential threat to environmental health. Nevertheless, to the best of our knowledge, the potential adverse effects of copper and tetracycline on the gut microbiota remain unknown. Herein, mice were fed different concentrations of copper and/or tetracycline for 6 weeks to simulate real life-like exposure in the breeding industry. Following the exposure, antibiotic resistance genes (ARGs), potential pathogens, and other pathogenic factors were analyzed in mouse feces. The co-exposure of copper with tetracycline significantly increased the abundance of ARGs and enriched more potential pathogens in the gut of the co-treated mice. Copper and/or tetracycline exposure increased the abundance of bacteria carrying either ARGs, metal resistance genes, or virulence factors, contributing to the widespread dissemination of potentially harmful genes posing a severe risk to public health. Our study provides insights into the effects of copper and tetracycline exposure on the gut resistome and potential pathogens, and our findings can help reduce the risks associated with antibiotic resistance under the One Health framework.202438527398
3861170.9998Dietary intake of enrofloxacin promotes the spread of antibiotic resistance from food to simulated human gut. Antibiotic residues are commonly found in food. The effect of dietary exposure to veterinary antibiotics on the transmission of antibiotic resistant bacteria and antibiotic resistance genes from food to humans is unknown. We found that dietary exposure to enrofloxacin reduced microbial diversity, interactions and the immune responses, weakened the colonization resistance of the resident microbiota, and promoted the colonization of exogenous Escherichia coli K-12 MG1655 in the simulated human intestine both in vitro and in vivo experiments in mice. In addition to the growth advantages for potential most likely bacterial hosts of ARGs under enrofloxacin exposure, the dietary exposure to enrofloxacin promoted horizontal transfer of resistance plasmids and altered the simulated human gut antibiotic resistome in a time-dependent manner. Collectively, these findings demonstrated that dietary intake of enrofloxacin promoted the colonization of E. coli K-12 MG1655 in the simulated human intestine and the horizontal transfer of antibiotic resistance genes, highlighting the risk of antibiotic resistance transmission from food to humans mediated by dietary exposure to veterinary antibiotics.202540121546
7702180.9998A metagenomic analysis for combination therapy of multiple classes of antibiotics on the prevention of the spread of antibiotic-resistant genes. Antibiotics used systemically to treat infections may have off-target effects on the gut microbiome, potentially resulting in the emergence of drug-resistant bacteria or selection of pathogenic species. These organisms may present a risk to the host and spread to the environment with a risk of transmission in the community. To investigate the risk of emergent antibiotic resistance in the gut microbiome following systemic treatment with antibiotics, this metagenomic analysis project used next-generation sequencing, a custom-built metagenomics pipeline, and differential abundance analysis to study the effect of antibiotics (ampicillin, ciprofloxacin, and fosfomycin) in monotherapy and different combinations at high and low doses, to determine the effect on resistome and taxonomic composition in the gut of Balb/c mice. The results showed that low-dose monotherapy treatments showed little change in microbiome composition but did show an increase in expression of many antibiotic-resistant genes (ARGs) posttreatment. Dual combination treatments allowed the emergence of some conditionally pathogenic bacteria and some increase in the abundance of ARGs despite a general decrease in microbiota diversity. Triple combination treatment was the most successful in inhibiting emergence of relevant opportunistic pathogens and completely suppressed all ARGs after 72 h of treatment. The relative abundances of mobile genetic elements that can enhance transmission of antibiotic resistance either decreased or remained the same for combination therapy while increasing for low-dose monotherapy. Combination therapy prevented the emergence of ARGs and decreased bacterial diversity, while low-dose monotherapy treatment increased ARGs and did not greatly change bacterial diversity.202337908118
3680190.9998Metagenomic Insights Into the Contribution of Phages to Antibiotic Resistance in Water Samples Related to Swine Feedlot Wastewater Treatment. In this study, we examined the types of antibiotic resistance genes (ARGs) possessed by bacteria and bacteriophages in swine feedlot wastewater before and after treatment using a metagenomics approach. We found that the relative abundance of ARGs in bacterial DNA in all water samples was significantly higher than that in phages DNA (>10.6-fold), and wastewater treatment did not significantly change the relative abundance of bacterial- or phage-associated ARGs. We further detected the distribution and diversity of the different types of ARGs according to the class of antibiotics to which they confer resistance, the tetracycline resistance genes were the most abundant resistance genes and phages were more likely to harbor ATP-binding cassette transporter family and ribosomal protection genes. Moreover, the colistin resistance gene mcr-1 was also detected in the phage population. When assessing the contribution of phages in spreading different groups of ARGs, β-lactamase resistance genes had a relatively high spreading ability even though the abundance was low. These findings possibly indicated that phages not only could serve as important reservoir of ARG but also carry particular ARGs in swine feedlot wastewater, and this phenomenon is independent of the environment.201830459724