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811000.9884Removal 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
745910.9881Field-realistic dose of cefotaxime enhances potential mobility of β-lactam resistance genes in the gut microbiota of zebrafish (Danio rerio). With large amounts of cephalosporin end up in natural ecosystems, water has been acknowledged as the large reservoir of β-lactam resistance over the past decades. However, there is still insufficient knowledge available on the function of the living organisms to the transmission of antibiotic resistance. For this reason, in this study, using adult zebrafish (Danio rerio) as animal model, exposing them to environmentally relevant dose of cefotaxime for 150 days, we asked whether cefotaxime contamination accelerated β-lactam resistance in gut microbiota as well as its potential transmission. Results showed that some of β-lactam resistance genes (βRGs) were intrinsic embedded in intestinal microbiome of zebrafish even without antibiotic stressor. Across cefotaxime treatment, the abundance of most βRGs in fish gut microbiome decreased apparently in the short term firstly, and then increased with the prolonged exposure, forming distinctly divergent βRG profiles with antibiotic-untreated zebrafish. Meanwhile, with the rising concentration of cefotaxime, the range of βRGs' host-taxa expanded and the co-occurrence relationships of mobile genetics elements (MGEs) with βRGs intensified, indicating the enhancement of βRGs' mobility in gut microbiome when the fish suffered from cefotaxime contamination. Furthermore, the path of partial least squares path modeling (PLS-PM) gave an integral assessment on the specific causality of cefotaxime treatment to βRG profiles, showing that cefotaxime-mediated βRGs variation was most ascribed to the alteration of MGEs under cefotaxime stress, followed by bacterial community, functioning both direct influence as βRG-hosts and indirect effects via affecting MGEs. Finally, pathogenic bacteria Aeromonas was identified as the critical host for multiple βRGs in fish guts, and its β-lactam resistance increased over the duration time of cefotaxime exposure, suggesting the potential spreading risks for the antibiotic-resistant pathogens from environmental ecosystems to clinic. Overall, our finding emphasized cefotaxime contamination in aquatic surroundings could enhance the β-lactam resistance and its transmission mobility in fish bodies.202336857871
706120.9879Dissemination of antibiotic resistance genes through soil-plant-earthworm continuum in the food production environment. Treated municipal wastewater (TMW) can provide a reliable source of irrigation water for crops, which is especially important in arid areas where water resources are limited or prone to drought. Nonetheless, TMW may contain residual antibiotics, potentially exposing the crops to these substances. The goal of this study was to investigate the dissemination of antibiotics resistance genes (ARGs) in the soil-plant-earthworm continuum after irrigation of spinach and radish plants with TMW containing trimethoprim, sulfamethoxazole, and sulfapyridine in a greenhouse experiment, followed by feeding of earthworms with harvested plant materials. Our results showed that antibiotic resistance genes (ARGs) were enriched in the soil-plant-earthworm microbiomes irrigated with TMW and TMW spiked with higher concentrations of antibiotics. The number of ARGs and antibiotic-resistant bacteria (ARB) enrichment varied with plant type, with spinach harboring a significantly higher amount of ARGs and ARB compared to radish. Our data showed that bulk and rhizosphere soils of spinach and radish plants irrigated with MilliQ water, TMW, TMW10, or TMW100 had significant differences in bacterial community (p < 0.001), ARG (p < 0.001), and virulence factor gene (VFG) (p < 0.001) diversities. The abundance of ARGs significantly decreased from bulk soil to rhizosphere to phyllosphere and endosphere. Using metagenome assembled genomes (MAGs), we recovered many bacterial MAGs and a near complete genome (>90 %) of bacterial MAG of genus Leclercia adecarboxylata B from the fecal microbiome of earthworm that was fed harvested radish tubers and spinach leaves grown on TMW10 irrigated waters, and this bacterium has been shown to be an emerging pathogen causing infection in immunocompromised patients that may lead to health complications and death. Therefore, crops irrigated with TMW containing residual antibiotics and ARGs may lead to increased incidences of enrichment of ARB in the soil-plant-earthworm continuum.202438101104
774830.9879Bacillus subtilis reduces antibiotic resistance genes of animal sludge in vermicomposting by improving heat stress tolerance of Eisenia foetida and bacterial community adjustment. Antibiotic resistance genes (ARGs) in livestock industry have been recognized as a kind of pollutant. The effect of Bacillus subtilis (B. subtilis) as an additive for the reduction of ARGs in animal sludge from livestock and poultry wastewater treatment plant during vermicomposting was investigated. We also evaluated the oxidative stress level and growth of earthworms, Eisenia foetida, bacterial community succession, and the quality of the end products. Two treatments were conducted using B. subtilis, one at 18 °C and another at 28 °C. Controls were setup without the bacteria. The results showed that inoculation of B. subtilis promoted the degradation of organics at 28 °C and increased the germination index to 236%. The increased activities of the superoxide dismutase (1.69 U/mg pr) and catalase (8.05 U/mg pr) and the decreased activity of malondialdehyde (0.02 nmol/mg pr) by B. subtilis at 28 °C showed that the earthworms were relieved of heat stress. The addition of B. subtilis reduced the abundance of 32 target ARGs, including integron (intI-1), transposase (IS613) and resistant genes, such as sulfonamide (sul2), quinolone (oprJ), macrolide-lincosamide-streptogramin group B (ermF, ermB), tetracycline (tetL-02, tetX), β-lactama (blaOXA10-01) and aminoglycoside [strB, aac(6')-Ib(aka aacA4)-01, aac(6')-Ib(aka aacA4)-02]. Organic matter degrading Membranicola, Paludisphaera, Sphingorhabdus and uncultured bacterium belonging to the order Chitinophagales, nitrifying and nitrogen-fixing Singulisphaera and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, soil remediating Achromobacter, and plant growth promoting Kaistia, Galbibacter and Ilumatobacter were increased significantly (P < 0.05). However, the growth of harmful bacteria such as Burkholderiaceae was inhibited in the vermicompost. In earthworm guts, the probiotic Mesorhizobium was promoted, while the pathogenic uncultured bacterium belonging to the family Enterobacteriaceae was reduced. Besides, B. subtilis enhanced the host relationships between bacteria and ARGs. These findings might be helpful in the removal of ARGs in animal wastes and in understanding the synergy between earthworms and microorganisms.202336529325
806640.9879Inoculation of thermophilic bacteria from giant panda feces into cattle manure reduces gas emissions and decreases resistance gene prevalence in short-term composting. Here, thermophilic bacteria (TB) with cellulose degradation functions were screened from composting panda feces and applied to cattle manure composting. TB (Aeribacillus pallidus G5 and Parageobacillus toebii G12) inoculation led to remarkable improvement of the compost temperature, prolonging of the thermophilic stage and shortening of the composting process, resulting in increased manure harmlessness (GI ≥ 70%), compost humification, and greenhouse gas emission reduction (14.19%-22.57%), compared with the control compost, within 15 days of composting. In particular, G5 inoculation reduced NH(3) emissions by 41.97% relative to control composts over 15 days. G5 was capable of rapidly colonizing in the composts, and its inoculation immediately enriched the genera of Firmicutes, and simultaneously decreased the genera of Proteobacteria, contributing to the elimination of harmful microorganisms. Notably, this strain lacked antibiotic resistance genes, and the absolute abundances of resistance genes and mobile genetic genes (MGEs) decreased the most (by 80.84%). Metagenomic analysis revealed that enzymes capable of producing CO(2), N(2)O, and NH(3) were generally inhibited, while CO(2) fixation and N(2)O and NH(3) reduction enzymes were enriched in the G5 compost, since metagenome-assembled genomes of Proteobacteria harbored more key genes and enzymes in complete pathways for producing N(2)O, NH(3), and CO(2). Moreover, Proteobacteria, such as Pseudomonas and Halopseudomonas, were the main host of resistance genes and MGEs. Overall, the gas emission could be reduced, and more efficient control of resistance genes could be achieved by inhibited the abundance of Proteobacteria during composting. This study provides a safe and effective microbial agent (A. pallidus) for manure treatment.202539642832
694050.9878Higher spreading risk of antibacterial biocide and heavy metal resistance genes than antibiotic resistance genes in aerobic granular sludge. Metagenomic approach was applied to simultaneously reveal the antibiotic resistance genes (ARGs) and antibacterial biocide & metal resistance genes (BMRGs), and the corresponding microbial hosts with high mobility during aerobic granular sludge (AGS) formation process. The results showed that the relative abundance of BMRGs was 88-123 times that of ARGs. AGS process was easier to enrich BMRGs, leading to a greater risk of drug resistance caused by BMRGs than that by ARGs. The enrichments of ARGs and BMRGs in AGS were closely related to several enhanced microbial metabolisms (i.e., cell motility, transposase and ATP-binding cassette transporters) and their corresponding regulatory genes. Several enhanced KEGG Orthologs (KO) functions, such as K01995, K01996, K01997 and K02002, might cause a positive impact on the spread of ARGs and BMRGs, and the main contributors were the largely enriched glycogens accumulating organisms. The first dominant ARGs (adeF) was carried by lots of microbial hosts, which might be enriched and propagated mainly through horizontal gene transfer. Candidatus Competibacter denitrificans simultaneously harbored ARG (cmx) and Cu related RGs (corR). Many enriched bacteria contained simultaneously multiple BMRGs (copR and corR) and mobile genetic elements (integrons and plasmids), granting them high mobility capabilities and contributing to the spread of BMRGs. This study might provide deeper understandings of the proliferation and mobility of ARGs and BMRGs, importantly, highlighted the status of BMRGs, which laid the foundation for the controlling widespread of resistance genes in AGS.202235489476
690460.9877Ionic Liquid Enriches the Antibiotic Resistome, Especially Efflux Pump Genes, Before Significantly Affecting Microbial Community Structure. An expanding list of chemicals may permeabilize bacterial cells and facilitate horizontal gene transfer (HGT), which enhances propagation of antibiotic resistance genes (ARGs) in the environment. Previous studies showed that 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]), an ionic liquid, can facilitate HGT of some ARGs among bacteria. However, the dynamic response of a wider range of ARGs and associated mobile genetic elements (MGEs) in different environments is unknown. Here, we used metagenomic tools to study shifts of the resistome and microbiome in both sediments and freshwater microcosms exposed to [BMIm][PF6]. Exposure for 16 h to 0.1 or 1.0 g/L significantly enriched more than 207 ARG subtypes primarily encoding efflux pumps in freshwater microcosms as well as cultivable antibiotic-resistant bacteria. This resistome enrichment was attributed to HGT facilitated by MGEs (428 plasmids, 61 integron-integrase genes, and 45 gene cassettes were enriched) as well as to HGT-related functional genes. Interestingly, resistome enrichment occurred fast (within 16 h) after [BMIm][PF6] exposure, before any significant changes in bacterial community structure. Similar ARG enrichment occurred in sediment microcosms exposed to [BMIm][PF6] for 28 d, and this longer exposure affected the microbial community structure (e.g., Proteobacteria abundance increased significantly). Overall, this study suggests that [BMIm][PF6] releases could rapidly enrich the antibiotic resistome in receiving environments by increasing HGT and fortuitously selecting for efflux pump genes, thus contributing to ARG propagation.202031944684
697370.9877Carbendazim shapes microbiome and enhances resistome in the earthworm gut. BACKGROUND: It is worrisome that several pollutants can enhance the abundance of antibiotic resistance genes (ARGs) in the environment, including agricultural fungicides. As an important bioindicator for environmental risk assessment, earthworm is still a neglected focus that the effects of the fungicide carbendazim (CBD) residues on the gut microbiome and resistome are largely unknown. In this study, Eisenia fetida was selected to investigate the effects of CBD in the soil-earthworm systems using shotgun metagenomics and qPCR methods. RESULTS: CBD could significantly perturb bacterial community and enrich specific bacteria mainly belonging to the phylum Actinobacteria. More importantly, CBD could serve as a co-selective agent to elevate the abundance and diversity of ARGs, particularly for some specific types (e.g., multidrug, glycopeptide, tetracycline, and rifamycin resistance genes) in the earthworm gut. Additionally, host tracking analysis suggested that ARGs were mainly carried in some genera of the phyla Actinobacteria and Proteobacteria. Meanwhile, the level of ARGs was positively relevant to the abundance of mobile genetic elements (MGEs) and some representative co-occurrence patterns of ARGs and MGEs (e.g., cmx-transposase and sul1-integrase) were further found on the metagenome-assembled contigs in the CBD treatments. CONCLUSIONS: It can be concluded that the enhancement effect of CBD on the resistome in the earthworm gut may be attributed to its stress on the gut microbiome and facilitation on the ARGs dissemination mediated by MGEs, which may provide a novel insight into the neglected ecotoxicological risk of the widely used agrochemicals on the gut resistome of earthworm dwelling in soil. Video abstract.202235436900
724080.9876Effects of industrial effluents containing moderate levels of antibiotic mixtures on the abundance of antibiotic resistance genes and bacterial community composition in exposed creek sediments. Environmental discharges of very high (mg/L) antibiotic levels from pharmaceutical production contributed to the selection, spread and persistence of antibiotic resistance. However, the effects of less antibiotic-polluted effluents (μg/L) from drug-formulation on exposed aquatic microbial communities are still scarce. Here we analyzed formulation effluents and sediments from the receiving creek collected at the discharge site (DW0), upstream (UP) and 3000 m downstream of discharge (DW3000) during winter and summer season. Chemical analyses indicated the largest amounts of trimethoprim (up to 5.08 mg/kg) and azithromycin (up to 0.39 mg/kg) at DW0, but sulfonamides accumulated at DW3000 (total up to 1.17 mg/kg). Quantitative PCR revealed significantly increased relative abundance of various antibiotic resistance genes (ARGs) against β-lactams, macrolides, sulfonamides, trimethoprim and tetracyclines in sediments from DW0, despite relatively high background levels of some ARGs already at UP site. However, only sulfonamide (sul2) and macrolide ARG subtypes (mphG and msrE) were still elevated at DW3000 compared to UP. Sequencing of 16S rRNA genes revealed pronounced changes in the sediment bacterial community composition from both DW sites compared to UP site, regardless of the season. Numerous taxa with increased relative abundance at DW0 decreased to background levels at DW3000, suggesting die-off or lack of transport of effluent-originating bacteria. In contrast, various taxa that were more abundant in sediments than in effluents increased in relative abundance at DW3000 but not at DW0, possibly due to selection imposed by high sulfonamide levels. Network analysis revealed strong correlation between some clinically relevant ARGs (e.g. bla(GES), bla(OXA), ermB, tet39, sul2) and taxa with elevated abundance at DW sites, and known to harbour opportunistic pathogens, such as Acinetobacter, Arcobacter, Aeromonas and Shewanella. Our results demonstrate the necessity for improved management of pharmaceutical and rural waste disposal for mitigating the increasing problems with antibiotic resistance.202031855637
696490.9875Metagenomic approach reveals the role of bioagents in the environmental dissemination risk of rhizosphere soil antibiotic resistance genes pollution. Antibiotic resistance genes (ARGs) have been identified as emerging contaminants, raising concerns around the world. As environmentally friendly bioagents (BA), plant growth-promoting rhizobacteria (PGPR) have been used in agricultural systems. The introduction of BA will lead to the turnover of the microbial communities structure. Nevertheless, it is still unclear how the colonization of the invaded microorganisms could affects the rhizosphere resistome. Consequently, 190 ARGs and 25 integrative and conjugative elements (ICEs) were annotated using the metagenomic approach in 18 samples from the Solanaceae crop rhizosphere soil under BA and conventional treatment (CK) groups. Our study found that, after 90 days of treatment, ARG abundance was lower in the CK group than in the BA group. The results showed that aminoglycoside antibiotic resistance (OprZ), phenicol antibiotic resistance (OprN), aminoglycoside antibiotic resistance (ceoA/B), aminocoumarin antibiotic resistance (mdtB) and phenicol antibiotic resistance (MexW) syntenic with ICEs. Moreover, in 11 sequences, OprN (phenicol antibiotic resistance) was observed to have synteny with ICEPaeLESB58-1, indicating that the ICEs could contribute to the spread of ARGs. Additionally, the binning result showed that the potential bacterial hosts of the ARGs were beneficial bacteria which could promote the nutrition cycle, such as Haliangium, Nitrospira, Sideroxydans, Burkholderia, etc, suggesting that bacterial hosts have a great influence on ARG profiles. According to the findings, considering the dissemination of ARGs, BA should be applied with caution, especially the use of beneficial bacteria in BA. In a nutshell, this study offers valuable insights into ARGs pollution control from the perspective of the development and application of BA, to make effective strategies for blocking pollution risk migration in the ecological environment.202439374754
7219100.9875Occurrence and human exposure risk of antibiotic resistance genes in tillage soils of dryland regions: A case study of northern Ningxia Plain, China. Agricultural soils are important source and sink of antibiotic resistance genes (ARGs). However, little is known about the fate of ARGs in dryland soils, while its human exposure risks were seriously overlooked. Taking the northern Ningxia Plain as a case, this study explored the occurrence of ARGs and its relationship with mobile genetic elements (MGEs), pathogens, and environmental factors. Furthermore, the concentrations of airborne ARGs by soil wind erosion and the human exposure doses of soil ARGs were evaluated. The results showed the abundances of different regions ranged from 4.0 × 10(5) to 1.6 × 10(6) copies/g. Soil ARGs are driven by MGEs, but multiply impacted by soil properties, nutrition, and bacterial community. Vibrio metschnikovii, Acinetobacter schindleri, and Serratia marcescens are potential pathogenic hosts for ARGs. Further exploration revealed the concentration of ARGs loaded in dust by soil wind erosion reached more than 10(5) copies/m(3), which were even higher than those found in sewage treatment plants and hospitals. Skin contact is the primary route of ARGs exposure, with a maximum dose of 24071.33 copies/kg/d, which is largely attributed to ARGs loaded in dust. This study bridged the gap on ARGs in dryland soils, and provided reference for human exposure risk assessment of soil ARGs.202439276744
5169110.9875Genetic Adaptation and Acquisition of Macrolide Resistance in Haemophilus spp. during Persistent Respiratory Tract Colonization in Chronic Obstructive Pulmonary Disease (COPD) Patients Receiving Long-Term Azithromycin Treatment. Patients with chronic obstructive pulmonary disease (COPD) benefit from the immunomodulatory effect of azithromycin, but long-term administration may alter colonizing bacteria. Our goal was to identify changes in Haemophilus influenzae and Haemophilus parainfluenzae during azithromycin treatment. Fifteen patients were followed while receiving prolonged azithromycin treatment (Hospital Universitari de Bellvitge, Spain). Four patients (P02, P08, P11, and P13) were persistently colonized by H. influenzae for at least 3 months and two (P04 and P11) by H. parainfluenzae. Isolates from these patients (53 H. influenzae and 18 H. parainfluenzae) were included to identify, by whole-genome sequencing, antimicrobial resistance changes and genetic variation accumulated during persistent colonization. All persistent lineages isolated before treatment were azithromycin-susceptible but developed resistance within the first months, apart from those belonging to P02, who discontinued the treatment. H. influenzae isolates from P08-ST107 acquired mutations in 23S rRNA, and those from P11-ST2480 and P13-ST165 had changes in L4 and L22. In H. parainfluenzae, P04 persistent isolates acquired changes in rlmC, and P11 carried genes encoding MefE/MsrD efflux pumps in an integrative conjugative element, which was also identified in H. influenzae P11-ST147. Other genetic variation occurred in genes associated with cell wall and inorganic ion metabolism. Persistent H. influenzae strains all showed changes in licA and hgpB genes. Other genes (lex1, lic3A, hgpC, and fadL) had variation in multiple lineages. Furthermore, persistent strains showed loss, acquisition, or genetic changes in prophage-associated regions. Long-term azithromycin therapy results in macrolide resistance, as well as genetic changes that likely favor bacterial adaptation during persistent respiratory colonization. IMPORTANCE The immunomodulatory properties of azithromycin reduce the frequency of exacerbations and improve the quality of life of COPD patients. However, long-term administration may alter the respiratory microbiota, such as Haemophilus influenzae, an opportunistic respiratory colonizing bacteria that play an important role in exacerbations. This study contributes to a better understanding of COPD progression by characterizing the clinical evolution of H. influenzae in a cohort of patients with prolonged azithromycin treatment. The emergence of macrolide resistance during the first months, combined with the role of Haemophilus parainfluenzae as a reservoir and source of resistance dissemination, is a cause for concern that may lead to therapeutic failure. Furthermore, genetic variations in cell wall and inorganic ion metabolism coding genes likely favor bacterial adaptation to host selective pressures. Therefore, the bacterial pathoadaptive evolution in these severe COPD patients raise our awareness of the possible spread of macrolide resistance and selection of host-adapted clones.202336475849
8024120.9874High Concentrations of Tilmicosin Promote the Spread of Multidrug Resistance Gene tolC in the Pig Gut Microbiome Through Mobile Genetic Elements. The impact of antibiotic therapy on the spread of antibiotic resistance genes (ARGs) and its relationship to gut microbiota remains unclear. This study investigated changes in ARGs, mobile genetic elements (MGEs), and gut microbial composition following tilmicosin administration in pigs. Thirty pigs were randomly divided into control (CK), low-concentration (0.2 g/kg; L), and high-concentration (0.4 g/kg; H) groups. Tilmicosin concentration in manure peaked on day 16 of dosing and dropped below detectable levels by day 13 of the withdrawal period. While tilmicosin did not significantly affect the total abundance of macrolide resistance genes (MRGs) (p > 0.05), it significantly increased the abundance of the multidrug resistance gene tolC in the H group compared with the L and CK groups during the withdrawal period (p < 0.05). This increase was associated with a coincidental rise in the abundance of MGEs (e.g., int1 and int2) and the growth of potential tolC-hosting bacteria such as Paenalcaligenes and Proteiniclasticum. Redundancy analysis showed gut microbial composition as the primary driver of MRG abundance, with MGEs, tilmicosin concentration, and manure physicochemical properties playing secondary roles. These findings suggest that high-dose tilmicosin may alter the gut microbiota and promote ARG spread via MGE-mediated transfer.202439795013
6945130.9874Mitigation of antibiotic resistome in swine manure by black soldier fly larval conversion combined with composting. The increasing prevalence of antibiotic resistance genes (ARGs) in animal manure has attracted considerable attention because of their potential contribution to the development of multidrug resistance worldwide. Insect technology may be a promising alternative for the rapid attenuation of ARGs in manure; however, the underlying mechanism remains unclear. This study aimed to evaluate the effects of black soldier fly (BSF, Hermetia illucens [L.]) larvae conversion combined with composting on ARGs dynamics in swine manure and to uncover the mechanisms through metagenomic analysis. Compared to natural composting (i.e. without BSF), BSFL conversion combined with composting reduced the absolute abundance of ARGs by 93.2 % within 28 days. The rapid degradation of antibiotics and nutrient reformulation during BSFL conversion combined with composting indirectly altered manure bacterial communities, resulting in a lower abundance and richness of ARGs. The number of main antibiotic-resistant bacteria (e.g., Prevotella, Ruminococcus) decreased by 74.9 %, while their potential antagonistic bacteria (e.g., Bacillus, Pseudomonas) increased by 128.7 %. The number of antibiotic-resistant pathogenic bacteria (e.g., Selenomonas, Paenalcaligenes) decreased by 88.3 %, and the average number of ARGs carried by each human pathogenic bacterial genus declined by 55.8 %. BSF larvae gut microbiota (e.g., Clostridium butyricum, C. bornimense) could help reduce the risk of multidrug-resistant pathogens. These results provide insight into a novel approach to mitigate multidrug resistance from the animal industry in the environment by using insect technology combined with composting, in particular in light of the global "One Health" requirements.202336966826
7131140.9873Longitudinal study of the short- and long-term effects of hospitalisation and oral trimethoprim-sulfadiazine administration on the equine faecal microbiome and resistome. BACKGROUND: Hospitalisation and antimicrobial treatment are common in horses and significantly impact the intestinal microbiota. Antimicrobial treatment might also increase levels of resistant bacteria in faeces, which could spread to other ecological compartments, such as the environment, other animals and humans. In this study, we aimed to characterise the short- and long-term effects of transportation, hospitalisation and trimethoprim-sulfadiazine (TMS) administration on the faecal microbiota and resistome of healthy equids. METHODS: In a longitudinal experimental study design, in which the ponies served as their own control, faecal samples were collected from six healthy Welsh ponies at the farm (D0-D13-1), immediately following transportation to the hospital (D13-2), during 7 days of hospitalisation without treatment (D14-D21), during 5 days of oral TMS treatment (D22-D26) and after discharge from the hospital up to 6 months later (D27-D211). After DNA extraction, 16S rRNA gene sequencing was performed on all samples. For resistome analysis, shotgun metagenomic sequencing was performed on selected samples. RESULTS: Hospitalisation without antimicrobial treatment did not significantly affect microbiota composition. Oral TMS treatment reduced alpha-diversity significantly. Kiritimatiellaeota, Fibrobacteres and Verrucomicrobia significantly decreased in relative abundance, whereas Firmicutes increased. The faecal microbiota composition gradually recovered after discontinuation of TMS treatment and discharge from the hospital and, after 2 weeks, was more similar to pre-treatment composition than to composition during TMS treatment. Six months later, however, microbiota composition still differed significantly from that at the start of the study and Spirochaetes and Verrucomicrobia were less abundant. TMS administration led to a significant (up to 32-fold) and rapid increase in the relative abundance of resistance genes sul2, tetQ, ant6-1a, and aph(3")-lb. lnuC significantly decreased directly after treatment. Resistance genes sul2 (15-fold) and tetQ (six-fold) remained significantly increased 6 months later. CONCLUSIONS: Oral treatment with TMS has a rapid and long-lasting effect on faecal microbiota composition and resistome, making the equine hindgut a reservoir and potential source of resistant bacteria posing a risk to animal and human health through transmission. These findings support the judicious use of antimicrobials to minimise long-term faecal presence, excretion and the spread of antimicrobial resistance in the environment. Video Abstract.202336850017
6944150.9873Rapidly mitigating antibiotic resistant risks in chicken manure by Hermetia illucens bioconversion with intestinal microflora. Antibiotic resistance genes (ARGs) in animal manure are an environmental concern due to naturally occurring bacteria being exposed to these wastes and developing multidrug resistance. The bioconversion of manure with fly larvae is a promising alternative for recycling these wastes while attenuating ARGs. We investigated the impact of black soldier fly (BSF, Hermetia illucens) larval bioconversion of chicken manure on the persistence of associated ARGs. Compared with traditional composting or sterile larval treatments (by 48.4% or 88.7%), non-sterile BSF larval treatments effectively reduced ARGs and integrin genes by 95.0% during 12 days, due to rapid decreases in concentrations of the genes and associated bacteria as they passed through the larval gut and were affected by intestinal microbes. After larval treatments, bacterial community composition differed significantly, with the percentage of Firmicutes possibly carrying ARGs reduced by 65.5% or more. On average, human pathogenic bacteria populations declined by 70.7%-92.9%, effectively mitigating risks of these bacteria carrying ARGs. Environmental pH, nitrogen content and antibiotic concentrations were closely related to both bacterial community composition and targeted gene attenuation in larval systems. Selective pressures of larval gut environments with intestinal microbes, larval bacteriostasis and reformulation of manure due to larval digestion contributed to ARG attenuation.201830318817
8072160.9873Response of microbial communities based on full-scale classification and antibiotic resistance genes to azithromycin and copper combined pollution in activated sludge nitrification laboratory mesocosms at low temperature. This study aimed to investigate the short-term response of abundant-rare genera and antibiotic resistance genes (ARGs) to azithromycin (AZM, 0.05-40 mg/L) and copper (1 mg/L) combined pollution in activated sludge nitrification system at low temperature. Nitrification was as expected inhibited in stress- and post-effects periods under AZM concentration higher than 5 mg/L. Abundant and rare taxa presented dissimilar responses based on full-scale classification. Conditionally rare or abundant taxa (CRAT) were keystone taxa. Relative abundance of ammonia-oxidizing archaea increased, and three aerobic denitrifying bacteria (Brevundimonas, Comamonas and Trichococcus) were enriched (from 9.83% to 68.91% in total). Ammonia nitrogen assimilating into Org-N and denitrification may be nitrogen pathways based on predict analysis. 29 ARGs were found with more co-occurrence patterns and high concentration of AZM (greater than 5 mg/L) caused their proliferation. Importantly, expect for some abundant taxa, rare taxa, potential pathogens and nitrogen-removal functional genera were the main potential hosts of ARGs.202134523571
6941170.9873Tertiary Wastewater Treatment Processes Can Be a Double-Edged Sword for Water Quality Improvement in View of Mitigating Antimicrobial Resistance and Pathogenicity. Despite the high removal efficiency for chemical pollutants by tertiary wastewater treatment processes (TWTPs), there is no definite conclusion in terms of microbial risk mitigation yet. This study utilized metagenomic approaches to reveal the alterations of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), their co-occurrence, and potential hosts during multiple TWTPs. Results showed that the TWTPs reduced chemical pollutants in wastewater, but the denitrifying biofilter (DB) significantly increased the absolute abundances of selected antibiotic-resistant bacteria and ARGs, and simultaneously elevated the relative abundances of ARGs and VFGs through the enrichment of multidrug resistance and offensive genes, respectively. Moreover, the co-occurrence of ARGs and VFGs (e.g., bacA-tapW, mexF-adeG) was only identified after the DB treatment and all carried by Pseudomonas. Then, the ultraviolet and constructed wetland treatment showed good complementarity for microbial risk reduction through mitigating antibiotic resistance and pathogenicity. Network and binning analyses showed that the shift of key operational taxonomic units affiliating to Pseudomonas and Acinetobacter may contribute to the dynamic changes of ARGs and VFGs during the TWTPs. Overall, this study sheds new light on how the TWTPs affect the antibiotic resistome and VFG profiles and what TWTPs should be selected for microbial risk mitigation.202336538014
6911180.9873Linking bacterial life strategies with the distribution pattern of antibiotic resistance genes in soil aggregates after straw addition. Straw addition markedly affects the soil aggregates and microbial community structure. However, its influence on the profile of antibiotic resistance genes (ARGs), which are likely associated with changes in bacterial life strategies, remains unclear. To clarify this issue, a soil microcosm experiment was incubated under aerobic (WS) or anaerobic (AnWS) conditions after straw addition, and metagenomic sequencing was used to characterise ARGs and bacterial communities in soil aggregates. The results showed that straw addition shifted the bacterial life strategies from K- to r-strategists in all aggregates, and the aerobic and anaerobic conditions stimulated the growth of aerobic and anaerobic r-strategist bacteria, respectively. The WS decreased the relative abundances of dominant ARGs such as QnrS5, whereas the AnWS increased their abundance. After straw addition, the macroaggregates consistently exhibited a higher number of significantly altered bacteria and ARGs than the silt+clay fractions. Network analysis revealed that the WS increased the number of aerobic r-strategist bacterial nodes and fostered more interactions between r-and K-strategist bacteria, thus promoting ARGs prevalence, whereas AnWS exhibited an opposite trend. These findings provide a new perspective for understanding the fate of ARGs and their controlling factors in soil ecosystems after straw addition. ENVIRONMENTAL IMPLICATIONS: Straw soil amendment has been recommended to mitigate soil fertility degradation, improve soil structure, and ultimately increase crop yields. However, our findings highlight the importance of the elevated prevalence of ARGs associated with r-strategist bacteria in macroaggregates following the addition of organic matter, particularly fresh substrates. In addition, when assessing the environmental risk posed by ARGs in soil that receives crop straw, it is essential to account for the soil moisture content. This is because the species of r-strategist bacteria that thrive under aerobic and anaerobic conditions play a dominant role in the dissemination and accumulation of ARG.202438643583
7008190.9873Pharmaceutical exposure changed antibiotic resistance genes and bacterial communities in soil-surface- and overhead-irrigated greenhouse lettuce. New classes of emerging contaminants such as pharmaceuticals, antibiotic resistant bacteria (ARB), and antibiotic resistance genes (ARGs) have received increasing attention due to rapid increases of their abundance in agroecosystems. As food consumption is a direct exposure pathway of pharmaceuticals, ARB, and ARGs to humans, it is important to understand changes of bacterial communities and ARG profiles in food crops produced with contaminated soils and waters. This study examined the level and type of ARGs and bacterial community composition in soil, and lettuce shoots and roots under soil-surface or overhead irrigation with pharmaceuticals-contaminated water, using high throughput qPCR and 16S rRNA amplicon sequencing techniques, respectively. In total 52 ARG subtypes were detected in the soil, lettuce shoot and root samples, with mobile genetic elements (MGEs), and macrolide-lincosamide-streptogramin B (MLSB) and multidrug resistance (MDR) genes as dominant types. The overall abundance and diversity of ARGs and bacteria associated with lettuce shoots under soil-surface irrigation were lower than those under overhead irrigation, indicating soil-surface irrigation may have lower risks of producing food crops with high abundance of ARGs. ARG profiles and bacterial communities were sensitive to pharmaceutical exposure, but no consistent patterns of changes were observed. MGE intl1 was consistently more abundant with pharmaceutical exposure than in the absence of pharmaceuticals. Pharmaceutical exposure enriched Proteobacteria (specifically Methylophilaceae) and decreased bacterial alpha diversity. Finally, there were significant interplays among bacteria community, antibiotic concentrations, and ARG abundance possibly involving hotspots including Sphingomonadaceae, Pirellulaceae, and Chitinophagaceae, MGEs (intl1 and tnpA_1) and MDR genes (mexF and oprJ).201931336252