Effects of Pyroligneous Acid on Diversity and Dynamics of Antibiotic Resistance Genes in Alfalfa Silage. - Related Documents




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696701.0000Effects 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
696610.9999Effects of Lactic Acid Bacteria Inoculants on Fermentation Quality, Bacteria Communities and Antibiotic Resistance Genes in Whole-Crop Corn Silage. Feed is an important source of antibiotic resistance genes (ARGs) in animals and products, posing significant potential risks to human health and the environment. Ensiling may present a feasible method for reducing ARGs in animal feed. This study involved the addition of four types of lactic acid bacteria (LAB) inoculants, Lactiplantibacillus plantarum (LP), Pediococcus acidilactici (P), Enterococcus faecium (E), and Ligilactobacillus salivarius (LS), to whole-crop corn silage to investigate changes in ARGs, mobile genetic elements (MGEs), and their transmission risks during ensiling. The results indicated that the addition of LAB significantly reduced the ammonia nitrogen content and pH value of whole-crop corn silage, inhibited the growth of harmful microorganisms, and increased the lactic acid content (p < 0.05). The improvement effect was particularly pronounced in the P treatment group. Natural fermentation plays a significant role in reducing ARG abundance, and the addition of different types of lactic acid bacteria helps reduce the abundance of both ARGs and MGEs. Specifically, the LS treatment group exhibited a significant decrease in MGE abundance, potentially reducing the horizontal transmission risk of ARGs. Furthermore, variations in ARG abundance within different LAB strains were detected, showing a consistent trend with that in silage. ARGs and MGEs were correlated with the fermentation parameters and microbial communities (p < 0.05). This suggests that adding LAB with low levels of ARGs to silage can effectively reduce ARG contamination. Bacterial community structure, MGEs, and fermentation quality may act as driving forces for the transfer and dissemination of ARGs in the silage ecosystem.202541011310
725720.9998Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes. Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P < 0.05), while those of genes encoding sulfonamide resistance (sul1 and sul2) were increased (P < 0.05) when normalized to 16S rRNA. The abundances of tetracycline resistance genes were correlated (P < 0.05) with the changing concentrations of tetracyclines in the manure. The overall diversity and richness of the bacteria significantly decreased during vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems.201526296728
696530.9998Metaphire guillelmi gut as hospitable micro-environment for the potential transmission of antibiotic resistance genes. Earthworm gut played an important role in the transformation of various contaminants in the soil environments. With the increasing application of organic fertilizer recently, the ingestion of antibiotics, antibiotic resistance bacteria (ARB), and antibiotic resistance genes (ARGs) made the earthworm gut a potential favorable micro-environment for the transmission of ARGs in the soil. In this work, the conventional plate incubation and high-throughput sequencing methods were both employed to investigate the composition of the cultivable and overall ARB/ARGs in the Metaphire guillelmi earthworm gut. A total of 87 cultivable isolates that resisted tetracycline (TC) and/or sulfadiazine (SD) were obtained, most of which belonged to phylum Firmicutes, genus Bacillus. Meanwhile, the counts of isolates with TC-SD dual resistance were higher than those with sole SD or TC resistance. Moreover, higher ARB counts and diversity were detected in the earthworm gut by high-throughput sequencing technique than those by the classical plate cultivation. Overall, the combination of conventional cultivable bacteria isolation and high-throughput sequencing methods provided a comprehensive understanding of the ARB composition in the earthworm gut. The results demonstrate that the earthworm gut is a hospitable micro-environment for ARB colonization. The potential role of earthworm intestinal ARB and ARGs proliferation in soil environments warrants further research.201930884260
695040.9998Ceftiofur in swine manure contributes to reducing pathogens and antibiotic resistance genes during composting. Aerobic composting is a common way for the disposal of feces produced in animal husbandry, and can reduce the release of antibiotic resistance genes (ARGs) from feces into the environment. In this study, we collected samples from two distinct treatments of swine manure compost with and without ceftiofur (CEF), and identified the ARGs, mobile genetic elements (MGEs), and bacterial community by metagenomic sequencing. The impacts of CEF on the bacterial community composition and fate of ARGs and MGEs were investigated. With increasing composting temperature and pH, the concentration of CEF in the manure decreased rapidly, with a degradation half-life of 1.12 d and a 100% removal rate after 10 d of aerobic composting. Metagenomics demonstrated that CEF in the manure might inhibit the growth of Firmicutes and Proteobacteria, thereby reducing some ARGs and MGEs hosted by these two bacteria, which was further confirmed by the variations of ARGs and MGEs. A further redundancy analysis suggested that pH and temperature are key environmental factors affecting ARG removal during composting, and intI1 and bacterial communities also have significant influence on ARG abundance. These results are of great significance for promoting the removal of some ARGs from animal manure by controlling some key environmental factors and the type of antibiotics used in animals.202438685300
694850.9997Fate of antibiotic resistance genes and metal resistance genes during the thermophilic fermentation of solid and liquid swine manures in an ectopic fermentation system. Environmental pollution due to resistance genes from livestock manure has become a serious issue that needs to be resolved. However, little studies focused on the removal of resistance genes in simultaneous processing of livestock feces and urine. This study investigated the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and class 1 integron-integrase gene (intI1) during thermophilic fermentation of swine manure in an ectopic fermentation system (EFS), which has been regarded as a novel system for efficiently treating both feces and urine. The abundances of MRGs and tetracycline resistance genes were 34.44-97.71% lower in the EFS. The supplementation of heavy metals significantly increased the abundance of intI1, with the enhancement effect of copper being more prominent than that of zinc. The highest abundances of resistance genes and intI1 were observed at high Cu levels (A2), indicating that Cu can increase the spreading of resistance genes through integrons. Network analysis revealed the co-occurrence of ARGs, MRGs, and intI1, and these genes potentially shared the same host bacteria. Redundancy analysis showed that the bacterial community explained most of the variations in ARGs, and environmental factors had influences on ARGs abundances by modulating the bacterial community composition. The decreased Sphingomonas, Comamonas, Acinetobacter, Lactobacillus, Bartonella, Rhizobium, and Bacteroides were mainly responsible for the reduced resistance genes. These results demonstrate that EFS can reduce resistance genes in simultaneous processing of livestock feces and urine.202133592372
759260.9997Incubation trial indicated the earthworm intestinal bacteria as promising biodigestor for mitigating tetracycline resistance risk in anthropogenic disturbed forest soil. The continuous input of antibiotics due to frequent anthropogenic activities have increased the dissemination risk of antibiotic resistance genes (ARGs) in forest soil. As soil engineers, it remains unclear whether earthworm intestinal microbial communities might play a role in controlling the ARG proliferation in forest soil. This study collected forest soil in the Yangtze River Delta, China, and its resident Metaphire guillelmi to investigate the interaction between tetracycline (50 μg kg(-1)) and the bacteria in worm gut and soil. Metagenome sequencing analysis indicated that the abundance of the total ARGs in both the soil (S2) and the worm gut (E2) was 1.3 (p < 0.001) and 1.2 (p < 0.001) times higher than the soil (S1) and (E1) without tetracycline exposure; and under tetracycline stress, the relative abundance of 36 and 20 bacterial genera in forest soil and worm gut were significantly increased respectively. However, the ARGs/ARB abundance decreased in the soil with the worm addition than that without, which may be related to the fact that earthworm intestinal bacteria harbored more tetracycline-degrading genes, i.e. dehydrogenase genes adh, ETFDH, and gpr, etc. Structural equation model analysis indicated that bacteria in worm intestinal has stronger ability to degrade tetracycline than in soil, and the main dissipate way was dehydrogenation. Together, the results contributed to understanding the promising role of worm intestinal bacteria in controlling the ARG risk caused by antibiotic disturbed forest soil.202134340069
807870.9997Responses of bacterial communities and resistance genes on microplastics to antibiotics and heavy metals in sewage environment. In present study, copper (Cu), zinc (Zn), tetracycline (TC) and ampicillin (AMP) were selected to study the individual and synergistic effects of antibiotics and heavy metals on the microbial communities and resistance genes on polyvinyl chloride microplastics (PVC MPs) and surrounding sewage after 28 and 84 days. The results indicated that PVC MPs enriched many microorganisms from surrounding sewage, especially pathogenic bacteria such as Mycobacterium and Aquabacterium. The resistance gene with the highest abundance enriched on PVC MPs was tnpA (average abundance of 1.0 × 10(7) copies/mL sewage). The single presence of Zn, TC and AMP inhibited these enrichments for a short period of time (28 days). But the single presence of Cu and the co-existence of antibiotics and heavy metals inhibited these enrichments for a long period of time (84 days), resulting in relatively low microbial diversities and resistance genes abundances. Transpose tnpA had significantly positive correlations (p < 0.05) with all other genes. Pathogenic bacteria Mycobacterium and Legionella were potential hosts harboring 5 and 1 resistance genes, respectively. Overall, PVC MPs played important roles in the distribution and transfer of pathogenic bacteria and resistance genes in sewage with the presence of antibiotics or (and) heavy metals.202133254740
694580.9997Mitigation 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
704790.9997Characteristics of airborne bacterial communities and antibiotic resistance genes under different air quality levels. Pathogenic bacteria and antibiotic resistance genes (ARGs) in bioaerosols are major threats to human health. In this study, the microbial community structure and ARG distribution characteristics of airborne bacteria in total suspended particulates (TSP) and PM(2.5) were investigated under different air quality levels in Xinxiang, Central China. The results revealed that with the deterioration of air quality, the concentrations of airborne bacteria in both TSP and PM(2.5) decreased; however, the relative amounts of pathogenic bacteria increased. The predominant genera in pathogenic bacteria of Bacillus, Sphingomonas, Corynebacterium, Rhodococcus, and Staphylococcus were identified in both TSP and PM(2.5). Although the airborne bacteria concentrations and absolute abundances of ARGs in TSP were higher than those in PM(2.5) under identical air quality conditions, the bacterial community structure and relative amounts of pathogenic bacteria were similar. In addition, the relationship between environmental factors of ions, metal elements, and meteorological parameters and the community structures of airborne bacteria and pathogenic bacteria were also analyzed. The effects of soluble ions and metal elements on several dominant genera of total bacteria and pathogenic bacteria differed, probably due to the strong tolerance of pathogenic bacteria to harsh atmospheric environments Different subtypes of ARGs showed various distribution characteristics with variations in air quality. The deterioration of air quality can inhibit the dissemination of ARGs, as the minimum values of all ARGs and class 1 integrase intI1 were observed under Severely Polluted conditions. This study provides a comprehensive understanding of the effect of air pollution levels on the airborne bacteria community composition and ARG distribution.202235180669
6949100.9997Tracing the transfer characteristics of antibiotic resistance genes from swine manure to biogas residue and then to soil. Based on laboratory simulation experiments and metagenomic analysis, this study tracked the transmission of antibiotic resistance genes (ARGs) from swine manure (SM) to biogas residue and then to soil (biogas residue as organic fertilizer (OF) application). ARGs were abundant in SM and they were assigned to 11 categories of antibiotics. Among the 383 ARG subtypes in SM, 43 % ARG subtypes were absent after anaerobic digestion (AD), which avoided the transfer of these ARGs from SM to soil. Furthermore, 9 % of the ARG subtypes in SM were introduced into soil after amendment with OF. Moreover, 43 % of the ARG subtypes in SM were present in OF and soil, and their abundances increased slightly in the soil amended with OF. The bacterial community in the soil treated with OF was restored to its original state within 60 to 90 days, probably because the abundances of ARGs were elevated but not significantly in the soil. Network analysis identified 31 potential co-host bacteria of ARGs based on the relationships between the bacteria community members, where they mainly belonged to Firmicutes, followed by Bacteroidetes, Actinobacteria, and Proteobacteria. This study provides a basis for objectively evaluating pollution by ARGs in livestock manure for agricultural use.202438072280
8079110.9997Response of antibiotic resistance to the co-exposure of sulfamethoxazole and copper during swine manure composting. Heavy metals driven co-selection of antibiotic resistance in soil and water bodies has been widely concerned, but the response of antibiotic resistance to co-existence of antibiotics and heavy metals in composting system is still unknown. Commonly used sulfamethoxazole and copper were individually and jointly added into four reactors to explore their effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), heavy metal resistance genes (MRGs) and bacterial community structure. The abundance of total ARGs and MGEs were notably decreased by 68.64%-84.95% and 91.27-97.38%, respectively, after the composting. Individual addition of sulfamethoxazole, individual addition of copper, simultaneously addition of sulfamethoxazole and copper increased the abundance of ARGs and MGEs throughout the composting period. Co-exposure of sulfamethoxazole and copper elevated the total abundance of ARGs by 1.17-1.51 times by the end of the composting compared to individual addition of sulfamethoxazole or copper. Network analysis indicated that the shifts in potential host bacteria determined the ARGs variation. Additionally, MGEs and MRGs had significant effects on ARGs, revealing that horizontal gene transfer and heavy metals induced co-resistance could promote ARGs dissemination.202234537705
8024120.9997High 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
7411130.9997Thermophilic Composting of Human Feces: Development of Bacterial Community Composition and Antimicrobial Resistance Gene Pool. In times of climate change, practicing sustainable, climate-resilient, and productive agriculture is of primordial importance. Compost from different resources, now treated as wastes, could be one form of sustainable fertilizer creating a resilience of agriculture to the adverse effects of climate change. However, the safety of the produced compost regarding human pathogens, pharmaceuticals, and related resistance genes must be considered. We have assessed the effect of thermophilic composting of dry toilet contents, green cuttings, and straw, with and without biochar, on fecal indicators, the bacterial community, and antibiotic resistance genes (ARGs). Mature compost samples were analyzed regarding fecal indicator organisms, revealing low levels of Escherichia coli that are in line with German regulations for fertilizers. However, one finding of Salmonella spp. exceeded the threshold value. Cultivation of bacteria from the mature compost resulted in 200 isolates with 36.5% of biosafety level 2 (BSL-2) species. The majority is known as opportunistic pathogens that likewise occur in different environments. A quarter of the isolated BSL-2 strains exhibited multiresistance to different classes of antibiotics. Molecular analysis of total DNA before and after composting revealed changes in bacterial community composition and ARGs. 16S rRNA gene amplicon sequencing showed a decline of the two most abundant phyla Proteobacteria (start: 36-48%, end: 27-30%) and Firmicutes (start: 13-33%, end: 12-16%), whereas the abundance of Chloroflexi, Gemmatimonadetes, and Planctomycetes rose. Groups containing many human pathogens decreased during composting, like Pseudomonadales, Bacilli with Bacillus spp., or Staphylococcaceae and Enterococcaceae. Gene-specific PCR showed a decline in the number of detectable ARGs from 15 before to 8 after composting. The results reveal the importance of sufficiently high temperatures lasting for a sufficiently long period during the thermophilic phase of composting for reducing Salmonella to levels matching the criteria for fertilizers. However, most severe human pathogens that were targeted by isolation conditions were not detected. Cultivation-independent analyses also indicated a decline in bacterial orders comprising many pathogenic bacteria, as well as a decrease in ARGs. In summary, thermophilic composting could be a promising approach for producing hygienically safe organic fertilizer from ecological sanitation.202235250940
6902140.9997Antibiotic resistance genes in surface water and groundwater from mining affected environments. Mining activities are known to generate a large amount of mine tailings and acid mine drainage which contain varieties of heavy metals. Heavy metals play an important role in co-selection for bacterial antibiotic resistance. However, the characteristics of antibiotic resistance genes (ARGs) in mining-affected water environments are still unclear. Here we investigated the pollution of metals, profiles of ARGs, mobile genetic elements (MGEs) and microbial community in mining-affected surface water and groundwater. The results showed that in the tested water samples, the concentrations of Zn and Mn were the highest, and Ni was the lowest. Higher abundances of ARGs with great proportion of sulfonamides, chloramphenicols and tetracyclines resistance genes were found in mining-affected water when compared with those without mining activities. Additionally, there were positive correlations between heavy metals (especially Ni, Zn and Mn) and these ARGs. Linear regression analysis suggested that MGEs were positively correlated with ARGs. In addition, total phosphorus was correlated with ARGs (p < 0.05). The microbial community was different between the mining-affected water and the reference (p < 0.05). Proteobacteria, Bacteroidetes and Actinobacteria were dominant phyla in the surface water and groundwater. Network analysis showed that many ARGs were significantly associated with these dominant bacteria, which suggested they might be potential hosts for these ARGs. These findings provide a clear evidence that the mining activities in the study area had a significant impact on surface water and groundwater to different degrees.202133571766
8091150.9997Changes in antibiotic resistance genes and mobile genetic elements during cattle manure composting after inoculation with Bacillus subtilis. This study explored the effects of Bacillus subtilis at four levels (0, 0.5%, 1%, and 2% w/w compost) on the variations in ARGs, mobile genetic elements (MGEs), and the bacterial community during composting. The composting process had a greater impact on ARGs than Bacillus subtilis. The main ARG detected was sul1. The addition of Bacillus subtilis at 0.5% reduced the relative abundances of ARGs, MGEs, and human pathogenic bacteria (by 2-3 logs) in the mature products. Network and redundancy analyses suggested that intI1, Firmicutes, and pH were mainly responsible for the changes in ARGs, thus controlling these factors might help to inhibit the spread of ARGs.201931442833
6951160.9997The vertical migration of antibiotic-resistant genes and pathogens in soil and vegetables after the application of different fertilizers. The prevalence of bacterial resistance caused by the application of animal manure has become an important environmental issue. Herein, the vertical migration of antibiotic resistance genes (ARGs) and pathogens in soil and vegetables after the application of different fertilizers was explored. The results showed that the application of composted manure considerably enhanced the abundance of most ARGs and pathogens, especially in surface soil and pakchoi roots. Moreover, the soil ARGs increased partially from log 1.93 to log 4.65 after the application of composted manure, and six pathogens were simultaneously detected. It was observed that the increase in soil depth decreased most ARGs and pathogens by log 1.04-2.24 and 53.98 %~85.54 %, respectively. This indicated that ARGs and pathogens still existed in the deep soil (80-100 cm). Moreover, total organic carbon had a significant influence on the pathogen distribution, whereas bacterial communities primarily drove the vertical migration of ARGs rather than environmental factors. Although most of the ARG-host associations observed in the surface soil were disappeared in deep soil as revealed by network analysis, some co-occurrence pattern still occurred in deep soil, suggesting that some ARGs might be carried to deep soil by their host bacteria. These results were novel in describing the vertical migration of ARGs in the environment after the application of different fertilizers, providing ideas for curbing their migration to crops.202234400159
8086170.9997Biofilm enhanced the mitigations of antibiotics and resistome in sulfadiazine and trimethoprim co-contaminated soils. Reducing antibiotic levels in soil ecosystems is vital to curb the dissemination of antimicrobial resistance genes (ARGs) and mitigate global health threats. However, gaps persist in understanding how antibiotic resistome can be suppressed during antibiotic degradation. Herein, we investigate the efficacy of a biochar biofilm incorporating antibiotics-degrading bacterial strain (Arthrobacter sp. D2) to mitigate antibiotic resistome in non-manured and manure-amended soils with sulfadiazine (SDZ) and trimethoprim (TMP) contamination. Results show that biofilm enhanced SDZ degradation by 83.0% within three days and increased TMP attenuation by 55.4% over 60 days in non-manured soils. In the non-manured black soil, the relative abundance of ARGs increased initially after biofilm inoculation. However, by day 30, it decreased by 20.5% compared to the controls. Moreover, after 7 days, biofilm reduced TMP by 38.5% in manured soils and decreased the total ARG abundance by 19.0%. Thus, while SDZ degradation did not increase sulfonamide resistance genes, TMP dissipation led to a proliferation of insertion sequences and related TMP resistance genes. This study underscores the importance of antibiotic degradation in reducing related ARGs while cautioning against the potential proliferation and various ARGs transfer by resistant microorganisms.202439255667
8090180.9997Swine Manure Composting With Compound Microbial Inoculants: Removal of Antibiotic Resistance Genes and Their Associations With Microbial Community. In this study, compound microbial inoculants, including three Bacillus strains and one Yeast strain, were inoculated into swine manure composting to explore the effects on antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), microbial community structure, and pathogenic bacteria. The results indicated that the abundances of the detected ARGs ranged from 3.6 × 10(3) to 1.13 × 10(8) copies/g. The ARGs with the highest abundance was sul2, and the lowest was blaCTX. Composting removes most of the ARGs and MGEs by 22.8-99.7%. These ARGs were significantly reduced during the thermophilic phase of compost. The removal rate of ARGs at the different layers of compost pile was different as follows: middle layer > upper layer > lower layer. But some ARGs proliferated significantly in the maturation phase of compost, especially the sulfonamide resistance genes. Compound microbial inoculants increased the temperature of compost, accelerated water loss, nitrogen fixation, and increased the removal rate of β-lactamase resistance genes, the transposon gene tn916 and part of tetracycline resistance genes by 3.7-23.8% in compost. Compound microbial inoculants changed the community structure and increased the Bacillus abundance in the thermophilic phase of compost. And it was helpful for removing pathogens during composting. The addition of compound microbial inoculants causes the decrease of Firmicutes and the increase of Bacteroidetes, which may be related to the removal and proliferation of ARGs.202033250880
7415190.9997Transfer and accumulation of antibiotic resistance genes and bacterial pathogens in the mice gut due to consumption of organic foods. Over the last few decades, organic food demand has grown largely because of increasing personal health concerns. Organic farming introduces antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) into foods. However, potential effects of organic foods on the gut microbiome and ARGs have been overlooked. Using high-throughput quantitative PCR and 16S rRNA high-throughput sequencing technology, we examined 132 ARGs from major classes, eight transposase genes, universal class I integron-integrase gene (intI), clinical class I integron-integrase gene (cintI), and the bacterial community in mouse gut after 8 weeks with an either organic or inorganic lettuce and wheat diet. A total of 8 types of major ARGs and 10 mobile genetic elements (MGEs) were detected in mice gut, including tetracycline, multidrug, sulfonamide, aminoglycoside, beta-lactamase, chloramphenicol, MLSB and vancomycin resistance genes. We found that abundance and diversity of ARGs, mobile gene elements, and potential ARB in the gut increased with time after consumption of organic foods, whereas no significant changes were observed in inorganic treated groups. Moreover, MGEs, including IS613, Tp614 and tnpA_03 were found to play an important role in regulating ARG profiles in the gut microbiome following consumption of organic foods. Importantly, feeding organic food increased the relative abundance of the potentially antibiotic-resistant pathogens, Bacteroides and Streptococcus. Our results confirm that there is an increasing risk of ARGs and ARB in the gut microbiome, which highlights the importance of organic food industries taking into account the potential accumulation and transmission of ARGs as a risk factor.202438215844