# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 8017 | 0 | 1.0000 | Dose-Dependent Effect of Tilmicosin Residues on ermA Rebound Mediated by IntI1 in Pig Manure Compost. The impact of varying antibiotic residue levels on antibiotic resistance gene (ARG) removal during composting is still unclear. This study investigated the impact of different residue levels of tilmicosin (TIM), a common veterinary macrolide antibiotic, on ARG removal during pig manure composting. Three groups were used: the CK group (no TIM), the L group (246.49 ± 22.83 mg/kg TIM), and the H group (529.99 ± 16.15 mg/kg TIM). Composting removed most targeted macrolide resistance genes (MRGs) like ereA, ermC, and ermF (>90% removal), and reduced ermB, ermX, ermQ, acrA, acrB, and mefA (30-70% removal). However, ermA increased in abundance. TIM altered compost community structure, driving succession through a deterministic process. At low doses, TIM reduced MRG-bacteria co-occurrence, with horizontal gene transfer via intI1 being the main cause of ermA rebound. In conclusion, composting reduces many MRG levels in pig manure, but the persistence and rebound of genes like ermA reveal the complex interactions between composting conditions and microbial gene transfer. | 2025 | 41011454 |
| 8021 | 1 | 0.9997 | The profile of antibiotic resistance genes in pig manure composting shaped by composting stage: Mesophilic-thermophilic and cooling-maturation stages. The variation of antibiotic resistance genes (ARGs) and influential factors in pig manure composting were investigated by conducting simulated composting tests using four different supplement materials (wheat straw, corn straw, poplar sawdust and spent mushroom). The results show that the relative abundance of total ARGs increased by 0.19-1.61 logs after composting, and tetX, sulI, sulII, dfrA1 and aadA were the major contributors. The variations of ARG profiles and bacterial communities throughout the composting were clearly divided into mesophilic-thermophilic and cooling-maturation stages in all tests, while different supplement materials did not exert a noticeable influence. Network analysis demonstrated the diversity of bacterial hosts for ARGs, the existence of multiple antibiotic resistant bacteria, and the weak correlations between ARGs and physicochemical factors in the composting piles. Of note, integron intI1 and Mycobacterium (a potential pathogen) were positively correlated with eight and four ARGs, respectively, that displayed increased abundance after composting. | 2020 | 32109697 |
| 8075 | 2 | 0.9997 | Exploring the impact of biochar on antibiotics and antibiotics resistance genes in pig manure aerobic composting through untargeted metabolomics and metagenomics. This study investigated the effect of biochar on antibiotics and antibiotic resistance genes (ARGs) during aerobic composting of pig manure. First, the composition and content of antibiotics in the manure were determined qualitatively and quantitatively. Biochar promoted the degradation of these antibiotics (oxytetracycline, chlortetracycline, and tetracycline). The relative abundance (RA) of antibiotic-resistant bacteria carrying ARGs accounted for about 29.32% of the total bacteria. Firmicutes and Actinomycetes were dominant phylum-level bacteria at the early and late stages of composting, respectively. Biochar decreased the total RA of ARGs by 16.83%±4.10%. tetW and tetL, closely related to tetracycline resistance, were significantly diminished during aerobic composting, and biochar was able to promote this removal. Biochar enhanced RAs of Mycobacterium tuberculosis kasA mutant. RAs of ARGs related to antibiotic efflux pumps, such as baeS and arlS, remained at a high level. Conclusively, biochar promotes degradation of antibiotics and removal of ARGs. | 2022 | 35398213 |
| 8019 | 3 | 0.9997 | In-feed antibiotic use changed the behaviors of oxytetracycline, sulfamerazine, and ciprofloxacin and related antibiotic resistance genes during swine manure composting. The dynamics of oxytetracycline (OTC), sulfamerazine (SM1), ciprofloxacin (CIP) and related antibiotic resistance genes (ARGs) during swine manure composting were compared between manure collected from swine fed a diet containing these three antibiotics (T(D)) and manure directly spiked with these drugs (T(S)). The composting removal efficiency of OTC (94.9 %) and CIP (87.8 %) in the T(D) treatment was significantly higher than that of OTC (83.8 %, P < 0.01) and CIP (83.9 %, P < 0.05) in the T(S) treatment, while SM1 exhibited no significant difference (P > 0.05) between the two treatments. Composting effectively reduced the majority of ARGs in both T(D) and T(S) types of manure, especially tetracycline resistance genes (TRGs). Compared with the T(S) treatment, the abundance of some ARGs, such as tetG, qepA, sul1 and sul2, increased dramatically up to 309-fold in the T(D) treatment. The microbial composition of the composting system changed significantly during composting due to antibiotic feeding. Redundancy analysis suggested that the abundance of ARGs had a considerable impact on alterations in the physicochemical parameters (C/N, pH and temperature) and bacterial communities (Actinobacteria, Proteobacteria and Firmicutes) during the composting of swine manure. | 2021 | 33254754 |
| 8090 | 4 | 0.9996 | Swine 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. | 2020 | 33250880 |
| 8018 | 5 | 0.9996 | Analysis for microbial denitrification and antibiotic resistance during anaerobic digestion of cattle manure containing antibiotic. This study investigated the effects of tylosin (0, 10, and 100 mg/kg dry weight) on the denitrification genes and microbial community during the anaerobic digestion of cattle manure. N(2) emissions were reduced and N(2)O emissions were increased by 10 mg/kg tylosin. Adding 100 mg/kg tylosin increased the emission of both N(2)O and N(2). The different responses of denitrifying bacteria and genes to tylosin may have been due to the presence of antibiotic resistance genes (ARGs). Network analysis indicated that denitrification genes and ARGs had the same potential host bacteria. intI1 was more important for the horizontal transfer of denitrification genes and ARGs during anaerobic digestion than intI2. The anaerobic digestion of manure containing tylosin may increase nitrogen losses and the associated ecological risk. | 2019 | 31326686 |
| 8023 | 6 | 0.9996 | Effects of macroporous adsorption resin on antibiotic resistance genes and the bacterial community during composting. Swine manure is considered a reservoir for antibiotic resistance genes (ARGs), which may enter the soil and then the food chain to endanger human health. This study investigated the effects of adding 0%, 5%, and 15% (w/w) macroporous adsorption resin (MAR) on ARGs and the bacterial community during composting. The results showed that the addition of MAR reduced the abundances of ARGs (14.14-99.44%) and mobile genetic elements (MGEs) (47.83-99.48%) after swine manure composting. Significant positive correlations were detected between ARGs and MGEs, and thus the variations in MGEs may have led to the changes in ARGs. Redundancy analysis showed that MGEs had stronger effects on ARGs than environmental factors and the bacterial community. Network analysis suggested that ARGs and MGEs co-existed in common host bacteria. In conclusion, the results showed that adding 5% MAR can reduce the risk of ARG transmission. | 2020 | 31634802 |
| 8022 | 7 | 0.9996 | Enrichment of antibiotic resistance genes after sheep manure aerobic heap composting. In this study, physio-chemical properties, 45 antibiotics, 6 heavy metals, 42 antibiotic resistance genes (ARGs), 3 mobile genetic elements, and the bacterial community structure were investigated to analyze the fate of ARGs during sheep manure aerobic heap composting. Results showed that sheep manure heap composting could produce mature compost. The degradation processes reduced the total antibiotics content by 85%. The abundance of ARGs and mobile genetic elements (MGEs) were enriched 9-fold, with the major increases to sul and tet genes (sulI, sulII, tetQ, and tetX). Tetracycline and sulfonamide resistance genes were the most abundant ARGs after composting (more than 88% of all genes). The genes tetA, tetX and sulI were related to the most diverse bacteria that were most able to proliferate during heap composting. Therefore, sulI and tetX are the major ARGs to be controlled, and Actinobacteria and Bacteroidetes may be the major host bacteria. | 2021 | 33429314 |
| 8100 | 8 | 0.9996 | Composting temperature directly affects the removal of antibiotic resistance genes and mobile genetic elements in livestock manure. The high antibiotic resistance gene (ARGs) contents in livestock manure pose a potential risk to environment and human health. The heap composting with an ambient temperature and thermophilic composting are two methods for converting livestock manure into fertilizer. This study investigated the variations in ARGs and mobile genetic elements (MGEs) and revealed potential mechanisms for ARGs removal using the two composting methods. The ARGs abundance were enriched by 44-fold in heap composting, among them, the macrolide-resistance genes increased significantly. On the contrary, the ARGs were removed by 92% in thermophilic composting, among them, tetracycline-resistance genes decreased by 97%. The bacterial hosts of ARGs were associated with the variations of ARGs and MGEs. The tetO was correlated with the most diverse bacteria in heap composting, and Bacteroidetes was the major host bacteria. While tetT was correlated with the most diverse bacteria in thermophilic composting, and Proteobacteria was the major host bacteria. Structural equation models showed that the enrichment of ARGs in heap composting was mainly correlated with bacterial communities, whereas, the removal of ARGs in thermophilic composting was directly affect by MGEs. Composting temperature directly affected the variations in ARGs. Higher and lower temperatures significantly decreased and increased, respectively, ARGs and MGEs abundance levels. | 2022 | 35306090 |
| 8011 | 9 | 0.9996 | Co-selective Pressure of Cadmium and Doxycycline on the Antibiotic and Heavy Metal Resistance Genes in Ditch Wetlands. Abuse of heavy metals and antibiotics results in the dissemination of metal resistance genes (MRGs) and antibiotic resistance genes (ARGs). Ditch wetlands are important sinks for heavy metals and antibiotics. The relationships between bacterial communities and MRG/ARG dissemination under dual stresses of heavy metals and antibiotics remain unclear. The responses of MRGs and ARGs to the co-selective pressure of cadmium (Cd) and doxycycline (DC) in ditch wetlands were investigated after 7-day and 84-day exposures. In ecological ditches, residual rates of Cd and DC varied from 0.4 to -5.73% and 0 to -0.61%, respectively. The greatest total relative abundance of ARGs was observed in the Cd 5 mg L(-1) + DC 50 mg L(-1) group. A significant level of DC (50 mg L(-1)) significantly reduced the total relative abundances of MRGs at a concentration of 5 mg L(-1) Cd stress. Redundancy analysis indicated that Cd and DC had strong positive effects on most ARGs and MRGs after a 7-day exposure. Meanwhile, the class 1 integron gene (intI1) exhibited strong positive correlations with most ARGs and cadmium resistance genes (czcA) after an 84-day exposure. Network analysis showed that Acinetobacter and Pseudomonas were the potential dominant host genera for ARGs and MRGs, and tetracycline resistance genes (tetA), czcA, and intI1 shared the same potential host bacteria Trichococcus after an 84-day exposure. | 2022 | 35250936 |
| 8025 | 10 | 0.9996 | Effect of temperature on sulfonamide antibiotics degradation, and on antibiotic resistance determinants and hosts in animal manures. Animal manure is a main reservoir of antibiotic residues and antibiotic resistance. Here, the effect of temperature on sulfonamide antibiotics (SAs), sulfonamide-resistant (SR) genes/bacteria was investigated by aerobically incubating swine and chicken manures at different temperatures. In swine manure, the SAs concentration declined with increasing temperature, with a minimum at 60°C. In chicken manure, the greatest degradation of SAs was noted at 30°C. The reduction of relative abundance of antibiotic resistance genes (ARGs) and sul-positive hosts in swine manure was more pronounced during thermophilic than mesospheric incubation; neither temperature conditions effectively reduced these parameters in chicken manure. The relationship between the residual levels/distribution profiles of SAs, ARGs (sul1, sul2 and intI1), cultivable SR bacteria and sul-positive hosts was further established. The antibiotic residual profile, rather than antibiotic concentration, acted as an important factor in the prevalence of ARGs and sul-positive hosts in manure. Corynebacterium and Leucobacter from the phylum Actinobacteria tend to be main carriers of sul1 and intI1; the relative abundance of sul2 was significantly correlated with the relative abundance of cultivable SR bacteria. Overall, differences in resistant bacterial communities also constitute a dominant factor affecting ARG variation. This study contributes to management options for reducing the pollution of antibiotics and antibiotic resistance within manure. | 2017 | 28711002 |
| 8020 | 11 | 0.9996 | Influence of zeolite and superphosphate as additives on antibiotic resistance genes and bacterial communities during factory-scale chicken manure composting. Factory-scale chicken manure composting added with zeolite (F), superphosphate (G), or zeolite and ferrous sulfate (FL) simultaneously, were evaluate for their effects on the behaviors of antibiotic resistance genes (ARGs) and bacterial communities. After composting, ARGs in manure decreased by 67.3% in the control, whereas the reductions were 86.5%, 68.6% and 72.2% in F, G and FL, respectively. ARGs encoding ribosomal protection proteins (tetO, tetB(P), and tetM) were reduced to a greater extent than tetG, tetL, sul1 and sul2. Bacteria pathogens were also effectively removed by composting. Network analysis showed that Firmicutes were the important potential host bacteria for ARGs. The bacterial communities and environmental factors, as well as the intI gene, contributed significantly to the variation of ARGs. The ARGs and integrons were reduced more when zeolite was added than when superphosphate was added; thus, it may be useful for reducing the risks of ARGs in chicken manure. | 2018 | 29772500 |
| 7998 | 12 | 0.9996 | Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms. The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p < 0.01), and both tetG and ereA increased after wastewater treatment. This may pose a great threat to public health. | 2017 | 26715413 |
| 8015 | 13 | 0.9996 | Distribution, horizontal transfer and influencing factors of antibiotic resistance genes and antimicrobial mechanism of compost tea. Compost tea was alternatives of chemical pesticide for green agriculture, but there were no reports about antibiotic resistance genes (ARGs) in compost tea. This study investigated the effect of livestock manures, sewage sludge, their composting products and liquid fermentation on ARGs, mobile genetic elements (MGEs), metal resistance genes (MRGs) and antimicrobial properties of various compost tea. The results showed aerobic liquid fermentation reduced ARGs by 65.93 % and 45.20 % in the compost tea of chicken manure and sludge, enriched ARGs by 8.57 % and 37.41 % in the compost tea of pig manure and bovine manure, and increased MGEs and MRGs by 1.25 × 10(-5)-5.53 × 10(-3) and 2.03 × 10(-5)-2.03 × 10(-3) in the four compost tea. The correlation coefficient of tetracycline and sulfonamide resistance genes between compost product and compost tea were 0.98 and 0.91. aadA2-02, sul2 and tetX abundant in the compost tea were positively correlated with MGEs and MRGs. Furthermore, liquid fermentation enriched the potential host of tetracycline and vancomycin resistance genes. Tetracycline resistance genes occupied 62.7 % of total ARGs in the compost tea. Alcaligenes and Bacillus enriched by 0.78-39.31 % in the four compost tea, which metabolites had high antimicrobial activity. The potential host of ARGs accounted for 42.1 % bacteria abundance in the four compost tea. | 2022 | 35803190 |
| 8026 | 14 | 0.9996 | A comparison of antibiotics, antibiotic resistance genes, and bacterial community in broiler and layer manure following composting. Animal manure is an important source of antibiotics and antibiotic resistance genes (ARGs) in the environment. However, the difference of antibiotic residues and ARG profiles in layer and broiler manure as well as their compost remains unexplored. In this study, we investigated the profiles of twelve antibiotics, seventeen ARGs, and class 1 integrase gene (intI1) in layer and broiler manure, and the corresponding compost at large-scale. Compared with layer manure, broiler manure exhibited approximately six times more residual tetracyclines, especially chlortetracycline. The relative abundances of qnrS and ermA genes in broiler manure were significantly higher than those in layer manure. The concentration of tetracyclines not only had a significantly positive correlation with tetracycline resistance genes (tetA and tetC) but was also positively correlated with quinolone resistance (qepA, qnrB, and qnrS) and macrolide resistance (ermA and ermT). Most ARGs in manure were reduced after composting. However, the relative abundance of sulfonamide resistance gene sul1 increased up to 2.41% after composting, which was significantly higher than that of broiler (0.41%) and layer (0.62%) manure. The associated bacterial community was characterized by high-throughput 16S rRNA gene sequencing. The relative abundances of thermophilic bacteria had significant positive correlations with the abundance of sul1 in compost. The composting has a significant impact on the ARG-associated gut microbes in poultry manure. Variation partitioning analysis indicated that the change of bacterial community compositions and antibiotics contributed partially to the shift in ARG profiles. The results indicate that at industry-scale production broiler manure had more antibiotics and ARGs than layer manure did, and composting decreased most ARG abundances in poultry manure except for sulfonamide resistance genes. | 2021 | 33219508 |
| 8091 | 15 | 0.9996 | Changes 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. | 2019 | 31442833 |
| 8014 | 16 | 0.9995 | Contributions of the microbial community and environmental variables to antibiotic resistance genes during co-composting with swine manure and cotton stalks. Understanding the main drivers that affect the spread of antibiotic resistance genes (ARGs) during the composting process is important for the removal of ARGs. In this study, three levels of tylosin (25, 50, and 75 mg kg(-1) on a dry weight basis) were added to swine manure plus a control, which was composted with cotton stalks. Each treatment was repeated in triplicate and the ARG profiles were determined with different levels of tylosin. The top 35 genera and ARGs profiles were clustered together based on the composting time. Combined composting parameters (temperature, pH, NH(4)(+)-N, NO(3)-N, and moisture content) accounted for 78.4% of the total variation in the changes in the potential host bacteria. In addition, the selected five composting parameters and six phyla (including 25 potential host bacterial genera) explained 46.9% and 30.7% of the variation in the ARG profiles according to redundancy analysis, respectively. The variations in ARGs during the composting process were mainly affected by the dynamics of potential host bacteria rather than integrons and the selective pressure due to bio-Cu and bio-Zn. | 2018 | 29990821 |
| 8024 | 17 | 0.9995 | High 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. | 2024 | 39795013 |
| 8062 | 18 | 0.9995 | Nanoscale zero-valent iron inhibits the horizontal gene transfer of antibiotic resistance genes in chicken manure compost. Livestock manure has been identified as a significant hotspot for antibiotic resistance genes (ARGs). However, the impact of nanoscale zero-valent iron (nZVI) on the fate of ARGs during livestock manure composting remains poorly understood. Here, we investigated the evolution of ARGs in chicken manure compost exposed to 100 and 600 mg kg(-1) nZVI. The results showed that nZVI addition reduced the concentration of some antibiotics such as doxycycline and sulfamethoxazole. Furthermore, nZVI addition decreased the abundances of most ARGs at the end of composting, but nZVI dosage did not have any significant effect. The abundances of the dominant ARGs (sul1 and sul2) were significantly correlated to the class 1 integron-integrase gene (intI1). A network analysis revealed that the genera Bacteroides, Bacillus, Corynebacterium, Thiopseudomonas and Pseudomonas were the main potential hosts for multiple ARGs, and the decreased abundance of these bacteria contributed to the removal of ARGs. Structural equation models demonstrated that the reduction in intI1 played a predominant role in ARG removal. The nZVI also had direct effects on the intI1 abundance. These findings suggest that the addition of nZVI is a promising strategy to minimize ARG release in chicken manure compost. | 2022 | 34416685 |
| 8096 | 19 | 0.9995 | Effects of biochar on reducing the abundance of oxytetracycline, antibiotic resistance genes, and human pathogenic bacteria in soil and lettuce. Antibiotics and antibiotic resistance genes (ARGs) in soil can affect human health via the food chain. Biochar is a soil amendment but its impacts on ARGs and the microbial communities associated with soil and vegetables are unclear. Therefore, we established three lettuce pot culture experiments, i.e., O300: 300 mg/kg oxytetracycline (OTC), BO300: 300 mg/kg OTC + 2% biochar, and a control without OTC or biochar. We found that under BO300, the relative abundances of ARGs were reduced by 51.8%, 43.4%, and 44.1% in lettuce leaves, roots, and soil, respectively, compared with O300. intI1 was highly abundant in soil and lettuce, and it co-occurred with some ARGs (tetW, ermF, and sul1). Redundancy analysis and network analysis indicated that the bacterial community succession was the main mechanism that affected the variations in ARGs and intI1. The reduction of Firmicutes due to the biochar treatment of soil and lettuce was the main factor responsible for the removal of tetracycline resistance genes in leaves. Biochar application led to the disappearance of human pathogenic bacteria (HPB), which was significantly correlated with the abundances of ermF and ermX. In summary, biochar is an effective farmland amendment for reducing the abundances of antibiotics, ARGs, and HPB in order to ensure the safety of vegetables and protect human health. | 2017 | 28284554 |