Antibiotic resistance genes and bacterial communities in cornfield and pasture soils receiving swine and dairy manures. - Related Documents




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700901.0000Antibiotic resistance genes and bacterial communities in cornfield and pasture soils receiving swine and dairy manures. Land application of animal manure could change the profiles of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs) and bacterial communities in receiving soils. Using high-throughput real-time quantitative PCR and 16S rRNA amplicon sequencing techniques, this study investigated the ARGs and bacterial communities in field soils under various crop (corn and pasture) and manure (swine and dairy) managements, which were compared with those of two non-manured reference soils from adjacent golf course and grassland. In total 89 unique ARG subtypes were found in the soil samples and they conferred resistance via efflux pump, cellular protection and antibiotic deactivation. Compared to the ARGs in the golf course and grassland soils (28 and 34 subtypes respectively), manured soils generally had greater ARG diversity (36-55 subtypes). Cornfield soil frequently receiving raw swine manure had the greatest ARG abundance. The short-term (one week) application of composted and liquid swine manures increased the diversity and total abundance of ARGs in cornfield soils. Intriguingly the composted swine manure only marginally increased the total abundance of ARGs, but substantially increased the number of ARG subtypes in the cornfield soils. The network analysis revealed three major network modules in the co-occurrence patterns of ARG subtypes, and the hubs of these major modules (intl1-1, vanC, and pncA) may be candidates for selecting indicator genes for surveillance of ARGs in manured soils. The network analyses between ARGs and bacteria taxa revealed the potential host bacteria for the detected ARGs (e.g., aminoglycoside resistance gene aacC4 may be mainly carried by Acidobacteriaceae). Overall, this study highlighted the potentially varying impact of various manure management on antibiotic resistome and microbiome in cornfield and pasture soils.201930861417
700210.9998Response of soil antibiotic resistance genes and bacterial communities to fresh cattle manure and organic fertilizer application. Livestock manure use in agriculture contributes to pollutants like antibiotic resistance genes (ARGs) and resistant bacteria. This practice could potentially facilitate ARGs development in soil ecosystems. Our study aimed to explore ARGs and bacterial communities in cattle manure from Ningxia beef cattle farms with varying breeding periods. We also assessed the impact of different application rates of cattle manure compost, created by mixing manure with different growing periods, on soil's physicochemical and heavy metal properties. High-throughput PCR and sequencing were used to analyze ARGs and bacterial communities. We aimed to understand ARGs dynamics in cattle manure during breeding stages and the impact of different fertilizer application rates on soil bacteria and resistance genes. We found 212 ARGs from cattle manure, spanning tetracycline, aminoglycoside, multidrug, and MLSB categories. Relative ARGs abundance was presented across breeding stages: lactation (C1), breeding (C3), pre-fattening (C4), calving (C2), and late fattening (C5). pH, total nitrogen (TN), electrical conductivity (EC), arsenic (As) and cadmium (Cd) presence significantly impacted ARGs quantity and microbial community structure in manure. Mobile genetic elements (MGEs) were the primary factor altering ARGs in manure (65.56%). Heavy metals contributed to 18.60% of ARGs changes. Manure application changed soil ARGs abundance, notably in soils with high application rates, primarily associated with aminoglycoside, multidrug and sulfonamide resistance. Soils with higher manure rates had elevated MGEs, positively correlated with most ARGs, suggesting MGEs' role in ARGs dissemination. Soil microbial community structure was influenced by fertilization, particularly with the highest application rate. Heavy metals (specifically Cd, contributing to 23.12%), microbial community changes (17.42%), and MGEs (17.38%) were the main factors affecting soil antibiotic resistance. Our study establishes a framework for understanding ARGs emergence in manure and treated soils. This informs strategies to mitigate environmental ARGs transmission and guides diverse livestock manure application and management.202339492397
725420.9998Field-based evidence for enrichment of antibiotic resistance genes and mobile genetic elements in manure-amended vegetable soils. The increasing prevalence of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) in the soil environment represents a serious threat to public health. In this study, the diversity and abundance of ARGs and mobile genetic elements (MGEs) in different years of manure-amended vegetable soils were investigated. A total of eight genes, including four tetracycline resistance genes: tetW, tetM, tetO and tetT; two sulfonamide resistance genes: sul1 and sul2; and two MGEs: intI1 and intI2; were quantified in ten vegetable soils. The relative abundance of ARGs in soils amended with manure was significantly higher than that in soils without manure application. The relative abundance of the intI1 and intI2 genes had significantly positive correlations with the relative abundance of the tetW, tetO, sul1 and sul2 genes. Under different concentrations of antibiotics, the resistant bacteria rates of manure-amended soil were much higher than the control soil. Bacillus and Chryseobacterium, more likely to be multi-drug-resistant bacteria, were detected in both two antibiotics. Moreover, the significant correlation was found between the concentrations of Cu and Zn and the ARGs. Our findings provide empirical evidence that the dissemination risk of ARGs and ARB in long-term manure-amended vegetable soils, which might promote to the development of effective strategies to reduce the spread of ARGs in agro-ecosystems.201930453260
725630.9998Impact of direct application of biogas slurry and residue in fields: In situ analysis of antibiotic resistance genes from pig manure to fields. Biogas slurry and residue contaminated with antibiotics are widely used as fertilizers in vegetable crop planting. However, their impact on the spreading of antibiotic resistance genes (ARGs) in vegetable fields is still largely unknown. In the present study, antibiotic resistant bacteria (ARB), ARGs and bacterial communities from pig manure to fields were monitored by using viable plate counts, high-throughput fluorescent quantitative PCR (HT-qPCR) and Illumina MiSeq sequencing. Eighty-three ARGs and 3 transposons genes were detected. Anaerobic digestion reduced relative abundance of tetracycline and Macrolide-Lincosamide-Streptogramin (MLSB) resistance genes. However, the number of ARB and the relative abundance of sulfa, aminoglycoside and florfenicol, chloramphenicol, and amphenicol (FCA) resistance genes, respectively, enriched up to 270 times and 52 times in biogas residue. Long-term application of biogas slurry and residue contaminated with antibiotics in fields increased the rate of ARB as well as relative abundance of ARGs and transposons genes. Additionally, bacterial communities significantly differed between the soil treated with biogas slurry and residue and the control sample, especially the phyla Bacteroidetes and Actinobacteria. Based on network analysis, 19 genera were identified as possible hosts of the detected ARGs. Our results provide an important significance for reasonable application of biogas slurry and residue.201829096257
725940.9998Practical survey on antibiotic-resistant bacterial communities in livestock manure and manure-amended soil. Through livestock manure fertilization, antibiotics, antibiotic-resistant bacteria and genes are transferred to agricultural soils, resulting in a high prevalence of antibiotic-resistant bacteria in the soil. It is not clear, however, whether a correlation exists between resistant bacterial populations in manure and manure-amended soil. In this work, we demonstrate that the prevalence of cephalexin-, amoxicillin-, kanamycin- and gentamicin-resistant bacteria as well as bacteria simultaneously resistant to all four antibiotics was much higher in manure-amended soils than in manure-free soil. 454-pyrosequencing indicated that the ARB and multiple antibiotic-resistant bacteria (MARB) in swine or chicken manure and manure-amended soil were mainly distributed among Sphingobacterium, Myroides, Enterococcus, Comamonas and unclassified Flavobacteriaceae. The genus Sphingobacterium was highly prevalent among ARB from swine manure and manure-amended soil, and was also the most dominant genus among MARB from chicken manure and manure-amended soil. Other dominant genera among ARB or MARB populations in manure samples, including Myroides, Enterococcus and Comamonas, could not be detected or were detected at very low relative abundance in manure-amended soil. The present study suggests the possibility of transfer of ARBs from livestock manures to soils and persistence of ARB in these environments.201626513264
685450.9998Characteristics and driving factors of antibiotic resistance genes in aquaculture products from freshwater ponds in China Yangtze River Delta. Antibiotic resistance genes (ARGs) are widespread in aquaculture and pose a huge threat to aquaculture organisms and human health. In this study, occurrences and relative abundances of ARGs were analysed in the guts of products cultured in freshwater ponds in the Yangtze River Delta region in China. A total of 29 ARGs were found in the gut samples, with detection frequencies ranging from 4.8% to 81%, and the relative abundances (ARGs/16S rRNA) ranging from 10(-7) to 1. In addition, the human dietary intake of ARGs via aquaculture products was assessed, where the daily intake of most ARGs via aquaculture products was higher than those via PM2.5 and drinking water, but lower than that via vegetables. The relative abundances of MGE (IS613, Tp614, tnpA and int1) were significantly correlated with those of multiple ARGs, indicating the horizontal gene transfer (HGT) of ARGs among gut microorganisms. Proteobacteria, Firmicutes and Actinobacteria were the dominated microbial communities found in the guts of aquaculture products. In addition, significant correlations were found between Cyanobacteria and int1, between Nitrospira and tetE, and between sul2 and aadA2, indicating potential same hosts of these genes. In addition, results from co-correlation indicated both HGT (dominated by MGEs) of ARGs and the enrichment of ARGs in bacteria. MGEs, mostly int1, were more effective than bacteria in increasing the ARG abundance. This study could provide a better understanding of the transmission of ARGs in the aquaculture environment and improve the quality of aquaculture products and the ecology.202436756971
695760.9997Untreated swine wastes changed antibiotic resistance and microbial community in the soils and impacted abundances of antibiotic resistance genes in the vegetables. Animal waste fertilization is a traditional agricultural practice, which may have adverse effects to soil ecosystem. However, the side-effects of animal waste fertilization on vegetables are less studied. Here we selected a swine farming village for investigation with a nearby village without swine farming as comparison. In the swine farming village, the farmers use untreated swine manure and wastewater as fertilizers for vegetable cultivation. In the reference village, the farmers mainly use commercial organic fertilizers. The objective of this study is to assess the impacts of untreated swine waste fertilization on both soils and vegetables in terms of antibiotics, antibiotic resistance genes (ARGs) and bacterial microbial communities. The results indicate that untreated swine waste fertilization caused both antibiotic and ARG contaminations and changed the microbial community compositions in the soils. Varieties of tetracyclines and related resistance genes were detected especially in swine wastewater treated soils. The soil quality was impacted with the relations to bacterial abundances and microbial geochemical functions. Proteobacteria and Bacteroidetes were prevalent and positively correlated to ARGs in soils, indicating they were potential antibiotic resistant bacteria. Antibiotics and ARGs were detected in vegetables of both villages. The abundances of ARGs were relatively higher in some vegetable samples of the swine farming village than the reference village. In addition, intracellular parasites Rickettsiales with positive correlation to ARGs were prevalent in some vegetables of swine farming village, indicating potential health risks through eating contaminated vegetables. The results of this study suggest that untreated swine wastes may cause adverse effects to not only agricultural soils but also associated vegetables.202032615438
684770.9997Nutrients, heavy metals and microbial communities co-driven distribution of antibiotic resistance genes in adjacent environment of mariculture. With the rapid development of aquaculture, the large amounts of pollutants were discharged into the aquatic environment, where the detected antibiotic resistance genes (ARGs) have drawn increasing attention due to their potential threats to ecological environment and human health. Thus, the impact of mariculture on ARGs was assessed and the underlying mechanism of their propagation was explained. Sediments from eight sampling sites were collected along a mariculture drainage ditch, and the sediment in Yellow River Delta National Park was used as a non-mariculture control. Microbial ARGs qPCR array and illumina sequencing of 16S rRNA gene were applied to examine the changing patterns of ARGs and bacterial communities. Results showed that 18 ARGs (3 fluoroquinolone, 1 aminoglycoside, 3 macrolide-lincosamide-streptogramin B, 2 tetracycline, and 9 beta-lactam resistance genes) were influenced by mariculture, and ARGs abundance and diversity were significantly increased in mariculture sediments (p < 0.05). A remarkable shift in bacterial community structure and composition was also observed. The abundance of most of ARGs were significantly decreased in the estuary samples, implying that seawater had a significant dilution effect on the ARGs emission from the mariculture sites. Partial redundancy analysis showed that nutrients, heavy metals, and bacteria communities might directly and indirectly contribute to ARGs propagation, suggesting that the profile and dissemination of ARGs were driven by the combined effects of multiple factors in mariculture-impacted sites.201727814984
694980.9997Tracing 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
725590.9997Distribution of quinolone and macrolide resistance genes and their co-occurrence with heavy metal resistance genes in vegetable soils with long-term application of manure. The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.202234559332
6846100.9997Antibiotic resistance genes in an urban river as impacted by bacterial community and physicochemical parameters. Antibiotic resistance genes (ARGs) in urban rivers are a serious public health concern in regions with poorly planned, rapid development. To gain insights into the predominant factors affecting the fate of ARGs in a highly polluted urban river in eastern China, a total of 285 ARGs, microbial communities, and 20 physicochemical parameters were analyzed for 17 sites. A total of 258 unique ARGs were detected using high-throughput qPCR, and the absolute abundance of total ARGs was positively correlated with total organic carbon and total dissolved nitrogen concentrations (P < 0.01). ARG abundance and diversity were greatly altered by microbial community structure. Variation partitioning analysis showed that the combined effects of multiple factors contributed to the profile and dissemination of ARGs, and variation of microbial communities was the major factor affecting the distribution of ARGs. The disparate distribution of some bacteria, including Bacteroides from mammalian gastrointestinal flora, Burkholderia from zoonotic infectious diseases, and Zoogloea from wastewater treatment, indicates that the urban river was strongly influenced by point-source pollution. Results imply that microbial community shifts caused by changes in water quality may lead to the spread of ARGs, and point-source pollution in urban rivers requires greater attention to control the transfer of ARGs between environmental bacteria and pathogens.201728864929
7257110.9997Housefly 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
7412120.9997Effect of composting and storage on the microbiome and resistome of cattle manure from a commercial dairy farm in Poland. Manure from food-producing animals, rich in antibiotic-resistant bacteria and antibiotic resistance genes (ARGs), poses significant environmental and healthcare risks. Despite global efforts, most manure is not adequately processed before use on fields, escalating the spread of antimicrobial resistance. This study examined how different cattle manure treatments, including composting and storage, affect its microbiome and resistome. The changes occurring in the microbiome and resistome of the treated manure samples were compared with those of raw samples by high-throughput qPCR for ARGs tracking and sequencing of the V3-V4 variable region of the 16S rRNA gene to indicate bacterial community composition. We identified 203 ARGs and mobile genetic elements (MGEs) in raw manure. Post-treatment reduced these to 76 in composted and 51 in stored samples. Notably, beta-lactam, cross-resistance to macrolides, lincosamides and streptogramin B (MLSB), and vancomycin resistance genes decreased, while genes linked to MGEs, integrons, and sulfonamide resistance increased after composting. Overall, total resistance gene abundance significantly dropped with both treatments. During composting, the relative abundance of genes was lower midway than at the end. Moreover, higher biodiversity was observed in samples after composting than storage. Our current research shows that both composting and storage effectively reduce ARGs in cattle manure. However, it is challenging to determine which method is superior, as different groups of resistance genes react differently to each treatment, even though a notable overall reduction in ARGs is observed.202438616224
6856130.9997Effects of the coexistence of antibiotics and heavy metals on the fate of antibiotic resistance genes in chicken manure and surrounding soils. Both heavy metals and antibiotics exert selection pressure on bacterial resistance, and as they are commonly co-contaminated in the environment, they may play a larger role in bacterial resistance. This study examined how breeding cycles affect antibiotic resistance genes (ARGs) in chicken manure and the surrounding topsoils at 20, 50, 100, 200, and 300 m from twelve typical laying hen farms in the Ningxia Hui Autonomous Region of northwest China. Six antibiotics, seven heavy metals, ten mobile genetic elements (MGEs), and microbial community affected the ARGs profile in chicken dung and soil samples. Tetracycline antibiotic residues were prevalent in chicken manure, as were relatively high content of aureomycin during each culture period. Zinc (Zn) content was highest among the seven heavy metals in chicken feces. Chicken dung also enriched aminoglycosides, MLSB, and tetracycline ARGs, notably during brooding and high production. The farm had a minimal influence on antibiotics in the surrounding soil, but its effect on ARGs and MGEs closer to the farm (50 m) was stronger, and several ARGs and MGEs increased with distance. Manure microbial composition differed dramatically throughout breeding cycles and sampling distances. ARGs were more strongly related with antibiotics and heavy metals in manure than soil, whereas MGEs were the reverse. Antibiotics, heavy metals, MGEs, and bacteria in manure accounted 12.28%, 22.25%, 0.74%, and 0.19% of ARGs composition variance, respectively, according to RDA and VPA. Bacteria (2.89%) and MGEs (2.82%) only affected soil ARGs composition. These findings showed that heavy metals and antibiotics are the main factors affecting faecal ARGs and bacteria and MGEs soil ARGs. This paper includes antibiotic resistance data for large-scale laying hen husbandry in northwest China and a theoretical framework for decreasing antibiotic resistance.202337586197
6838140.9997Seasonal variation characteristics of inhalable bacteria in bioaerosols and antibiotic resistance genes in Harbin. Bioaerosols have received extensive attention due to their impact on climate, ecological environment, and human health. This study aimed to reveal the driving factors that structure bacterial community composition and the transmission route of antibiotic resistance genes (ARGs) in PM(2.5). The results showed that the bacterial concentration in spring (8.76 × 10(5) copies/m(3)) was significantly higher than that in summer (1.03 × 10(5) copies/m(3)) and winter (4.74 × 10(4) copies/m(3)). Low temperatures and air pollution in winter negatively affected bacterial concentrations. Keystone taxa were identified by network analysis. Although about 50 % of the keystone taxa had low relative abundances, the strong impact of complex interactions between keystone taxa and other taxa on bacterial community structure deserved attention. The bacterial community assembly was dominated by stochastic processes (79.3 %). Interactions between bacteria and environmental filtering together affected bacterial community composition. Vertical gene transfer played an important role in the transmission of airborne ARGs. Given the potential integration and expression of ARGs in recipients, the human exposure risk due to high concentrations of ARGs and mobile genetic elements cannot be ignored. This study highlights human exposure to inhalable bacterial pathogens and ARGs in urban areas.202336584645
6864150.9997Metagenomics analysis revealing the occurrence of antibiotic resistome in salt lakes. Although antimicrobial resistance genes (ARGs) in dozens of environments have been well documented, the distribution of ARGs in salt lake ecosystems has been less intensively investigated. In this study, the broad-spectrum ARG profiles, microbial community composition and the comprehensive associations between microbiome and antimicrobial resistome in four salt lakes were investigated using a metagenomic approach. A total of 175 ARG subtypes affiliated with 19 ARG types were detected, and ARGs conferring resistance to multidrug, bacitracin, and macrolide-lincosamide-streptogramin (MLS) accounted for 71.2% of the total ARG abundance. However, the abundance of ARGs significantly decreased with the increasing salinity in the lakes. Both ARG profiles and microbial community structure presented remarkable discrepancies in different lakes, as well as in different sample types. Microbes such as genera Azoarcus, Aeromonas, Pseudomonas, and Kocuria, significantly co-occurred with multiple ARGs, indicating that these bacteria are potential ARG hosts in salt lake ecosystems. Collectively, this work provides new insights into the occurrence and distribution of ARGs in salt lake ecosystems.202134380279
7010160.9997Dynamics of metal(loid) resistance genes driven by succession of bacterial community during manure composting. Metal(loid) resistance genes (MRGs) play important roles in conferring resistance to metal(loid)s in bacterial communities. How MRGs respond to bacterial succession during manure composting remains largely unknown. Metagenomics was used in the present study to investigate the compositional changes of MRGs, their candidate hosts and association with integrons during thermophilic composting of chicken manures. MRGs conferring resistance to 20 metal(loid)s were detected, and their diversity and abundance (normalized to the abundance of 16S rRNA genes) were significantly reduced during composting. MRGs associated with integron were exclusively observed in proteobacterial species. Class 1 integron likely played an important role in maintaining mercury-resistance mer operon genes in composts. Escherichia coli harbored the most abundant MRGs in the original composting material, whereas species of Actinobacteria and Bacilli became more important in carrying MRGs during the late phases. There were significant linear relationships between the relative abundance of some specific bacterial species (E. coli, Actinobacteria species and Enterococcus faecium) and the abundance of MRGs they potentially harbored. The succession of these bacteria contributed to an overall linear regression between the relative abundance of all predicted candidate hosts and the abundance of total MRGs. Our results suggest that the succession of bacterial community was the main driver of MRG dynamics during thermophilic composting.201931563779
7141170.9997The fate of antibiotic resistance genes and their association with bacterial and archaeal communities during advanced treatment of pig farm wastewater. Advanced wastewater treatment plants are widely used in most large-scale pig farms in southern China. However, the fate of antibiotic resistance genes (ARGs) and their association with bacterial and archaeal communities during advanced wastewater treatment remain unclear. In this study, the profiles of ARGs in typical advanced wastewater treatment plants were surveyed using metagenomic analysis. The results showed that 279- 326 different subtypes of ARGs were detected in raw wastewater, with a total abundance of 5.98 ± 0.48 copies per bacterial cell. During the advanced wastewater treatment, the abundance and number of ARGs were significantly reduced. Microbial communities (bacteria and archaea) contributed the most to the variation in ARG abundance and composition (PCA axis_1), accounting for 10.8 % and 15.7 %, respectively, followed by mobile genetic elements (MGEs) and physicochemical factors. Special attention should be given to potential pathogenic bacteria such as Escherichia, Streptococcus, Enterococcus and Staphylococcus and archaea such as Methanocorpusculum, Candidatus Methanoplasma and Candidatus Methanomethylophilus, which were important potential ARG hosts. Bacterial communities may indirectly affect ARG variation by affecting archaeal communities. These findings indicated that ARG levels in pig farm wastewater can be effectively reduced during advanced treatment and highlighted the important role played by archaea, which should not be ignored.202236041618
7065180.9997Exploring the immediate and long-term impact on bacterial communities in soil amended with animal and urban organic waste fertilizers using pyrosequencing and screening for horizontal transfer of antibiotic resistance. We investigated immediate and long-term effects on bacterial populations of soil amended with cattle manure, sewage sludge or municipal solid waste compost in an ongoing agricultural field trial. Soils were sampled in weeks 0, 3, 9 and 29 after fertilizer application. Pseudomonas isolates were enumerated, and the impact on soil bacterial community structure was investigated using 16S rRNA amplicon pyrosequencing. Bacterial community structure at phylum level remained mostly unaffected. Actinobacteria, Proteobacteria and Chloroflexi were the most prevalent phyla significantly responding to sampling time. Seasonal changes seemed to prevail with decreasing bacterial richness in week 9 followed by a significant increase in week 29 (springtime). The Pseudomonas population richness seemed temporarily affected by fertilizer treatments, especially in sludge- and compost-amended soils. To explain these changes, prevalence of antibiotic- and mercury-resistant pseudomonads was investigated. Fertilizer amendment had a transient impact on the resistance profile of the soil community; abundance of resistant isolates decreased with time after fertilizer application, but persistent strains appeared multiresistant, also in unfertilized soil. Finally, the ability of a P. putida strain to take up resistance genes from indigenous soil bacteria by horizontal gene transfer was present only in week 0, indicating a temporary increase in prevalence of transferable antibiotic resistance genes.201425087596
7216190.9997Tracking antibiotic resistance through the environment near a biosolid spreading ground: Resistome changes, distribution, and metal(loid) co-selection. The application of urban wastewater treatment plants (WWTPs) products to agricultural lands has contributed to the rising level of antibiotic resistance and drawn a critical public health concern. It has not been thoroughly investigated at which spatial scales a biosolid applied area as a potentially predominant source affects surrounding soil resistomes. This study investigated distribution and impact of WWTP biosolids treated with anaerobic digestion on an agricultural area. Heterotrophic plate counts (HPCs) and quantitative polymerase chain reaction (qPCR) were performed for detection of selected antibiotic-resistant bacteria (ARB), selected antibiotic resistance genes (ARGs), intI1 genes, and 16S rRNA genes. Biosolid samples contained significantly higher levels of selected ARGs than the raw agricultural soils (p < 0.05). The average relative abundances of intI1, sul1, bla(SHV), and ermB genes were significantly higher in biosolid-amended soils than nearby agricultural soils (p < 0.05). Spatial interpolation analysis of relative gene abundances of intI1, sul1, sul2, and tetW across the studied area further indicated directional trends towards the northwest and southeast directions, highlighting possible airborne spread. Concentrations of Co, Cu, Ni, and Fe were found to be significantly and positively correlated with relative abundances of intI1, sul1, and tetW genes (p < 0.05). The resistance ratios of culturable antibiotic-resistant bacteria in agricultural soils with biosolid amendments were generally identical to those without biosolid amendments. This study will advance the understanding of the antibiotic resistome in agricultural soils impacted by long-term waste reuse and inform the evaluation strategies for future biosolids application and management.202235121038