The abundance and diversity of antibiotic resistance genes in layer chicken ceca is associated with farm enviroment. - Related Documents




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311101.0000The abundance and diversity of antibiotic resistance genes in layer chicken ceca is associated with farm enviroment. Industrialized layer chicken feedlots harbor complex environmental microbial communities that affect the enrichment and exchange of gut bacteria and antibiotic resistance genes (ARGs). However, the contribution of different environmental sources to the gut ARGs of layer chickens is not clear. Here, layer chicken gut and environmental samples (air, water, feed, cage, feather, maternal hen feces, uropygial glands) were collected during the early 3 month period before the laying of eggs, and the source and characteristics of the gut microorganisms and ARGs were analyzed by performing 16S rRNA and metagenomic sequencing. The results showed that the abundances of Bacteroidetes and Actinobacteria in cecum of layer chickens gradually increased, while that of Proteobacteria decreased with age, and the number and relative abundance of ARGs decreased significantly with age. On day 5, 57% of the layer chicken cecal ARGs were from feather samples, and 30% were from cage samples. Subsequently, the contribution of cage ARGs became progressively more prominent over time. At days 30 and 57, the contribution of cage ARGs to the chick cecal ARGs reached 63.3 and 69.5%, respectively. The bacterial community composition (especially the abundances of Klebsiella pneumoniae and Escherichia coli) was the major factor impacting the ARG profile. K. pneumoniae and E. coli were mainly transmitted from feathers to the layer chicken cecum, and the contribution rates were 32 and 3.4%, respectively. In addition, we observed the transmission of ARG-carrying bacteria (Bacteroides fragilis) from the cage to the gut, with a contribution rate of 11.5%. It is noteworthy that B. fragilis is an opportunistic pathogen that may cause diarrhea in laying hens. These results can provide reference data for the healthy breeding of layer chickens and the prevention and control of ARG pollution.202337455745
321610.9998Effects of different laying periods on airborne bacterial diversity and antibiotic resistance genes in layer hen houses. Poultry farms are a complex environment for close contact between humans and animals. Accumulating evidence has indicated that pathogens and drug resistance genes in chicken houses may pose a serious threat to public health and economic concerns. However, insufficient knowledge of the indoor aerosol microbiome and resistome profiles of layer hen houses hampers the understanding of their health effects. Environmental surveillance of antibiotic resistance may contribute to a better understanding and management of the human exposure risk of bioaerosols under the environmental conditions of chicken houses. In addition, the chicken house has a long operation cycle, and the bacterial diversity and antibiotic resistance genes of aerosols in different periods may be different. In this study, air samples were collected from 18 chicken houses on three farms, including the early laying period (EL), peak laying period (PL), and late laying period (LL). 16S rRNA gene sequencing and metagenomics were used to study the composition of the bacteria and resistome in aerosols of layer hen houses and the results showed that they varied with laying period. The highest alpha diversity of bacteria was observed in PL bioaerosols. The dominant bacterial phyla included Firmicutes, Bacteroidetes and Proteobacteria. Three potential pathogenic bacterial genera (Bacteroides, Corynebacterium and Fusobacterium) were found. The most abundant ARG type was aminoglycosides in all laying periods. In total, 22 possible ARG host genera were detected. ARG subtypes and abundance were both higher in LL. Network analysis also showed higher co-occurrence patterns between the bacteria and resistome in bioaerosols. The laying period plays an important role in the bacterial community and resistome in layer house aerosols.202337119673
311020.9998Microbial community, pathogenic bacteria and high-risk anti-biotic resistance genes at two tropical coastal beaches adjacent to villages in Hainan, China. OBJECTIVE: The aim of the study was to explore the correlation between characteristics of microbial community, pathogenic bacteria and high-risk antibiotic-resistant genes, between coastal beaches and a multi-warm-blooded host, as well as to determine potential species biomarkers for faecal source contamination on tropical coastal beaches in China. MATERIAL AND METHODS: The 'One-Health' approach was used in a microbiological study of beaches and warm-blooded hosts. The microbial.community was analyzed using 16S rRNA gene amplicons and shotgun metagenomics on Illumina NovaSeq. RESULTS: The Chao, Simpson, Shannon, and ACE indices of non-salt beach were greater than those of salt beaches at the genus and OTU levels (P < 0.001). Bacteroidota, Halanaerobiaeota, Cyanobacteria, and Firmicutes were abundant on salt beaches (P<0.01). Human-sourced microorganisms were more abundant on salt beaches, which accounted for 0.57%. Faecalibacterium prausnitzii and Eubacterium hallii were considered as reliable indicators for the contamination of human faeces. High-risk carbapenem-resistant Klebsiella pneumoniae and the genotypes KPC-14 and KPC-24 were observed on salt beaches. Tet(X3)/tet(X4) genes and four types of MCR genes co-occurred on beaches and humans; MCR9.1 accounted for the majority. Tet(X4) found among Cyanobacteria. Although rarely reported at Chinese beaches, pathogens, such as Vibrio vulnificus, Legionella pneumophila, and Helicobacter pylori, were observed. CONCLUSIONS: The low microbial community diversity, however, did not indicate a reduced risk. The transfer of high-risk ARGs to extreme coastal environments should be given sufficient attention.202338153067
321730.9998Distribution and environmental dissemination of antibiotic resistance genes in poultry farms and surrounding ecosystems. Antibiotic resistance poses a significant threat to human and animal health worldwide, with farms serving as crucial reservoirs of Antibiotic Resistance Genes (ARGs) and Antibiotic-resistant bacteria. However, the distribution of ARGs in poultry farms and their transmission patterns in the environment remain poorly understood. This study collected samples of aerosol microorganisms, cloacal matter, soil, and vegetables from poultry farms and surrounding environments at three different distances. We used 16S rRNA gene sequencing and HT-qPCR to analyze the characteristics of aerosol microbial communities and the abundance of ARGs. At the phylum level, Proteobacteria, Firmicutes, and Bacteroidetes were dominant in cloacal samples, aerosol samples, and vegetable samples, while Proteobacteria Actinobacteriota and Acidobacteria dominated soil. Pseudomonas was dominant in cloacal samples at the genus level, whereas Fusobacterium was prevalent in soil. The diversity and richness of bacterial communities were more similar between cloacal samples than those observed between either sample type compared with soil. Our results showed that tetracycline and aminoglycoside ARG relative abundance was high across all sample types but significantly increased within feces/air compared to soils/vegetables. Association analysis revealed five potential host genera for ARG/MGE presence among various microbiota populations studied here. Our findings confirm that farms are important sources for the environmental dissemination of pathogens and ARGs.202539689477
321240.9998Distribution and driving factors of antibiotic resistance genes in treated wastewater from different types of livestock farms. Treated wastewater from livestock farms is an important reservoir for antibiotic resistance genes (ARGs), and is a main source of ARGs in the environment. However, the distribution and driving factors of ARGs in treated wastewater from different types of livestock farms are rarely reported. In this study, treated wastewater from 69 large-scale livestock farms of different types, including broiler, layer, and pig farms, was collected, and 11 subtypes of ARGs, 2 mobile genetic elements (MGEs) and bacterial community structure were analyzed. The results revealed detection rates of NDM-1 and mcr-1 of 90 % and 43 %, respectively, and the detection rates of other ARGs were 100 %. The relative abundance of ARGs, such as tetA, tetX and strB, in broiler farms was significantly higher than that in layer farms, but the bacterial α diversity was significantly lower than that in other farm types. Furthermore, although the treatment process had a greater impact on the physicochemical properties of the treated wastewater than the livestock type, livestock type was the main factor affecting the bacterial community in the treated wastewater. The analysis of potential host bacteria of ARGs revealed significant differences in the host bacteria of ARGs in treated wastewater from different types of livestock farms. The host bacteria of ARGs in broiler farms mainly belonged to Actinobacteria, layer farms mainly belonged to Proteobacteria, and pig farms mainly belonged to Firmicutes. Additionally, redundancy analysis showed that the distribution of ARGs may have resulted from the combination of multiple driving factors in different types of livestock farms, among which tnpA and NH(4)(+)-N were the main influencing factors. This study revealed multiple driving factors for the distribution of typical ARGs in treated wastewater from different types of livestock farms, providing basic data for the prevention and control of ARG pollution in agricultural environments.202235934031
350950.9998Persistence and spatial variation of antibiotic resistance genes and bacterial populations change in reared shrimp in South China. More attention has been paid to the abundance and diversity of antibiotic resistance genes (ARGs) in aquatic environments. However, few studies have investigated the persistence and spatial variation of ARGs in aquatic organisms. This study investigated the occurrence and abundance of ARGs and the bacterial populations in shrimp intestinal tracts during the rearing period in different regions of Guangdong, South China. The results showed that sul1, sul2, qnrD, and floR were the predominant ARGs. Compared with those of juvenile shrimp, the total concentrations of ARGs in the intestinal tract of adult shrimp in three shrimp farms were 2.45-3.92 times higher (p < 0.05), and the bacterial populations in the adult shrimp intestinal tract changed considerably. Redundancy analysis (RDA) showed that the abundance of Proteobacteria, Firmicutes, and Verrucomicrobia in Farms A, B, and C, respectively, were strongly positively correlated with the most abundant and predominant genes (sul1 and qnrD for Farm A; floR and sul2 for Farm B; floR and sul2 for Farm C) in the shrimp intestinal tract. The results of this study indicated that ARGs gained persistence in the developmental stages of the reared shrimp. Different phyla of predominant bacteria were responsible for the increase of ARGs abundance in the shrimp intestinal tract in different regions. This study represents a case study of the persistence and spatial variation of ARGs in aquaculture and can be a reference for the determination of harmful impacts of ARGs on food safety and human health.201829990953
321460.9997Characteristics of the antibiotic resistance genes in the soil of medical waste disposal sites. The inappropriate disposal of medical waste allows bacteria to acquire antibiotic resistance, which results in a threat to public health. Antibiotic resistance gene (ARG) profiles were determined for 45 different soil samples containing medical waste and 15 nearby soil samples as controls. Besides physical and chemical analyses (i.e., dry matter content, pH value, and metal content), the genomes of microorganisms from the soil samples were extracted for high-throughput sequencing. ARG abundances of these samples were obtained by searching the metagenomic sequences against the antibiotic resistance gene database and the copies of ARGs per copy of the 16S rRNA gene at different levels were assessed. The results showed medical waste accumulation significantly enriched the contents of Cu, Cr, Pb, and As in the tested soil samples. Compared to the controls, the samples collected from areas containing medical waste were significantly enriched (p < 0.05, t-test) with ARGs annotated as sulfonamide and multidrug resistance genes, and in particular, the subtypes sul1 and sul2 (sulfonamide resistance genes), and multidrug_transporter (multidrug resistance gene). Moreover, the ARGs of the samples from the polluted areas were more diverse than those of the control samples (p < 0.05, t-test). The comparatively higher abundance and diversity of ARGs in contaminated soil pose a potential risk to human health.202032402966
350870.9997Prevalence and distribution of antibiotic resistance in marine fish farming areas in Hainan, China. Antibiotic resistance represents a global health crisis for humans, animals, and for the environment. Transmission of antibiotic resistance through environmental pathways is a cause of concern. In this study, quantitative PCR and culture-dependent bacteriological methods were used to detect the abundance of antibiotic resistance genes (ARGs) and the quantity of culturable heterotrophic antibiotic-resistant bacteria (ARB) in marine fish farming areas. The results indicated that sul and tet family genes were widely distributed in marine fish farming areas of Hainan during both rearing and harvesting periods. Specifically, sul1 and tetB were the most dominant ARGs. The total abundance of ARGs increased significantly from the rearing to the harvesting period. A total of 715 ARB strains were classified into 24 genera, within these genera Vibrio, Acinetobacter, Pseudoalteromonas, and Alteromonas are opportunistic pathogens. High bacterial resistance rate to oxytetracycline (OT) was observed. The numbers of OT- and enrofloxacin-resistant bacteria dropped significantly from rearing the period to the harvesting. The co-occurrence pattern showed that Ruegeria and tetB could be indicators of ARB and ARGs, respectively, which were found in the same module. Redundancy analysis indicated that salinity was positively correlated with the most dominant ARB, and was negatively correlated with the most dominant ARGs. These findings demonstrated the prevalence and persistence of ARGs and ARB in marine fish farming areas in China.201930414589
320880.9997Effects of Antibiotic Residues on Fecal Microbiota Composition and Antimicrobial Resistance Gene Profiles in Cattle from Northwestern China. Grazing is a free-range farming model commonly practiced in low-external-input agricultural systems. The widespread use of veterinary antibiotics in livestock farming has led to significant environmental accumulation of antibiotic residues and antibiotic resistance genes (ARGs), posing global health risks. This study investigated the antibiotic residues, bacterial community, ARG profiles, and mobile genetic elements (MGEs) in cattle feces from three provinces in western China (Ningxia, Xinjiang, and Inner Mongolia) under grazing modes. The HPLC-MS detection showed that the concentration of tetracycline antibiotics was the highest in all three provinces. Correlation analysis revealed a significant negative correlation between antibiotic residues and the diversity and population abundance of intestinal microbiota. However, the abundance of ARGs was directly proportional to antibiotic residues. Then, the Sankey analysis revealed that the ARGs in the cattle fecal samples were concentrated in 15 human pathogenic bacteria (HPB) species, with 9 of these species harboring multiple drug resistance genes. Metagenomic sequencing revealed that carbapenemase-resistant genes (bla(KPC) and bla(VIM)) were also present in considerable abundance, accounting for about 10% of the total ARGs detected in three provinces. Notably, Klebsiella pneumoniae strains carrying bla(CTX-M-55) were detected, which had a possibility of IncFII plasmids harboring transposons and IS19, indicating the risk of horizontal transfer of ARGs. This study significantly advances the understanding of the impact of antibiotic residues on the fecal microbiota composition and ARG profiles in grazing cattle from northwestern China. Furthermore, it provides critical insights for the development of rational antibiotic usage strategies and comprehensive public health risk assessments.202540732167
534890.9997Characterization of microbial community and antibiotic resistome in intra urban water, Wenzhou China. The present study investigated the water quality index, microbial composition and antimicrobial resistance genes in urban water habitats. Combined chemicals testing, metagenomic analyses and qualitative PCR (qPCR) were conducted on 20 locations, including rivers from hospital surrounds (n = 7), community surrounds (n = 7), and natural wetlands (n = 6). Results showed that the indexes of total nitrogen, phosphorus, and ammonia nitrogen of hospital waters were 2-3 folds high than that of water from wetlands. Bioinformatics analysis revealed a total of 1,594 bacterial species from 479 genera from the three groups of water samples. The hospital-related samples had the greatest number of unique genera, followed by those from wetlands and communities. The hospital-related samples contained a large number of bacteria associated with the gut microbiome, including Alistipes, Prevotella, Klebsiella, Escherichia, Bacteroides, and Faecalibacterium, which were all significantly enriched compared to samples from the wetlands. Nevertheless, the wetland waters enriched bacteria from Nanopelagicus, Mycolicibacterium and Gemmatimonas, which are typically associated with aquatic environments. The presence of antimicrobial resistance genes (ARGs) that were associated with different species origins in each water sample was observed. The majority of ARGs from hospital-related samples were carried by bacteria from Acinetobacter, Aeromonas and various genera from Enterobacteriaceae, which each was associated with multiple ARGs. In contrast, the ARGs that were exclusively in samples from communities and wetlands were carried by species that encoded only 1 to 2 ARGs each and were not normally associated with human infections. The qPCR showed that water samples of hospital surrounds had higher concentrations of intI1 and antimicrobial resistance genes such as tetA, ermA, ermB, qnrB, sul1, sul2 and other beta-lactam genes. Further genes of functional metabolism reported that the enrichment of genes associated with the degradation/utilization of nitrate and organic phosphodiester were detected in water samples around hospitals and communities compared to those from wetlands. Finally, correlations between the water quality indicators and the number of ARGs were evaluated. The presence of total nitrogen, phosphorus, and ammonia nitrogen were significantly correlated with the presence of ermA and sul1. Furthermore, intI1 exhibited a significant correlation with ermB, sul1, and bla(SHV), indicating a prevalence of ARGs in urban water environments might be due to the integron intI1's diffusion-promoting effect. However, the high abundance of ARGs was limited to the waters around the hospital, and we did not observe the geographical transfer of ARGs along with the river flow. This may be related to water purifying capacity of natural riverine wetlands. Taken together, continued surveillance is required to assess the risk of bacterial horizontal transmission and its potential impact on public health in the current region.202337396356
5301100.9997High levels of antibiotic resistance genes and opportunistic pathogenic bacteria indicators in urban wild bird feces. This study analyzed fresh feces from three common bird species that live in urban environments and interact with human communities. Antibiotic resistance genes (ARGs) encoding resistance to three major classes of antibiotics (i.e., tetracyclines, β-lactams, and sulfonamides) and the mobile genetic element integrase gene (intI1) were abundant (up to 10(9), 10(8), 10(9), and 10(10) copies/g dry feces for tetW, bla(TEM), sul1, and intI1, respectively), with relative concentrations surprisingly comparable to that in poultry and livestock that are occasionally fed antibiotics. Biomarkers for opportunistic pathogens were also abundant (up to 10(7) copies/g dry feces) and the dominant isolates (i.e., Enterococcus spp. and Pseudomonas aeruginosa) harbored both ARGs and virulence genes. ARGs in bird feces followed first-order attenuation with half-lives ranging from 1.3 to 11.1 days in impacted soil. Although residual antibiotics were detected in the feces, no significant correlation was observed between fecal antibiotic concentrations and ARG relative abundance. Thus, other unaccounted factors likely contributed selective pressure for ARG maintenance. These findings highlight the contribution of wild urban bird feces to the maintenance and dissemination of ARGs, and the associated health risks.202032663725
3215110.9997Prevalence of antibiotic resistance genes its association with microbiota in raw milk of northwest Xinjiang. The issue of antibiotic resistance caused by antibiotic resistance genes (ARGs) has become a significant concern in environmental research in recent years, while raw milk is an important link in the food chain and has become one of the carriers and reservoirs of ARGs, which has not been taken seriously. This research employed high-throughput quantitative PCR and Illumina sequencing techniques targeting the 16S rRNA gene. These methods were used to examine the bacterial community composition and genes associated with antibiotic resistance in raw milk samples collected from the northwestern area of Xinjiang. An aggregate of 31 distinct resistance alleles were identified, with their abundance reaching as high as 3.70 × 10(5) copies per gram in the analyzed raw milk samples. Microorganisms harboring ARGs that confer resistance to beta-lactams, tetracyclines, aminoglycosides, and chloramphenicol derivatives were prevalent in raw milk. Procrustes analysis revealed a certain degree of correlation between the microbial community and the antibiotic resistance gene (ARG) profiles. Furthermore, network analysis demonstrated that Actinobacteria and Firmicutes were the predominant phyla exhibiting co-occurrence relationships with specific ARGs. Combining the findings from Variance Partitioning Analysis (VPA), the distribution of ARGs was mainly driven by three factors: the combined effect of physicochemical properties and mobile genetic elements (MGEs) (33.5%), the interplay between physicochemical parameters and microbial communities (31.8%), and the independent contribution of physicochemical factors (20.7%). The study demonstrates that the overall abundance of ARGs correlates with physicochemical parameters, bacterial community composition, and the presence of MGEs. Furthermore, understanding these associations facilitates the evaluation of antibiotic resistance risks, thereby contributing to enhanced farm management practices and the assurance of food safety.202540718809
3219120.9997Airborne bacterial contaminations in typical Chinese wet market with live poultry trade. Chinese wet markets with live poultry trade have been considered as major sources of pathogen dissemination, and sites for horizontal transfer of bacterial and viral pathogens. In this study, the pathogenic bacteria and antibiotic resistant genes (ARGs) in air samples collected at a typical Chinese wet market had been analysis and quantified. Corynebacterium minutissimum and other pathogenic bacteria accounted for 0.81-8.02% of the whole microbial community in different air samples. The four ARGs quantified in this study showed a comparable relative concentration (copies/ng_DNA) with municipal wastewater. Poultry manures were demonstrated to be important microbial contamination source in wet market, which was supported by both microbial composition based source tracking and the quantification of airborne microbial density. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination. Our results indicate bioaerosols acted as important route for the transmissions of pathogens and ARGs. Continued surveillance of airborne microbial contamination is required in poultry trade wet market. PRACTICAL IMPLICATIONS: Urban live poultry markets are important sources of pathogen dissemination, and sites for horizontal transfer of viral and bacterial pathogens. In the present field-study, pathogenic bacteria and antibiotic resistance genes were focused to provide quantitative information on the levels of microbial contaminations at the indoor air of wet markets. Results demonstrated that poultry manures were important microbial contamination source in wet market, and in the meanwhile bioaerosols were identified as important route for the transmissions of microbial contaminants. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination.201627503629
7112130.9997Occurrence of antibiotic resistance genes and microbial source tracking markers in the water of a karst spring in Germany. The emergence of antimicrobial resistances causes serious public health concerns worldwide. In recent years, the aquatic ecosystem has been recognized as a reservoir for antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). The prevalence of 11 ARGs, active against six antibiotic classes (β-lactams, aminoglycosides, tetracycline, macrolides, trimethoprim, and sulfonamides), was evaluated at a karst spring (Gallusquelle) in Germany, using molecular biological methods. In addition, fecal indicator bacteria (FIB), turbidity, electrical conductivity, spring discharge, and microbial source tracking markers specific for human, horse, chicken, and cow were determined. The ARGs most frequently detected were ermB (42.1%), tet(C) (40.8%), sul2 (39.5%), and sul1 (36.8%), which code for resistance to macrolides, tetracycline and sulfonamides, respectively. After a heavy rain event, the increase in FIB in the spring water was associated with the increase in ARGs and human-specific microbial source tracking (MST) markers. The determined correlations of the microbiological parameters, the observed overflow of a combined sewer overflow basin a few days before the increase of these parameters, and the findings of previous studies indicate that the overflow of this undersized basin located 9 km away from the spring could be a factor affecting the water quality of the karst spring. Our results provide a scientific basis for minimization of the input of fecal pollution and thus ARGs into the karst spring.202032629259
3205140.9997Determinants for antimicrobial resistance genes in farm dust on 333 poultry and pig farms in nine European countries. Livestock feces with antimicrobial resistant bacteria reaches the farm floor, manure pit, farm land and wider environment by run off and aerosolization. Little research has been done on the role of dust in the spread of antimicrobial resistance (AMR) in farms. Concentrations and potential determinants of antimicrobial resistance genes (ARGs) in farm dust are at present not known. Therefore in this study absolute ARG levels, representing the levels people and animals might be exposed to, and relative abundances of ARGs, representing the levels in the bacterial population, were quantified in airborne farm dust using qPCR. Four ARGs were determined in 947 freshly settled farm dust samples, captured with electrostatic dustfall collectors (EDCs), from 174 poultry (broiler) and 159 pig farms across nine European countries. By using linear mixed modeling, associations with fecal ARG levels, antimicrobial use (AMU) and farm and animal related parameters were determined. Results show similar relative abundances in farm dust as in feces and a significant positive association (ranging between 0.21 and 0.82) between the two reservoirs. AMU in pigs was positively associated with ARG abundances in dust from the same stable. Higher biosecurity standards were associated with lower relative ARG abundances in poultry and higher relative ARG abundances in pigs. Lower absolute ARG levels in dust were driven by, among others, summer season and certain bedding materials for poultry, and lower animal density and summer season for pigs. This study indicates different pathways that contribute to shaping the dust resistome in livestock farms, related to dust generation, or affecting the bacterial microbiome. Farm dust is a large reservoir of ARGs from which transmission to bacteria in other reservoirs can possibly occur. The identified determinants of ARG abundances in farm dust can guide future research and potentially farm management policy.202235033551
7119150.9997Assessing the benefits of composting poultry manure in reducing antimicrobial residues, pathogenic bacteria, and antimicrobial resistance genes: a field-scale study. The poultry industry in the European Union produces 13 million tons of manure annually, which represents a major health and environmental challenge. Composting is an environmental-friendly technique for the management of manure, but there are few studies about antibiotic residues and antimicrobial resistances at a field scale. The goal of this study was to determine if the composting of poultry manure at a field scale would result in the reduction of antibiotic residues, pathogenic bacteria, and antibiotic resistance genes (ARGs) in the final fertilizer product. A 10-week composting of poultry manure spiked with enrofloxacin, doxycycline, and ciprofloxacin was performed. The determination of antibiotics residues and 22 selected ARGs was carried out together with the identification of bacteria by metagenomics. In the case of ciprofloxacin and doxycycline, a 90% decrease was observed after composting for 3 weeks. Sixteen ARGs were detected at the beginning of the experiment; 12 of them decreased from week 0 to week 10 (reduction of 73.7-99.99%). The presence of potentially pathogenic bacteria, such as, Campylobacter coli or commensal bacteria such as Escherichia coli decreases along the composting process. In conclusion, 10-week composting of poultry manure promotes the reduction of antibiotic residues and most of the ARGs and pathogenic bacteria.202032399873
6839160.9997Bioaerosol is an important transmission route of antibiotic resistance genes in pig farms. Although pig farms are hotspots of antibiotic resistance due to intensive use of antibiotics, little is known about the abundance, diversity and transmission of airborne antibiotic resistance genes (ARGs). This study reports that bioaerosol is an important spread route of ARGs in pig farms. ARGs, mobile genetic elements (MGEs), and bacterial communities were investigated in both air and feces samples during winter and summer. The average concentration of airborne ARGs and MGEs during winter is higher than that during summer when using the ventilation system. The tetM is identified as the predominant airborne ARG with abundance of 6.3 ± 1.2 log copies/m(3). Clostridium and Streptococcus are two dominant bacteria and several opportunistic pathogens are detected in air samples. High temperature is favorable for more diverse bacterial communities, but relative humidity has negative effects. The wind speed promotes the spread of airborne ARGs. The network analysis results show the average fecal contribution to airborne bacteria is 19.9% and 59.4% during summer and winter, respectively. Horizontal gene transfer plays an important role in the dissemination of airborne ARGs during winter (77.8% possibility), while a lower possibility of 12.0% in summer.202133864959
3204170.9997Spread of airborne antibiotic resistance from animal farms to the environment: Dispersal pattern and exposure risk. Animal farms have been considered as the critical reservoir of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). Spread of antibiotic resistance from animal farms to the surrounding environments via aerosols has become a growing concern. Here we investigated the dispersal pattern and exposure risk of airborne ARGs (especially in zoonotic pathogens) in the environment of chicken and dairy farms. Aerosol, dust and animal feces samples were collected from the livestock houses and surrounding environments (upwind and downwind areas) for assessing ARG profiles. Antibiotic resistance phenotype and genotype of airborne Staphylococcus spp. was especially analyzed to reveal the exposure risk of airborne ARGs. Results showed that airborne ARGs were detected from upwind (50 m/100 m) and downwind (50 m/100 m/150 m) air environment, wherein at least 30% of bacterial taxa dispersed from the animal houses. Moreover, atmospheric dispersion modeling showed that airborne ARGs can disperse from the animal houses to a distance of 10 km along the wind direction. Clinically important pathogens were identified in airborne culturable bacteria. Genus of Staphylococcus, Sphingomonas and Acinetobacter were potential bacterial host of airborne ARGs. Airborne Staphylococcus spp. were isolated from the environment of chicken farm (n = 148) and dairy farm (n = 87). It is notable that all isolates from chicken-related environment were multidrug-resistance (>3 clinical-relevant antibiotics), with more than 80% of them carrying methicillin resistance gene (mecA) and associated ARGs and MGEs. Presence of numerous ARGs and diverse pathogens in dust from animal houses and the downwind residential areas indicated the accumulation of animal feces origin ARGs in bioaerosols. Employees and local residents in the chick farming environment are exposed to chicken originated ARGs and multidrug resistant Staphylococcus spp. via inhalation. This study highlights the potential exposure risks of airborne ARGs and antibiotic resistant pathogens to human health.202234673316
5300180.9997From Pig Breeding Environment to Subsequently Produced Pork: Comparative Analysis of Antibiotic Resistance Genes and Bacterial Community Composition. It is well verified that pig farms are an important reservoir and supplier of antibiotic resistance genes (ARGs). However, little is known about the transmission of ARGs between the breeding environment and subsequently produced pork. This study was conducted to investigate if ARGs and associated host bacteria spread from the breeding environment onto the meat through the food production chain. We thus analyzed the occurrence and abundance of ARGs, as well as comparing both ARG and bacterial community compositions in farm soil, pig feces and pork samples from a large-scale pig farm located in Xiamen, People's Republic of China. Among the 26 target ARGs, genes conferring resistance to sulfonamide, trimethoprim, aminoglycoside, chloramphenicol, macrolide, florfenicol, and tetracycline were observed at high frequency in both the pig breeding environment and pork. The prevalence of ARGs in pork was surprisingly consistent with breeding environments, especially between the pork and feces. The relative abundance of 10 representative ARGs conferring resistance to six classes of antibiotics ranged from 3.01 × 10(-1) to 1.55 × 10(-6) copies/16S rRNA copies. The ARGs conferring resistance to sulfanilamide (sulI and sulII), aminoglycoside (aadA), and tetracycline [tet(A) and tet(M)] were most highly abundant across most samples. Samples from feces and meat possessed a higher similarity in ARG compositions than samples from the farms soil. Enterobacteriaceae found on the meat samples were further identical with previously isolated multidrug-resistant bacteria from the same pig farm. Our results strongly indicate that ARGs can be potentially spreading from pig breeding environment to meat via the pork industry chain, such as feed supply, pig feeding and pork production.201930761096
7413190.9997Fecal antibiotic resistance genes were transferred through the distribution of soil-lettuce-snail food chain. Massive antibiotic resistance genes (ARG) were detected in the soil modified by manure, which may affect human life safety through the food chain. However, the transmission of ARGs through the soil-plant-animal food chain is still unclear. Therefore, this study used high-throughput quantitative PCR technology to explore the effects of pig manure application on ARGs and bacterial communities in soil, lettuce phyllosphere, and snail excrement. The results showed that a total of 384 ARGs and 48 MEGs were detected in all samples after 75 days of incubation. The diversity of ARGs and MGEs in soil components increased significantly by 87.04% and 40% with the addition of pig manure. The absolute abundance of ARGs in the phyllosphere of lettuce was significantly higher than that of the control group, with a growth rate of 212.5%. Six common ARGs were detected between the three components of the fertilization group, indicating that there was internal transmission of fecal ARGs between the trophic levels of the food chain. Firmicutes and Proteobacteria were identified as the dominant host bacteria in the food chain system, which were more likely to be used as carriers of ARGs to promote the spread of resistance in the food chain. The results were used to assess the potential ecological risks of livestock and poultry manure. It provides theoretical basis and scientific support for the formulation of ARG prevention and control policies.202337434056