Airborne bacterial community and antibiotic resistome in the swine farming environment: Metagenomic insights into livestock relevance, pathogen hosts and public risks. - Related Documents




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717201.0000Airborne bacterial community and antibiotic resistome in the swine farming environment: Metagenomic insights into livestock relevance, pathogen hosts and public risks. Globally extensive use of antibiotics has accelerated antimicrobial resistance (AMR) in the environment. As one of the biggest antibiotic consumers, livestock farms are hotspots in AMR prevalence, especially those in the atmosphere can transmit over long distances and pose inhalation risks to the public. Here, we collected total suspended particulates in swine farms and ambient air of an intensive swine farming area. Bacterial communities and antibiotic resistomes were analyzed using amplicon and metagenomic sequencing approaches. AMR risks and inhalation exposure to potential human-pathogenic antibiotic-resistant bacteria (HPARB) were subsequently estimated with comparison to the reported hospital samples. The results show that swine farms shaped the airborne bacterial community by increasing abundances, reducing diversities and shifting compositions. Swine feces contributed 77% of bacteria to swine farm air, and about 35% to ambient air. Airborne antibiotic resistomes in swine farms mainly conferred resistance to tetracyclines, aminoglycosides and lincosamides, and over 48% were originated from swine feces. Distinct to the hospital air, Firmicutes were dominant bacteria in swine farming environments with conditional pathogens including Clostridium, Streptococcus and Aerococcus being major hosts of antibiotic resistance genes (ARGs). Therein, genomes of S. alactolyticus carrying (transposase/recombinase-associated) ARGs and virulence factor genes were retrieved from the metagenomes of all swine feces and swine farm air samples, but they were not detected in any hospital air samples. This suggests the indication of S. alactolyticus in swine farming environments with potential hazards to human health. Swine farm air faced higher AMR risks than hospital air and swine feces. The inhalation intake of HPARB by a swine farm worker was about three orders of magnitude higher than a person who works in the hospital. Consequently, this study depicted atmospheric transmission of bacteria and antibiotic resistomes from swine feces to the environment.202336680804
717310.9999Animal farms are hot spots for airborne antimicrobial resistance. Animal farms are known reservoirs for environmental antimicrobial resistance (AMR). However, knowledge of AMR burden in the air around animal farms remains disproportionately limited. In this study, we characterized the airborne AMR based on the quantitative information of 30 antimicrobial resistance genes (ARGs), four mobile genetic elements (MGEs), and four human pathogenic bacteria (HPBs) involving four animal species from 20 farms. By comparing these genes with those in animal feces, the distinguishing features of airborne AMR were revealed, which included high enrichment of ARGs and their potential mobility to host HPBs. We found that depending on the antimicrobial class, the mean concentration of airborne ARGs in the animal farms ranged from 10(2) to 10(4) copies/m(3) and was accompanied by a considerable intensity of MGEs and HPBs (approximately 10(3) copies/m(3)). Although significant correlations were observed between the ARGs and bacterial communities of air and fecal samples, the abundance of target genes was generally high in fine inhalable particles (PM2.5), with an enrichment ratio of up to 10(2) in swine and cattle farms. The potential transferability of airborne ARGs was universally strengthened, embodied by a pronounced co-occurrence of ARGs-MGEs in air compared with that in feces. Exposure analysis showed that animal farmworkers may inhale approximately 10(4) copies of human pathogenic bacteria-associated genera per day potentially carrying highly transferable ARGs, including multidrug resistant Staphylococcus aureus. Moreover, PM2.5 inhalation posed higher human daily intake burdens of some ARGs than those associated with drinking water intake. Overall, our findings highlight the severity of animal-related airborne AMR and the subsequent inhalation exposure, thus improving our understanding of the airborne flow of AMR genes from animals to humans. These findings could help develop strategies to mitigate the human exposure and dissemination of ARGs across different media.202235985594
717520.9998Key Contribution and Risk of Airborne Antibiotic Resistance: Total Suspended Particles or Settled Dust? The atmosphere is an important environmental medium in spreading antimicrobial resistance (AMR) in animal farming systems, yet the exposure risks associated with airborne pathways remain underexplored. This study employed metagenomic sequencing to investigate the airborne transmission of AMR in chicken farms (i.e., chicken feces, total suspended particles (TSP), and dust) and its exposure risks on the gut and nasal cavities of workers, office staff, and nearby villagers. Results revealed that TSP exhibited greater abundance, diversity, and transfer potential of antibiotic resistance genes (ARGs) compared to dust. The abundance of airborne resistome decreased with distance from the chicken house, and ARGs were estimated to spread up to 9.48 km within 1 h. While the gut resistome of workers and villagers showed limited differences, emerging tet(X) variants and high-risk dfrA remain future concerns. More nasal resistome was attributable to TSP compared to dust. Workers faced significantly higher inhalable exposures to antibiotic-resistant bacteria (ARB) and human pathogenic antibiotic-resistant bacteria (HPARB), exceeding those of office staff and villagers by an order of magnitude. We also compiled lists of high-risk and potential-risk airborne ARGs to inform monitoring. These findings highlight the need for regular air disinfection in animal farms and better protective measures for workers.202540434009
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
717440.9998Metagenomic analysis deciphers airborne pathogens with enhanced antimicrobial resistance and virulence factors in composting facilities. The composting process has been shown to effectively reduce antimicrobial resistance (AMR) in animal manure, but its influence on surrounding airborne AMR remains unknown, particularly with regard to human-pathogenic antibiotic-resistant bacteria (HPARB). In this study, air and paired compost samples were collected from a full-scale composting facility, and the antibiotic resistome, microbiome, and HPARB were systematically analyzed in both two habitats using metagenomic analysis. Current result uncovered the profiles of HPARB in air, showing that significantly more airborne HPARB were assembled than that in compost samples. Airborne pathogens harboredan increased abundance and diversity of antibiotic resistance genes (ARGs) and virulence factor genes (VFGs) in comparison with compost-borne HPARB. The core antibiotic resistome represents 18.58% of overall ARG subtypes, contributing to 86.31% of ARG abundance. A higher number of enriched core ARGs (2.16- to 13.36-times higher), including mexF, tetW, and vanS, were observed in air samples compared to compost samples. As an important human pathogen, Mycobacterium tuberculosis was prevalent in the air and carried more ARG (6) and VFG (130) subtypes than those in compost. A significantly higher risk score was detected for airborne AMR in the composting facility compared to that in hospital and urban environments. This study revealed the enhanced airborne HPARB through comparative experiments between air and composting habitats. It highlighted the unrecognized AMR risks associated with air in composting site and provided a scientific basis for accurately assessing health outcomes caused by occupational exposure.202540472755
321850.9998Airborne bacterial communities in the poultry farm and their relevance with environmental factors and antibiotic resistance genes. The accelerating occurrence and environmental dissemination of bacteria, gas pollutants and antibiotic resistance genes (ARGs) in aerosols of poultry farms have become emerging environmental issues due to their potential threat to animals, workers, and the communities located near such farms. Here, aerosol samples were gathered from inside and outside of the chicken house in winter with a transportable high-flow bioaerosol sampler. Then, 16S rRNA gene amplicon sequencing was used to categorize the bacteria in air samples, and the abundance of 12 ARG subtypes was researched via the real-time quantitative polymerase chain reaction (qPCR). Results indicated that the bacterial richness and diversity and total absolute abundance of ARGs were similar in the bioaerosols from indoor and downwind site of the poultry farm. The zoonotic pathogens, Staphylococcus and Corynebacterium, were detected both inside and outside of the chicken house, and the four most abundant target genes were bla(TEM), tetQ, ermB and sul1 in aerosols. Moreover, the correlation between the bacterial communities and environmental factors, such as NH(3) and H(2)S concentrations, wind speed, temperature and relative humidity, was analyzed. The result revealed that the indoor bacteria community was positively associated with temperature and concentrations of air pollutants (NH(3) and H(2)S), and could spread from confinement buildings to the ambient atmosphere through wind. In addition, the network analysis result showed that the airborne bacteria might significantly contribute in shaping the ARGs' profiles in bioaerosol from inside and outside of the poultry house. Overall, our results revealed the airborne bacterial communities and their associated influencing factors in the micro-environment (inside of the chicken house and nearby the boundary of the farm), and brought a new perspective for studying the gas pollutants and bioaerosol from poultry farms in winter.202235850323
327760.9998Airborne antibiotic resistome and human health risk in railway stations during COVID-19 pandemic. Antimicrobial resistance is recognized as one of the greatest public health concerns. It is becoming an increasingly threat during the COVID-19 pandemic due to increasing usage of antimicrobials, such as antibiotics and disinfectants, in healthcare facilities or public spaces. To explore the characteristics of airborne antibiotic resistome in public transport systems, we assessed distribution and health risks of airborne antibiotic resistome and microbiome in railway stations before and after the pandemic outbreak by culture-independent and culture-dependent metagenomic analysis. Results showed that the diversity of airborne antibiotic resistance genes (ARGs) decreased following the pandemic, while the relative abundance of core ARGs increased. A total of 159 horizontally acquired ARGs, predominantly confering resistance to macrolides and aminoglycosides, were identified in the airborne bacteria and dust samples. Meanwhile, the abundance of horizontally acquired ARGs hosted by pathogens increased during the pandemic. A bloom of clinically important antibiotic (tigecycline and meropenem) resistant bacteria was found following the pandemic outbreak. 251 high-quality metagenome-assembled genomes (MAGs) were recovered from 27 metagenomes, and 86 genera and 125 species were classified. Relative abundance of ARG-carrying MAGs, taxonomically assigned to genus of Bacillus, Pseudomonas, Acinetobacter, and Staphylococcus, was found increased during the pandemic. Bayesian source tracking estimated that human skin and anthropogenic activities were presumptive resistome sources for the public transit air. Moreover, risk assessment based on resistome and microbiome data revealed elevated airborne health risks during the pandemic.202336731187
320570.9998Determinants 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
717680.9998Significant higher airborne antibiotic resistance genes and the associated inhalation risk in the indoor than the outdoor. Inhalation of airborne antibiotic resistance genes (ARGs) can lead to antimicrobial resistance and potential health risk. In modern society, increasing individuals stay more indoors, however, studies regarding the exposure to airborne ARGs in indoor environments and the associated risks remain limited. Here, we compared the variance of aerosol-associated ARGs, bacterial microbiomes, and their daily intake (DI) burden in dormitory, office, and outdoor environments in a university in Tianjin. The results indicated that compared to outdoor aerosols, indoors exhibited significantly higher absolute abundance of both ARG subtypes and mobile genetic elements (MGEs) (1-7 orders of magnitude), 16S rRNA genes (2-3 orders), and total culturable bacteria (1-3 orders). Furthermore, we observed that significantly different airborne bacterial communities are the major drivers contributing to the variance of aerosol-associated ARGs in indoor and outdoor aerosols. Notably, the high abundances of total bacteria, potential pathogenic genera, and ARGs (particularly those harbored by pathogens) in indoor and outdoor aerosols, especially in indoors, may pose an increased exposure risk via inhalation. The successful isolation of human pathogens such as Elizabethkingia anopheles, Klebsiella pneumonia, and Delftia lacustris resistant to the "last-resort" antibiotics carbapenems and polymyxin B from indoor aerosols further indicated an increased exposure risk in indoors. Together, this study highlights the potential risks associated with ARGs and their inhalation to human health in indoor environments.202133120141
317690.9998Comprehensive profiling and risk assessment of antibiotic resistance genes in a drinking water watershed by integrated analysis of air-water-soil. The prevalence of antibiotic resistance genes (ARGs) in diverse habitats threatens public health. Watersheds represent critical freshwater ecosystems that interact with both the soil and atmosphere. However, a holistic understanding of ARGs distribution across these environmental media is currently inadequate. We profiled ARGs and bacterial communities in air-water-soil in the same watershed area during four seasons using high-throughput qPCR and 16S rRNA gene sequencing. Our findings demonstrated that aminoglycoside resistance genes (58.5%) were dominant in water, and multidrug resistance genes (55.2% and 54.2%) were dominant in soil and air. Five ARGs and nineteen bacterial genera were consistently detected in all samples, were named as shared genes or bacteria. Co-occurrence Network analysis revealed the co-occurrence module of resistance genes, mobile genetic elements (MGEs), and potential bacterial hosts, indicating that shared genes and bacteria may persist and co-spread across different environmental media. The risk assessment framework, based on ARGs' abundance, detection rate, and mobility, identified 33 high-risk ARGs. This is essential to evaluate the health risks of ARGs and to develop strategies to limit the threat of antibiotic resistance. Our study offers new insights into the risks associated with ARGs in the environment and suggests that ARGs may depend on specific bacterial cohabitants that co-exist with MGEs to facilitate their spread across environmental interfaces.202337742410
3216100.9998Effects 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
3204110.9998Spread 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
6839120.9998Bioaerosol 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
7171130.9998Household waste-specific ambient air shows greater inhalable antimicrobial resistance risks in densely populated communities. Household waste is a hotspot of antibiotic resistance, which can be readily emitted to the ambient airborne inhalable particulate matters (PM(10)) during the day-long storage in communities. Nevertheless, whether these waste-specific inhalable antibiotic resistance genes (ARGs) are associated with pathogenic bacteria or pose hazards to local residents have yet to be explored. By high-throughput metagenomic sequencing and culture-based antibiotic resistance validation, we analyzed 108 airborne PM(10) and nearby environmental samples collected across different types of residential communities in Shanghai, the most populous city in China. Compared to the cold-dry period, the warm-humid season had significantly larger PM(10)-associated antibiotic resistomes in all types of residential communities (T-test, P < 0.001), most of airborne ARGs in which were estimatedly originated from disposed household waste (∼ 30 %). In addition, the airborne bacteria were assembled in a deterministic approach (iCAMP, P < 0.01), where the waste-specific bacteria taxa including Acinetobacter, Pseudomonas, Rhodococcus, and Kocuria had the predominant niches in the airborne microbial assemblages. Notably, these waste-sourced bacteria were also identified as the primary airborne hosts of ARGs encoding the aminoglycoside resistances. Among them, some antibiotic resistant human pathogens, such as Pseudomonas aeruginosa and Acinetobacter baumannii, not only exhibited higher ARG horizontal gene transfer (HGT) potential across the microbial assemblages, but also imposed direct infection risks on the local residents by 2 min inhalation exposure per day. When the daily exposure duration increased to 11 min, the infection-induced illness burden became unignorably high, especially in densely populated urban communities, being twofold greater than rural areas.202539862584
6857140.9998Metagenomic analysis reveals patterns and hosts of antibiotic resistance in different pig farms. In actual production environments, antibiotic-resistant genes (ARGs) are abundant in pig manure, which can form transmission chains through animals, the environment, and humans, thereby threatening human health. Therefore, based on metagenomic analysis methods, ARGs and mobile genetic elements (MGEs) were annotated in pig manure samples from 6 pig farms in 3 regions of Shanxi Province, and the potential hosts of ARGs were analyzed. The results showed that a total of 14 ARG types were detected, including 182 ARG subtypes, among which tetracycline, phenol, aminoglycoside, and macrolide resistance genes were the main ones. ARG profiles, MGE composition, and microbial communities were significantly different in different regions as well as between different pig farms. In addition, Anaerobutyricum, Butyrivibrio, and Turicibacter were significantly associated with multiple ARGs, and bacteria such as Prevotella, Bacteroides, and the family Oscillospiraceae carried multiple ARGs, suggesting that these bacteria are potential ARG hosts in pig manure. Procrustes analysis showed that bacterial communities and MGEs were significantly correlated with ARG profiles. Variation partitioning analysis results indicated that the combined effect of MGEs and bacterial communities accounted for 64.08% of resistance variation and played an important role in ARG profiles. These findings contribute to our understanding of the dissemination and persistence of ARGs in actual production settings, and offer some guidance for the prevention and control of ARGs contamination.202336826766
6867150.9998Comparative analysis of characteristics of antibiotic resistomes between Arctic soils and representative contaminated samples using metagenomic approaches. Antibiotic resistance is one of the most concerned global health issues. However, comprehensive profiles of antibiotic resistance genes (ARGs) in various environmental settings are still needed to address modern antibiotic resistome. Here, Arctic soils and representative contaminated samples from ARG pollution sources were analyzed using metagenomic approaches. The diversity and abundance of ARGs in Arctic soils were significantly lower than those in contaminated samples (p < 0.01). ARG profiles in Arctic soils were featured with the dominance of vanF, ceoB, and bacA related to multidrug and bacitracin, whereas those from ARG pollution sources were characterized by prevalent resistance to anthropogenic antibiotics such as sulfonamides, tetracyclines, and beta-lactams. Mobile genetic elements (MGEs) were found in all samples, and their abundance and relatedness to ARGs were both lower in Arctic soils than in polluted samples. Significant relationships between bacterial communities and ARGs were observed (p < 0.01). Cultural bacteria in Arctic soils had clinically-concerned resistance to erythromycin, vancomycin, ampicillin, etc., but ARGs relevant to those antibiotics were undetectable in their genomes. Our results suggested that Arctic environment could be an important reservoir of novel ARGs, and antibiotic stresses could cause ARG pollution via horizontal gene transfer and enrichment of resistant bacteria.202438452676
6863160.9998Prevalence, source and risk of antibiotic resistance genes in the sediments of Lake Tai (China) deciphered by metagenomic assembly: A comparison with other global lakes. Lakes are one of the natural reservoirs of antibiotic resistance genes (ARGs) in environments. Long retention times in lakes potentially allow ARGs to persist and may create increased opportunities for the emergence of resistant pathogens. In this study, we investigated the prevalence, source and dissemination risk of ARGs in the sediments of a typical urban lake, Lake Tai (China) which has been a drastic example of water pollution with eutrophication in the world due to its proliferated cyanobacterial blooms. High-throughput profilings of ARGs in the sediments of Lake Tai were characterized with metagenomic assembly, and were compared with those in other global lakes from Australia, Canada, Indonesia, Rwanda and the United States of America. The hosts of ARGs in the sediments of Lake Tai were explored based on the taxonomic annotation of ARG-carrying contigs and network analysis, and a novel recently-discovered crAssphage was employed for source tracking of resistance bacteria. Meanwhile, the potential resistome risk was identified by projecting the co-occurrence of acquired ARGs, mobile genetic elements (MGEs) and human bacterial pathogens into a three-dimensional exposure space. Results showed 321 ARG subtypes belonging to 21 ARG types were detected in the sediments of Lake Tai, dominated by multidrug, macrolide-lincosamide-streptogramin, bacitracin, quinolone, mupirocin and trimethoprim resistance genes. Relatively, the ARG levels in the sediments of Lake Tai were significantly higher than those in other global lakes. Source tracking showed the coverages of detected crAssphage in the sediments of Lake Tai were positively correlated with the total ARG coverage, suggesting the contribution of human fecal contamination to the prevalence of ARGs in this lake. It should be noted that the co-occurrence ratio of ARGs, MGEs and human pathogens in the sediments of Lake Tai was higher than that in other global lakes, likely indicating a higher risk for the resistance dissemination in the China's third largest freshwater lake.201930928850
3207170.9998Dissemination of antibiotic resistance genes from aboveground sources to groundwater in livestock farms. Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are prevalent in various environments on livestock farms, including livestock waste, soil, and groundwater. Contamination of groundwater by ARB and ARGs in livestock farms is a growing concern as it may have potentially huge risks to human health. However, the source of groundwater-borne ARB and ARGs in animal farms remains largely unknown. In this study, different types of samples including groundwater and its potential contamination sources from aboveground (pig feces, wastewater, and soil) from both working and abandoned swine feedlots in southern China were collected and subjected to metagenomic sequencing and ARB isolation. The source tracking based on metagenomic analysis revealed that 56-95 % of ARGs in groundwater was attributable to aboveground sources. Using metagenomic assembly, we found that 45 ARGs predominantly conferring resistance to aminoglycosides, sulfonamides, and tetracyclines could be transferred from the aboveground sources to groundwater, mostly through plasmid-mediated horizontal gene transfer. Furthermore, the full-length nucleotide sequences of sul1, tetA, and TEM-1 detected in ARB isolates exhibited the close evolutionary relationships between aboveground sources and groundwater. Some isolated strains of antibiotic-resistant Pseudomonas spp. from aboveground sources and groundwater had the high similarity (average nucleotide identity > 99 %). Notably, the groundwater-borne ARGs were identified as mainly carried by bacterial pathogens, potentially posing risks to human and animal health. Overall, this study underscores the dissemination of ARGs from aboveground sources to groundwater in animal farms and associated risks.202438598950
6837180.9998Coexistence of antibiotic resistance genes, fecal bacteria, and potential pathogens in anthropogenically impacted water. Microbial indicators are often used to monitor microbial safety of aquatic environments. However, information regarding the correlation between microbial indicators and ecotoxicological factors such as potential pathogens and antibiotic resistance genes (ARGs) in anthropogenically impacted waters remains highly limited. Here, we investigated the bacterial community composition, potential pathogens, ARGs diversity, ARG hosts, and horizontal gene transfer (HGT) potential in urban river and wastewater samples from Chaohu Lake Basin using 16S rRNA and metagenomic sequencing. The composition of the microbial community and potential pathogens differed significantly in wastewater and river water samples, and the total relative abundance of fecal indicator bacteria was positively correlated with the total relative abundance of potential pathogens (p < 0.001 and Pearson's r = 0.758). Network analysis indicated that partial ARG subtypes such as dfrE, sul2, and PmrE were significantly correlated with indicator bacteria (p < 0.05 and Pearson's r > 0.6). Notably, Klebsiella was the indicator bacteria significantly correlated with 4 potential pathogens and 14 ARG subtypes. ARGs coexisting with mobile gene elements were mainly found in Thauera, Pseudomonas, Escherichia, and Acinetobacter. Next-generation sequencing (NGS) can be used to conduct preliminary surveys of environmental samples to access potential health risks, thereby facilitating water resources management.202235175529
3219190.9998Airborne 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