Bacterial Heavy-Metal and Antibiotic Resistance Genes in a Copper Tailing Dam Area in Northern China. - Related Documents




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751701.0000Bacterial Heavy-Metal and Antibiotic Resistance Genes in a Copper Tailing Dam Area in Northern China. Heavy metal resistance genes (MRGs) and antibiotic resistance genes (ARGs) in bacteria can respond to the inducement of heavy metals. However, the co-occurrence of MRGs and ARGs in the long-term heavy metal contaminated area is still poorly understood. Here, we investigated the relationship between the abundance of soil bacteria MRGs, ARGs and heavy metal pollution in a copper tailing dam area of northern China. We found that arsC and ereA genes coding for resistance mechanisms to arsenic and to macrolides, respectively, are the most abundant MRG and ARG in the study area. The abundance of MRGs is positively correlated with cadmium (Cd) concentration, and this indicates the importance of Cd in the selection of MRGs. The network analysis results show that sulII and MRGs co-occur and copB occur with ARGs, which suggests that MRGs and ARGs can be co-selected in the soil contaminated by heavy metal. The network analysis also reveals the co-occurrence of Cd and MRGs, and thus heavy metal with a high 'toxic-response' factor can be used as the indicator of MRGs. This study improves the understanding of the relationship between bacterial resistance and multi-metal contamination, and underlies the exploration of the adaptive mechanism of microbes in the multi-metal contaminated environment.201931481945
689410.9999Profiles of antibiotic- and heavy metal-related resistance genes in animal manure revealed using a metagenomic analysis. Farmed animals produce excrement containing excessive amounts of toxic heavy metals as a result of consuming compound feed as well as receiving medical treatments, and the presence of these heavy metals may aggravate the risk of spreading drug-resistance genes through co-selection during manure treatment and application processes. However, research on the association between heavy metals and antimicrobial resistance is still lacking. In this study, metagenomic sequencing was used to explore the effects of the co-selection of environmentally toxic heavy metals on the resistome in manure. A relevance network analysis showed that metal-resistance genes (MRGs), especially for copper (Cu) and zinc (Zn), were positively correlated with multiple types of antibiotic-resistance genes (ARGs) and formed a complex network. Most bacteria that co-occurred with both MRGs and ARGs simultaneously are members of Proteobacteria and accounted for 54.7% of the total microbial species in the relevance network. The remaining bacteria belonged to Firmicutes, Bacteroidetes and Actinobacteria. Among the four phyla, Cu- and Zn-resistance genes had more complex correlations with ARGs than other MRG types, reflecting the occurrence of ARG co-selection under the selective pressure of high Cu and Zn levels. In addition, approximately 64.8%, 59.1% and 68.4% of MRGs that correlated with the presence of plasmids, viruses and prophages, respectively, are Cu- or Zn-resistant, and they co-occurred with various ARGs, indicating that mobile genetic elements participate in mediating ARG co-selection in response to Cu and Zn pressure. The results indicated that the use of heavy-metal additives in feed induces the increases of drug resistance genes in manure through co-selection, aggravating the risk of antimicrobial resistance diffusion from animal farm to manure land applications.202235617901
751820.9999Deciphering the toxic effects of metals in gold mining area: Microbial community tolerance mechanism and change of antibiotic resistance genes. Mine tailing dumps represent significant threats to ecological environments due to the presence of toxic substances. The present work investigated the relationship among microbial activity, the community, antibiotic resistance genes (ARGs) and trace metals in soil surrounding gold mine tailings. Using microbial metabolic activity and high-throughput sequencing analysis, we found the trace metals Cd and Hg could be main factors influencing the microbial community. According to bacterial co-occurrence pattern analysis, the effects of total cadmium and total mercury on bacterial diversity are potentially mediated by influencing bacteria community in the keystone module II. Additionally, most of metal-resistant bacteria belong to Actinobacteria and Proteobacteria, and the metal tolerance suggested to be linked with various functions including replication, recombination and repair, as well as inorganic ion transport and metabolism based on PICRUSt2 analysis. We also found that metals generated by mining activity may trigger the co-selection of antibiotic resistance in the phyla Actinobacteria and Proteobacteria due to co-resistance or cross resistance. Additionally, PLS-PM analysis revealed that metals could indirectly affect ARGs by influencing bacterial diversity in gold mining areas.202032678731
689530.9998Effects of heavy metals pollution on the co-selection of metal and antibiotic resistance in urban rivers in UK and India. Heavy metal pollution and the potential for co-selection of resistance to antibiotics in the environment is growing concern. However, clear associations between heavy metals and antibiotic resistance in river systems have not been developed. Here we investigated relationships between total and bioavailable heavy metals concentrations; metal resistance gene (MRG) and antibiotic resistance gene (ARG) abundances; mobile genetic elements; and the composition of local bacterial communities in low and high metal polluted rivers in UK and India. The results indicated that MRGs conferring resistance to cobalt (Co) and nickel (Ni) (rcnA), and Co, zinc (Zn), and cadmium (Cd) (czcA), and ARGs conferring resistance to carbapenem and erythromycin were the dominating resistant genes across the samples. The relative MRGs, ARGs, and integrons abundances tended to increase at high metal polluted environments, suggesting high metals concentrations have a strong potential to promote metal and antibiotic resistance by horizontal gene transmission and affecting bacterial communities, leading to the development of multi-metal and multi-antibiotic resistance. Network analysis demonstrated the positive and significant relationships between MRGs and ARGs as well as the potential for integrons playing a role in the co-transmission of MRGs and ARGs (r > 0.80, p < 0.05). Additionally, the major host bacteria of various MRGs and ARGs that could be accountable for greater MRGs and ARGs levels at high metal polluted environments were also identified by network analysis. Spearman's rank-order correlations and RDA analysis further confirm relationships between total and bioavailable heavy metals concentrations and the relative MRG, ARG, and integron abundances, as well as the composition of related bacterial communities (r > 0.80 (or < -0.80), p < 0.05). These findings are critical for assessing the possible human health concerns associated with metal-driven antibiotic resistance and highlight the need of considering metal pollution for developing appropriate measures to control ARG transmission.202235491000
690240.9998Antibiotic resistance genes in surface water and groundwater from mining affected environments. Mining activities are known to generate a large amount of mine tailings and acid mine drainage which contain varieties of heavy metals. Heavy metals play an important role in co-selection for bacterial antibiotic resistance. However, the characteristics of antibiotic resistance genes (ARGs) in mining-affected water environments are still unclear. Here we investigated the pollution of metals, profiles of ARGs, mobile genetic elements (MGEs) and microbial community in mining-affected surface water and groundwater. The results showed that in the tested water samples, the concentrations of Zn and Mn were the highest, and Ni was the lowest. Higher abundances of ARGs with great proportion of sulfonamides, chloramphenicols and tetracyclines resistance genes were found in mining-affected water when compared with those without mining activities. Additionally, there were positive correlations between heavy metals (especially Ni, Zn and Mn) and these ARGs. Linear regression analysis suggested that MGEs were positively correlated with ARGs. In addition, total phosphorus was correlated with ARGs (p < 0.05). The microbial community was different between the mining-affected water and the reference (p < 0.05). Proteobacteria, Bacteroidetes and Actinobacteria were dominant phyla in the surface water and groundwater. Network analysis showed that many ARGs were significantly associated with these dominant bacteria, which suggested they might be potential hosts for these ARGs. These findings provide a clear evidence that the mining activities in the study area had a significant impact on surface water and groundwater to different degrees.202133571766
751650.9998Functional gene array-based analysis of microbial communities in heavy metals-contaminated lake sediments. Lake DePue (IL, USA) has been contaminated for > 80 years by an adjacent Zn-smelting facility. Previous work indicated that sulfate reduction increased and biomass declined as pore-water metal concentrations increased, while 16S rRNA gene profiles remained relatively stable. To better understand this phenomenon, the sediment microbial community structure and functional potential were investigated using a functional gene microarray (GeoChip) targeting > 10,000 functional genes. Nonmetric multidimensional scaling and clustering analyses showed that the overall community structure was similar across all sites based on the relative abundance of all detected genes, but some individual gene categories did show differences. A subset of sulfate reduction genes (dsr) and the most relevant metal resistance genes were more abundant than other categories and were highly correlated with metal contamination. The most significant correlations were between pore-water metal concentrations and dsr, with Zn, Cd, and Mn as the most predictive for the presence of dsr. These results suggest that metal contamination influences sediment microbial community structure and function by increasing the abundance of relevant metal-resistant and sulfate-reducing populations. These populations therefore appear to contribute significantly to the resistance and stability of the microbial communities throughout the gradient of metal contamination in Lake DePue.201323710534
689260.9998Metagenomic deciphers the mobility and bacterial hosts of antibiotic resistance genes under antibiotics and heavy metals co-selection pressures in constructed wetlands. Both antibiotics and heavy metals exert significant selection pressures on antibiotic-resistance genes (ARGs). This study aimed to investigate the co-selection effects of doxycycline (DC) and cadmium (Cd) on ARGs in constructed wetlands (CWs). The results demonstrated that under antibiotic and heavy metal co-selection pressures, single high concentration DC/Cd or double high, relative abundances of metagenomics assembled genomes all reached 55.1%; meanwhile, the average ratio of ARG-containing contigs located on chromosomes was 61.8% (ranging from 50.4% to 70.6%) suggesting a more stable inheritance of ARGs. Antibiotic and heavy metal co-selection in single high concentration DC/Cd or double high groups stimulate the enrichment of ARG host bacteria, which exhibited complex multiple-resistant patterns accompanied by a host-specific pattern. Additionally, the potential transfer abilities of ARGs mediated by plasmids and integrative and conjugative elements (ICEs) were enhanced under single high-concentration DC/Cd or double high stresses. Together, antibiotic and heavy metal co-selection pressures increased occurrence frequencies of ARGs, MGEs, and their combinations and altered structural communities of ARG host bacteria, increasing the risk of the spread of ARGs. This study was helpful in understanding the dissemination of ARGs and simultaneously preventing the spread of heavy metal-resistant bacteria and ARGs under antibiotic and heavy metal co-selection in small- and micro-wetlands.202539848523
747170.9998Impact of fluoroquinolone and heavy metal pollution on antibiotic resistance maintenance in aquatic ecosystems. BACKGROUND: Freshwater pollution with compounds used during anthropogenic activities could be a major driver of antibiotic resistance emergence and dissemination in environmental settings. Fluoroquinolones and heavy metals are two widely used aquatic pollutants that show a high stability in the environment and have well-known effects on antibiotic resistance selection. However, the impact of these compounds on antibiotic resistance maintenance in aquatic ecosystems remains unknown. In this study, we used a microcosm approach to determine the persistence of two fluoroquinolones (ciprofloxacin, ofloxacin) and two heavy metals (copper and zinc) in the Rhône river over 27 days. In addition, we established links between antibiotic and metal pollution, alone and in combination, and the composition of freshwater bacterial communities, the selection of specific members and the selection and maintenance of antibiotic and metal resistance genes (ARGs and MRGs) using a metagenomics approach. RESULTS: Whereas ofloxacin was detected at higher levels in freshwater after 27 days, copper had the strongest influence on bacterial communities and antibiotic and metal resistance gene selection. In addition, heavy metal exposure selected for some ARG-harboring bacteria that contained MRGs. Our research shows a heavy metal-driven transient co-selection for fluoroquinolone resistance in an aquatic ecosystem that could be largely explained by the short-term selection of Pseudomonas subpopulations harboring both fluoroquinolone efflux pumps and copper resistance genes. CONCLUSION: This research highlights the complexity and compound-specificity of dose-response relationships in freshwater ecosystems and provides new insights into the medium-term community structure modifications induced by overall sub-inhibitory levels of antibiotic and heavy metal pollution that may lead to the selection and maintenance of antibiotic resistance in low-impacted ecosystems exposed to multiple pollutants.202540426239
680680.9998Distribution Pattern and Influencing Factors of Heavy Metal Resistance Genes in the Yellow River Sediments of Henan Section. The transformation of heavy metal resistance genes (MRGs) in the environment has attracted increasing attention in recent years. However, few studies have reported the MRG content in the Yellow River, one of the main irrigation water sources in the North China Plain. In this study, we quantified MRG abundance by a metagenomic approach, and assessed the influence on MRGs of both bioavailable and total heavy metal (HM) content. The results indicate that Cu-resistant genes are the most common genes, and the prevalence of arsM needs more attention. Comamonadaceae is the dominant family in the Yellow River, and the presence of organic pollutants may contribute to the prevalence of Vicinamibacteraceae, Nocardioidaceae, and Flavobacteriacea. The results of the Mantel test and Spearman analysis indicate that both the bioavailable fractions and total content of HMs could have little influence on MRGs. Network analysis results indicate that some dominant bacteria could be the potential hosts of some prevalent MRGs, which may exert an adverse impact on human health.202236078440
746690.9998Effects of heavy metals on the development and proliferation of antibiotic resistance in urban sewage treatment plants. Sewage treatment plants (STPs) are considered as "hotspots" for the emergence and proliferation of antibiotic resistance. However, the impact of heavy metals contamination on dispersal of antibiotic resistance in STPs is poorly understood. This study simultaneously investigated the effect of removal of metal and antibiotic resistance as well as mobile elements at different treatment units of STPs in Delhi, India. Results showed that treatment technologies used in STPs were inefficient for the complete removal of metal and antibiotic resistance, posing an ecological risk of co-selection of antibiotic resistance. The strong correlations were observed between heavy metals, metal and antibiotic resistance, and integrons, implying that antibiotic resistance may be exacerbated in the presence of heavy metals via integrons, and that metal and antibiotic resistance share a common or closely associated mechanism. We quantified an MRG rcnA, conferring resistance to Co and Ni, and identified that it was more abundant than all MRGs, ARGs, integrons, and 16S rRNA, suggesting rcnA could be important in antibiotic resistance dissemination in the environment. The associations between heavy metals, metal and antibiotic resistance, and integrons highlight the need for additional research to better understand the mechanism of co-selection as well as to improve the removal efficacy of current treatment systems.202235724944
6893100.9998Heavy metal and antibiotic resistance in four Indian and UK rivers with different levels and types of water pollution. Heavy metal pollution can enhance the level of antibiotic resistance, posing concerns to ecosystem and public health. Here, we investigated heavy metal concentrations, heavy metal resistant bacteria and antibiotic resistant bacteria and their corresponding resistant genes, and integrons in four different river environments, i.e., low heavy metals and low wastewater, high heavy metals and low wastewater, low heavy metals and high wastewater, and high heavy metals and high wastewater levels. Heavy metals were found to show positive and significant correlations with heavy metal resistance and antibiotic resistance and integrons (r > 0.60, p < 0.05), indicating that heavy metal selective pressure can cause heavy metal and antibiotic resistance to be transmitted simultaneously via integrons, which can result in the development of multi-resistant bacteria in the heavy metal-polluted environments. Moreover, there were significant associations between heavy metal resistance and antibiotic resistance (r > 0.60, p < 0.05), demonstrating heavy metal and antibiotic resistance are connected via a same or related mechanism. Class 1 integrons were found to have strong correlations with heavy metals and heavy metal resistance and antibiotic resistance (r > 0.60, p < 0.05), indicating a higher occurrence of antibiotic resistance co-selection in the heavy metal-polluted environments.202336174689
6903110.9998Heavy Metal Tolerance Genes Associated With Contaminated Sediments From an E-Waste Recycling River in Southern China. Heavy metal pollution that results from electronic waste (e-waste) recycling activities has severe ecological environmental toxicity impacts on recycling areas. The distribution of heavy metals and the impact on the bacteria in these areas have received much attention. However, the diversity and composition of the microbial communities and the characteristics of heavy metal resistance genes (HMRGs) in the river sediments after long-term e-waste contamination still remain unclear. In this study, eight river sediment samples along a river in a recycling area were studied for the heavy metal concentration and the microbial community composition. The microbial community consisted of 13 phyla including Firmicutes (ranging from 10.45 to 36.63%), Proteobacteria (11.76 to 32.59%), Actinobacteria (14.81 to 27.45%), and unclassified bacteria. The abundance of Firmicutes increased along with the level of contaminants, while Actinobacteria decreased. A canonical correspondence analysis (CCA) showed that the concentration of mercury was significantly correlated with the microbial community and species distribution, which agreed with an analysis of the potential ecological risk index. Moreover, manually curated HMRGs were established, and the HMRG analysis results according to Illumina high-throughput sequencing showed that the abundance of HMRGs was positively related to the level of contamination, demonstrating a variety of resistance mechanisms to adapt, accommodate, and live under heavy metal-contaminated conditions. These findings increase the understanding of the changes in microbial communities in e-waste recycling areas and extend our knowledge of the HMRGs involved in the recovery of the ecological environment.202134054770
7042120.9997Response of antibiotic resistance genes abundance by graphene oxide during the anaerobic digestion of swine manure with copper pollution. The pollution of various environments with antibiotic resistance genes (ARGs) is an urgent problem that needs to be addressed, especially in heavy metal-polluted environments. This study investigated the responses of ARGs and mobile genetic elements (MGEs) to the addition of graphene oxide (GO) to swine manure containing a high concentration copper during anaerobic digestion. The total copy numbers of ARGs and MGEs were significantly enhanced by the pressure due to Cu. GO significantly decreased the ARG and MGE copy numbers, where the low GO concentration performed better than the high GO concentration. Network analysis showed that most of the ARGs and MGEs co-occurred and they shared the same major potential host bacteria. The contributions of different factors to ARG abundances were assessed by redundancy analysis and MGEs had the most important effect on the fate of ARGs. Thus, GO may reduce the abundance of ARGs mainly by removing MGEs.201930445329
6432130.9997Antibiotic resistance genes in the coastal atmosphere under varied weather conditions: Distribution, influencing factors, and transmission mechanisms. Antibiotic resistance genes (ARGs) have escalated to levels of concern worldwide as emerging environmental pollutants. Increasing evidence suggests that non-antibiotic antimicrobial substances expedite the spread of ARGs. However, the drivers and mechanisms involved in the generation and spread of ARGs in the atmosphere remain inadequately elucidated. Co-occurrence networks, mantel test analysis, and partial least squares path modeling were used to analyze the symbiotic relationships of ARGs with meteorological conditions, atmospheric pollutants, water-soluble inorganic ions, bacteria, mobile genetic elements (MGEs), antibacterial biocide and metal resistance genes, and to identify the direct drivers of ARGs. The types and abundance of ARGs exhibited different seasonal distribution. Specifically, the types exhibited a strong alignment with the diversity of air masses terrestrial sources, while the abundance displayed a significant positive correlation with both biocide resistance genes (BRGs) and metal resistance genes (MRGs). The contribution of bacterial communities and MGEs to the generation and spread of ARGs was constrained by the low levels of antibiotics in the atmosphere and the existence of "viral intermediates". Conversely, antibacterial biocides and metals influenced mutation rates, cellular SOS responses, and oxidative stress of bacteria, consequently facilitating the generation and spread of ARGs. Moreover, the co-selection among their derivatives, resistance genes, ensured a stable presence of ARGs. The research highlighted the significant impact of residual antimicrobial substances on both the generation and spread of ARGs. Elucidating the sources of aerosols and the co-selection mechanism linking with ARGs, BRGs, and MRGs were crucial for preserving the stability of ARGs in the atmosphere.202539824332
7010140.9997Dynamics 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
6947150.9997Co-occurrence of genes for antibiotic resistance and arsenic biotransformation in paddy soils. Paddy soils are potential hotspots of combined contamination with arsenic (As) and antibiotics, which may induce co-selection of antibiotic resistance genes (ARGs) and As biotransformation genes (ABGs), resulting in dissemination of antimicrobial resistance and modification in As biogeochemical cycling. So far, little information is available for these co-selection processes and specific patterns between ABGs and ARGs in paddy soils. Here, the 16S rRNA amplicon sequencing and high-throughput quantitative PCR and network analysis were employed to investigate the dynamic response of ABGs and ARGs to As stress and manure application. The results showed that As stress increased the abundance of ARGs and mobile genetic elements (MGEs), resulting in dissemination risk of antimicrobial resistance. Manure amendment increased the abundance of ABGs, enhanced As mobilization and methylation in paddy soil, posing risk to food safety. The frequency of the co-occurrence between ABGs and ARGs, the host bacteria carrying both ARGs and ABGs were increased by As or manure treatment, and remarkably boosted in soils amended with both As and manure. Multidrug resistance genes were found to have the preference to be co-selected with ABGs, which was one of the dominant co-occurring ARGs in all treatments, and manure amendment increased the frequency of Macrolide-Lincosamide-Streptogramin B resistance (MLSB) to co-occur with ABGs. Bacillus and Clostridium of Firmicutes are the dominant host bacteria carrying both ABGs and ARGs in paddy soils. This study would extend our understanding on the co-selection between genes for antibiotics and metals, also unveil the hidden environmental effects of combined pollution.202336375951
6830160.9997Heavy metal could drive co-selection of antibiotic resistance in terrestrial subsurface soils. Terrestrial surface ecosystems are important sinks for antibiotic resistance genes (ARGs) due to the continuous discharge of contaminants from human-impacted ecosystems. However, the abundance and resistance types of ARGs and their influencing factors in terrestrial subsurface soils are not well known. In this study, we investigated the abundance and diversity of ARGs, and their correlations with metal resistance genes (MRGs), mobile genetic elements (MGEs), bacteria, and heavy metals in subsurface soils using high throughput quantitative PCR and metagenomic sequencing approaches. Abundant and diverse ARGs were detected with high spatial heterogeneity among sampling sites. Vertically, there was no significant difference in ARG profiles between the aquifer and non-aquifer soils. Heavy metals were key factors shaping ARG profiles in soils with high heavy metal contents, while they showed no significant effect in low contents. Moreover, heavy metals could trigger the proliferation of antibiotic resistance by increasing MGE abundance or influencing bacterial communities. Metagenomic analysis also revealed the widespread co-occurrence of ARGs and MRGs, with heavy metals possibly enhancing the co-selection of ARGs and MRGs in soils with high heavy metal contents. This study highlighted the heavy metal-driven co-selection of ARGs and revealed the occurrence of ARG pollution in terrestrial subsurface soils.202133858075
6901170.9997Polycyclic aromatic hydrocarbons (PAHs) enriching antibiotic resistance genes (ARGs) in the soils. The prevalence of antibiotic resistance genes (ARGs) in modern environment raises an emerging global health concern. In this study, soil samples were collected from three sites in petrochemical plant that represented different pollution levels of polycyclic aromatic hydrocarbons (PAHs). Metagenomic profiling of these soils demonstrated that ARGs in the PAHs-contaminated soils were approximately 15 times more abundant than those in the less-contaminated ones, with Proteobacterial being the preponderant phylum. Resistance profile of ARGs in the PAHs-polluted soils was characterized by the dominance of efflux pump-encoding ARGs associated with aromatic antibiotics (e.g., fluoroquinolones and acriflavine) that accounted for more than 70% of the total ARGs, which was significantly different from representative sources of ARG pollution due to wide use of antibiotics. Most of ARGs enriched in the PAHs-contaminated soils were not carried by plasmids, indicating the low possibilities of them being transferred between bacteria. Significant correlation was observed between the total abundance of ARGs and that of Proteobacteria in the soils. Proteobacteria selected by PAHs led to simultaneously enriching of ARGs carried by them in the soils. Our results suggested that PAHs could serve as one of selective stresses for greatly enriching of ARGs in the human-impacted environment.201727876418
6898180.9997Co-selection and stability of bacterial antibiotic resistance by arsenic pollution accidents in source water. Frequent heavy-metal pollution accidents severely deteriorated the source water quality of drinking water treatment plants (DWTP). Limited data have explicitly addressed the impact of these incidents on bacterial antibiotic resistance (BAR). In present study, we investigated the shift of antibiotic resistome caused by heavy metal pollution incidents via simulating an arsenic shock loading [As (III)], along with the associated risks imposed on drinking water systems. The results indicated that a quick co-selection of antibiotic resistant bacteria (ARB) was achieved after exposure to 0.2-1 mg/L As (III) for only 6 h, meanwhile, there was an increase of relative abundance of antibiotic resistance genes (ARGs) and mobile genetic elements. Most of the co-selected BAR could be maintained for at least 4 days in the absence of As (III) and antibiotics, implying that the pollution in source water possibly contributed to the preservation and proliferation of antibiotic resistance determinants in the subsequent DWTP. Bacterial community structure analysis showed a strong correlation between bacterial community shift and BAR promotion, and enrichment of opportunistic bacteria (e.g. Escherichia-Shigella, Empedobacter sp. and Elizabethkingia sp.). The results indicated a potential epidemiological threat to the public due to accident-level arsenic contamination in the source water. This study gave insight into understanding the source water pollution accidents from the perspective of bio-hazard and biological risks, and highlighted a neglected important source of BAR in drinking water systems.202031794937
6948190.9997Fate of antibiotic resistance genes and metal resistance genes during the thermophilic fermentation of solid and liquid swine manures in an ectopic fermentation system. Environmental pollution due to resistance genes from livestock manure has become a serious issue that needs to be resolved. However, little studies focused on the removal of resistance genes in simultaneous processing of livestock feces and urine. This study investigated the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and class 1 integron-integrase gene (intI1) during thermophilic fermentation of swine manure in an ectopic fermentation system (EFS), which has been regarded as a novel system for efficiently treating both feces and urine. The abundances of MRGs and tetracycline resistance genes were 34.44-97.71% lower in the EFS. The supplementation of heavy metals significantly increased the abundance of intI1, with the enhancement effect of copper being more prominent than that of zinc. The highest abundances of resistance genes and intI1 were observed at high Cu levels (A2), indicating that Cu can increase the spreading of resistance genes through integrons. Network analysis revealed the co-occurrence of ARGs, MRGs, and intI1, and these genes potentially shared the same host bacteria. Redundancy analysis showed that the bacterial community explained most of the variations in ARGs, and environmental factors had influences on ARGs abundances by modulating the bacterial community composition. The decreased Sphingomonas, Comamonas, Acinetobacter, Lactobacillus, Bartonella, Rhizobium, and Bacteroides were mainly responsible for the reduced resistance genes. These results demonstrate that EFS can reduce resistance genes in simultaneous processing of livestock feces and urine.202133592372