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762100.9978Pre-chlorination in source water endows ARB with resistance to chlorine disinfection in drinking water treatment. Chlorine disinfection is widely used to ensure biosafety of drinking water. However, antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are often detected in treated drinking water. The impact of chlorine disinfection on the abundance of ARGs in drinking water is currently contradictory. Some studies suggested that chlorine disinfection could reduce the abundance of ARGs, while others had found that chlorine disinfection increased the abundance of ARGs. Pre-chlorination is widely applied in raw water to kill the algae cells in source water Pump Station. Different distances between the source water Pump Station and the drinking water treatment plants (DWTPs) resulted in different degrees of residual chlorine decay in the incoming raw water. This study found that the abundance of ARGs in drinking water would be increased during chlorine disinfection when the chlorine concentration in raw water was higher (> 0.2 mg/L). On the contrary, chlorine disinfection would decrease the abundance of ARGs in drinking water when the chlorine concentration in raw water was lower (< 0.09 mg/L). Pre-chlorination in source water with sub-lethal concentration could allow ARB to adapt to the chlorine environment in advance, endowing ARB with chlorine resistance, which resulted in ineffective removal of ARB and increased ARGs abundance during subsequent chlorine disinfection. High abundance of chlorine and antibiotics co-resistance bacteria in raw water was the main reason for the increase in ARGs abundance in chlorine treated drinking water. It should be noticed that, pre-chlorination treatment in source water would increase the difficulty of removing ARGs in subsequent chlorine disinfection process.202540398032
858010.9977Mitigation of microplastic-associated emerging pollutants by chlorination using field-collected microplastic: Antimicrobial-resistant genes and pathogens. The ubiquity of microplastics (MPs) in aquatic environments has raised significant concerns regarding their roles as vectors for antibiotic-resistance genes (ARGs) and antibiotic-resistant pathogens (ARPs). This study investigated the mitigation of ARGs and ARPs associated with field-collected MPs through chlorination using free available chlorine (FAC) at varying concentrations. FAC effectively reduced the absolute abundance of ARGs on MPs by up to 99.69 %, although the relative abundance of certain ARGs persisted or increased after treatments. Results revealed that the three-dimensional structure of biofilms on MPs significantly influenced FAC efficacy, with interior biofilm bacteria demonstrating greater resistance than outer biofilm. Additionally, FAC induced fragmentation of MPs, particularly increasing the proportion of particles smaller than 100 μm. Notably, ARGs such as sul1 and ermB showed substantial reductions in absolute abundance, whereas ermC and sul2 exhibited less reduction, highlighting the complexity of disinfection in MP-associated biofilms. These findings underscore the need for optimizing disinfection strategies to mitigate ARG dissemination and address environmental risks posed by MPs in wastewater effluents.202540436100
639420.9976Potential Environmental and Human Health Risks Caused by Antibiotic-Resistant Bacteria (ARB), Antibiotic Resistance Genes (ARGs) and Emerging Contaminants (ECs) from Municipal Solid Waste (MSW) Landfill. The disposal of municipal solid waste (MSW) directly at landfills or open dump areas, without segregation and treatment, is a significant concern due to its hazardous contents of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and metal resistance genes (MGEs). The released leachate from landfills greatly effects the soil physicochemical, biological, and groundwater properties associated with agricultural activity and human health. The abundance of ARB, ARGs, and MGEs have been reported worldwide, including MSW landfill sites, animal husbandry, wastewater, groundwater, soil, and aerosol. This review elucidates the occurrence and abundance of ARB, ARGs, and MRGs, which are regarded as emerging contaminants (ECs). Recently, ECs have received global attention because of their prevalence in leachate as a substantial threat to environmental and public health, including an economic burden for developing nations. The present review exclusively discusses the demands to develop a novel eco-friendly management strategy to combat these global issues. This review also gives an intrinsic discussion about the insights of different aspects of environmental and public health concerns caused due to massive leachate generation, the abundance of antibiotics resistance (AR), and the effects of released leachate on the various environmental reservoirs and human health. Furthermore, the current review throws light on the source and fate of different ECs of landfill leachate and their possible impact on the nearby environments (groundwater, surface water, and soil) affecting human health. The present review strongly suggests the demand for future research focuses on the advancement of the removal efficiency of contaminants with the improvement of relevant landfill management to reduce the potential effects of disposable waste. We propose the necessity of the identification and monitoring of potential environmental and human health risks associated with landfill leachate contaminants.202133915892
639530.9976Risk control of antibiotics, antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) during sewage sludge treatment and disposal: A review. Sewage sludge is an important reservoir of antibiotics, antibiotic resistance genes (ARGs), and antibiotic resistant bacteria (ARB) in wastewater treatment plants (WWTPs), and the reclamation of sewage sludge potentially threats human health and environmental safety. Sludge treatment and disposal are expected to control these risks, and this review summarizes the fate and controlling efficiency of antibiotics, ARGs, and ARB in sludge involved in different processes, i.e., disintegration, anaerobic digestion, aerobic composting, drying, pyrolysis, constructed wetland, and land application. Additionally, the analysis and characterization methods of antibiotics, ARGs, and ARB in complicate sludge are reviewed, and the quantitative risk assessment approaches involved in land application are comprehensively discussed. This review benefits process optimization of sludge treatment and disposal, with regard to environmental risks control of antibiotics, ARGs, and ARB in sludge. Furthermore, current research limitations and gaps, e.g., the antibiotic resistance risk assessment in sludge-amended soil, are proposed to advance the future studies.202336933744
792840.9976Insight into the responses of antibiotic resistance genes in microplastic biofilms to zinc oxide nanoparticles and zinc ions pressures in landfill leachate. Microplastic (MP) biofilms are hotspots of antibiotic resistance genes (ARGs) in landfill environment. MP biofilms in landfill leachate coexist with heavy metals and metallic nanoparticles (NPs) that considered to be the selective agents of ARGs. However, the effects of these selective pressures on ARGs in MP biofilms and their differences in MP-surrounding leachate have not been well understood. Herein, the changes of ARG abundances in MP biofilms and corresponding leachate under zinc oxide (ZnO) NPs and zinc ion (Zn(2+)) pressures were comparatively analyzed. The presence of ZnO NPs and Zn(2+) promoted the enrichment of ARGs in MP biofilms, and the enrichment was more pronounced in ZnO NPs groups. ZnO NPs and especially Zn(2+) mainly decreased the abundances of ARGs in leachate. The increase of integron abundances and reactive oxygen species production in MP biofilms implied the enhanced potential for horizontal transfer of ARGs under ZnO NPs and Zn(2+) pressures. Meanwhile, the co-occurrence pattern between ARGs and bacterial genera in MP biofilms with more diverse potential ARG hosts was more complex than in leachate, and the enrichment of ARG-hosting bacteria in MP biofilms under ZnO NPs and Zn(2+) pressures supported the enrichment of ARGs.202337480611
854650.9975A review of emerging organic contaminants (EOCs), antibiotic resistant bacteria (ARB), and antibiotic resistance genes (ARGs) in the environment: Increasing removal with wetlands and reducing environmental impacts. Emerging organic contaminants (EOCs) include a diverse group of chemical compounds, such as pharmaceuticals and personal care products (PPCPs), pesticides, hormones, surfactants, flame retardants and plasticizers. Many of these compounds are not significantly removed in conventional wastewater treatment plants and are discharged to the environment, presenting an increasing threat to both humans and natural ecosystems. Recently, antibiotics have received considerable attention due to growing microbial antibiotic-resistance in the environment. Constructed wetlands (CWs) have proven effective in removing many EOCs, including different antibiotics, before discharge of treated wastewater into the environment. Wastewater treatment systems that couple conventional treatment plants with constructed and natural wetlands offer a strategy to remove EOCs and reduce antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) far more efficiently than conventional treatment alone. This review presents as overview of the current knowledge on the efficiency of different wetland systems in reducing EOCs and antibiotic resistance.202032247686
682060.9975Microcosm experiments deciphered resistome coalescence, risks and source-sink relationship of antibiotic resistance in the soil irrigated with reclaimed water. Reclaimed water is widely used in agriculture irrigation to alleviate water scarcity, whereas the dissemination of antibiotic resistance genes (ARGs) in the soil it introduces has attracted widespread attention. Currently, few studies have systematically elucidated the coalescence of the resistome originating from reclaimed water with the soil's native community. Also, the effects and mechanisms of irrigation on the dissemination of ARGs in soils have yet to be demonstrated. To address this gap, microcosm experiments have been conducted in this study to decipher the resistome coalescence, risks and source-sink relationship of ARGs in soils irrigated with reclaimed water. The results show 237 ARGs, 55 mobile genetic elements (MGEs) and 28 virulence factors were identified in the irrigated soils. Irrigation increased the abundance and diversity of ARGs in the soil by introducing antibiotic-resistant bacteria, altering the microbial community and facilitating horizontal transfer of ARGs via MGEs, and ultimately exacerbated resistome risks in the environment. Relatively, a larger volume of irrigation water led to a more complex propagation network of the resistome. Source apportionment analysis suggested reclaimed water contributed less than 15 % of ARGs in the irrigated soils, whereas its contribution proportion increased with a larger volume of irrigation water.202539874760
812370.9975The effect of bulk-biochar and nano-biochar amendment on the removal of antibiotic resistance genes in microplastic contaminated soil. Biochar amendment has significant benefits in removing antibiotic resistance genes (ARGs) in the soil. Nevertheless, there is little information on ARGs removal in microplastic contaminated soil. Herein, a 42-day soil microcosm experiment were carried out to study how two coconut shell biochars (bulk- and nano-size) eliminate soil ARGs with/without microplastic presence. The results showed that microplastic increased significantly the numbers and abundances of ARGs in soil at 14d of cultivation. And, two biochars amendment effectively inhibited soil ARGs spread whether or not microplastic was present, especially for nano-biochar which had more effective removal compared to bulk-biochar. However, microplastic weakened soil ARGs removal after applying same biochar. Two biochars removed ARGs through decreasing horizontal gene transfer (HGT) of ARGs, potential host-bacteria abundances, some bacteria crowding the eco-niche of hosts and promoting soil properties. The adverse effect of microplastic on ARGs removal was mainly caused by weakening mobile genetic elements (MGEs) removal, and by changing soil properties. Structural equation modeling (SEM) analysis indicated that biochar's effect on ARGs profile was changed by its size and microplastic presence through altering MGEs abundances. These results highlight that biochar amendment is still an effective method for ARGs removal in microplastic contaminated soil.202437907163
692680.9975Insights into the driving factors of vertical distribution of antibiotic resistance genes in long-term fertilized soils. The prevalence of antibiotic resistance genes (ARGs) in soils has aroused wide attention. However, the influence of long-term fertilization on the distribution of ARGs in different soil layers and its dominant drivers remain largely unknown. In this study, a total of 203 ARGs were analyzed in greenhouse vegetable soils (0-100 cm from a 13-year field experiment applied with different fertilizers (control, chemical fertilizer, organic manure, and mixed fertilizer). Compared with unfertilized and chemically fertilized soils, manure application significantly increased the abundance and alpha diversity of soil ARGs, where the assembly of ARG communities was strongly driven by stochastic processes. The distribution of ARGs was significantly driven by manure application within 60 cm, while it was insignificantly changed in soil below 60 cm under different fertilization regimes. The inter-correlations of ARGs with mobile genetic elements (MGEs) and microbiota were strengthened in manured soil, indicating manure application posed a higher risk for ARGs diffusion in subsurface soil. Bacteria abundance and MGEs directly influenced ARG abundance and composition, whereas soil depth and manure application indirectly influenced ARG abundance and composition by affecting antibiotics. These results strengthen our understanding of the long-term anthropogenic influence on the vertical distribution of soil ARGs and highlight the ecological risk of ARGs in subsurface soil induced by long-term manure application.202337247491
854990.9974Current perspectives on microalgae and extracellular polymers for reducing antibiotic resistance genes in livestock wastewater. Antibiotic resistance genes (ARGs) in livestock wastewater resulting from excessive antibiotics used in animal farming pose significant environmental and public health risks. Conventional treatment methods are often costly, inefficient, and may inadvertently promote ARG transmission. Microalgae, with their long genetic distance from bacteria and strong ability to utilize wastewater nutrients, offer a sustainable solution for ARG mitigation. This review studied the abundance and characterization of ARGs in livestock wastewater, highlighted microalgal-based removal mechanisms of ARGs, including phagocytosis, competition, and absorption by extracellular polymeric substances (EPS), and explored factors influencing their efficacy. Notably, the microalgae-EPS system reduced ARGs by 0.62-3.00 log, demonstrating significant potential in wastewater treatment. Key challenges, such as optimizing algal species, understanding EPS-ARG interactions, targeted reduction of host bacteria, and scaling technologies, were discussed. This work provides critical insights for advancing microalgal-based strategies for ARG removal, promoting environmentally friendly and efficient wastewater management.202540324729
6474100.9974Impact of treated wastewater irrigation on antibiotic resistance in the soil microbiome. The reuse of treated wastewater (TWW) for irrigation is a practical solution for overcoming water scarcity, especially in arid and semiarid regions of the world. However, there are several potential environmental and health-related risks associated with this practice. One such risk stems from the fact that TWW irrigation may increase antibiotic resistance (AR) levels in soil bacteria, potentially contributing to the global propagation of clinical AR. Wastewater treatment plant (WWTP) effluents have been recognized as significant environmental AR reservoirs due to selective pressure generated by antibiotics and other compounds that are frequently detected in effluents. This review summarizes a myriad of recent studies that have assessed the impact of anthropogenic practices on AR in environmental bacterial communities, with specific emphasis on elucidating the potential effects of TWW irrigation on AR in the soil microbiome. Based on the current state of the art, we conclude that contradictory to freshwater environments where WWTP effluent influx tends to expand antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes levels, TWW irrigation does not seem to impact AR levels in the soil microbiome. Although this conclusion is a cause for cautious optimism regarding the future implementation of TWW irrigation, we conclude that further studies aimed at assessing the scope of horizontal gene transfer between effluent-associated ARB and soil bacteria need to be further conducted before ruling out the possible contribution of TWW irrigation to antibiotic-resistant reservoirs in irrigated soils.201323378260
8581110.9974Tire particles and its leachates: Impact on antibiotic resistance genes in coastal sediments. Tire particles (TPs), a significant group of microplastics, can be discharged into the coastal environments in various ways. However, our understanding of how TPs impact the antibiotic resistance and pathogenic risks of microorganisms in coastal sediments remains limited. In this study, we used metagenomics to investigate how TPs and their leachates could affect the prevalence of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and their potential risks to the living creatures such as soil invertebrates and microorganisms in the coastal sediments. We discovered that TP addition significantly increased the abundance and diversity of ARGs and VFGs in coastal sediments, with raw TPs displayed higher impacts than TP leachates and TPs after leaching on ARGs and VFGs. With increasing TP exposure concentrations, the co-occurrence frequency of ARGs and mobile genetic elements (MGEs) in the same contig also increased, suggesting that TPs could enhance the dispersal risk of ARGs. Our metagenome-based binning analysis further revealed that exposure to TPs increased the abundance of potentially pathogenic antibiotic-resistant bacteria (PARB). In addition, chemical additives of TP leachates (e.g., Zn and N-cyclohexylformamide) significantly affected the changes of ARGs in the pore water. In summary, our study provides novel insights into the adverse effects of TP pollutions on aggravating the dissemination and pathogenic risks of ARGs and PARB in the coastal environment.202438147751
6930120.9974Effect of fertilizer type on antibiotic resistance genes by reshaping the bacterial community and soil properties. Conventional and bio-organic fertilizers play an important role in maintaining soil health and promoting crop growth. However, the effect of organic fertilizers on the prevalence of antibiotic resistance genes (ARGs) in the vegetable cropping system has been largely overlooked. In this study, we investigated the impacts of soil properties and biotic factors on ARG profiles by analyzing ARG and bacterial communities in vegetable copping soils with a long-term history of manure and bio-organic fertilizer application. The ARG abundance in the soil was significantly increased by 116% with manure application compared to synthetic NPK fertilizer application. This finding was corroborated by our meta-analysis that the longer the duration of manure application, the greater the response of increased soil ARG abundance. However, bio-organic fertilizers containing Trichoderma spp. Significantly reduced ARG contamination by 31% compared to manure application. About half of the ARG variation was explained by changes in bacterial abundance and structure, followed by soil properties. The mitigation of ARG by Trichoderma spp. Is achieved by altering the structure of the bacterial community and weakening the close association between bacteria and ARG prevalence. Taken together, these findings shed light on the contribution of bio-organic fertilizers in mitigating ARG contamination in agricultural soils, which can help manage the ecological risk posed by ARG inputs associated with manure application.202337343633
7576130.9974Spatial behavior and source tracking of extracellular antibiotic resistance genes in a chlorinated drinking water distribution system. Antibiotic resistance genes (ARGs) are receiving increasing concerns due to the antibiotic resistance crisis. Nevertheless, little is known about the spatial behavior and sources of extracellular ARGs (eARGs) in the chlorinated drinking water distribution systems (DWDSs). Here, tap water was continuously collected to reveal the occurrence of both eARGs and intracellular ARGs (iARGs) along a chlorinated DWDS. Afterward, the correlation between eARGs, eDNA-releasing communities, and communities of planktonic bacteria was further analyzed. The eARG concentration decreased significantly, whereas the proportion of vanA and bla(NDM-1) increased. Further, the diversity of the eDNA-releasing community increased markedly with increasing distance from the drinking water treatment plant (DWTP). Moreover, the dominant eDNA-releasing bacteria shifted from Acinetobacter, Pseudomonas, and Methylobacterium-Methylorubrum in finished water from the DWTP to Bacteroides, Faecalibacterium, Staphylococcus, and Parabacteroides in the DWDS. In terms of eARG source, thirty genera were significantly correlated with seven types of eARGs that resulted from the lysis of dead planktonic bacteria and detached biofilms. Conversely, the iARGs concentration increased, whereas the biodiversity of the planktonic bacteria community decreased in the sampling points along the DWDSs. Our findings provide critical insights into the spatial behavior and sources of eARGs, highlighting the health risks associated with ARGs in DWDSs.202234902725
7930140.9974Fates of extracellular and intracellular antibiotic resistance genes in activated sludge and plastisphere under sulfadiazine pressure. Microplastics, antibiotics, and antibiotic resistance genes (ARGs) represent prominent emerging contaminants that can potentially hinder the efficacy of biological wastewater treatment and pose health risks. Plastisphere as a distinct ecological niche for microorganisms, acts as a repository for ARGs and potential pathogenic bacteria. Nonetheless, the spread pattern of extracellular ARGs (eARGs) and intracellular ARGs (iARGs) in plastisphere under antibiotic exposure was not yet known. This study aimed to investigate disparities in extracellular polymeric substances (EPS) production, extracellular and intracellular microbial community structures, as well as the transmission of eARGs and iARGs between activated sludge and plastisphere in an anaerobic/anoxic/oxic system under sulfadiazine (SDZ) exposure. SDZ was found to enhance EPS production in activated sludge and plastisphere. Interestingly, as SDZ removal efficiency increased, EPS content decreased in activated sludge and plastisphere collected from oxic zone, and continued to increase in plastisphere samples collected from anaerobic and anoxic zones. There were significant differences in microbial community structure between activated sludge and plastisphere, and the DNA fragments of potential pathogenic bacteria were detected in extracellular samples. SDZ exhibited a promoting effect on the propagation of eARGs, which were more abundant in the plastisphere than in activated sludge, thus heightening the risk of ARGs dissemination. Extracellular mobile genetic elements played a pivotal role in driving the spread of eARGs, while the microbial community induced the changes of iARGs. Potential pathogenic bacteria emerged as potential hosts for ARGs and mobile genetic elements within activated sludge and plastisphere, leading to more serious environmental threats.202337898001
7620150.9974Higher chlorine dosage does not consistently enhance antibiotic resistance mitigation in the Cl(2)-UV process. Health problems arising from antibiotic resistance are a global concern. The Cl(2)-UV disinfection process has shown potential for controlling antibiotic resistance in water; however, the influence of disinfectant dosage on its effectiveness remains insufficiently understood. Can antibiotic resistance be controlled by simply increasing the disinfectant dosage? This study demonstrated that higher disinfectant levels improved antibiotic resistance gene (ARG) removal, with certain ARGs reaching 1.82 log removal under conventional conditions. Nevertheless, higher disinfectant dosages also led to an increase in the relative abundance of multidrug resistance genes (MRGs), aminoglycoside resistance genes (AmRGs), and fosmidomycin resistance genes (FRGs). Correlation analysis of ARGs with mobile genetic elements (MGEs) and ARG-host bacteria indicated that this enrichment was primarily driven by enhanced horizontal gene transfer (HGT). Notably, increases in UV fluence and chlorine dose had distinct impacts on the total relative abundance of ARGs: higher UV fluence reduced total relative abundance, whereas higher chlorine dose increased it. These contrasting trends are likely linked to differences in the dominant HGT pathways under each condition. Greater UV fluence tended to promote conjugative transfer among surviving bacteria, while higher chlorine dosages more effectively facilitated natural transformation. Considering both the absolute and relative abundances of ARGs, along with calculated health-risk indices for each treatment condition, the findings indicated that increasing UV fluence is more effective for controlling ARGs in water. These results provide valuable insights for optimizing the Cl(2)-UV disinfection process to better manage antibiotic resistance in aquatic environments.202540914041
6953160.9974Long-term biogas slurry application increased antibiotics accumulation and antibiotic resistance genes (ARGs) spread in agricultural soils with different properties. Animal manures are commonly applied to soil which possibly promote the spread of antibiotic resistance from soil to human beings via food chains. Biogas slurry is an end product of anaerobic digestion of animal manures, which has been widely applied as fertilizers in the agricultural soil. However, effect of long-term biogas slurry application on the soil antibiotic resistance and the associated mechanism still remains unclear. The present study characterized antibiotics, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial community, in different agricultural soils unamended (BS-) and amended (BS+) with biogas slurry (8-18 years) in five field experiments. Our results indicated that long-term application of biogas slurry largely increased the concentrations of tetracyclines in soils, and greatly increased the abundances of ARGs, transposase gene (Tn916/1545) and ARGs-associated bacteria. Long-term application of biogas slurry led to tetracyclines accumulation and ARGs enrichment in agricultural soil, and the selection pressure from tetracyclines and the increase of Tn916/1545 abundace become potential contributors for the increase of soil antibiotic resistance via promoting the enrichment of ARG-associated bacteria. The results of the present study should be taken into consideration to develop policy and practice for mitigating the enrichment and spread of antibiotic resistance during the recycling of biogas slurry into agricultural soil.202133203566
7556170.9974The fate and behavior mechanism of antibiotic resistance genes and microbial communities in anaerobic reactors treating oxytetracycline manufacturing wastewater. In this study, two parallel-operated expanded granular sludge bed (EGSB) reactors, one used to treat oxytetracycline (OTC) manufacturing wastewater with gradual increase of OTC concentration as experimental reactor and the other fed with the same wastewater without OTC as control reactor, were operated to investigate the behavior of antibiotics resistance genes (ARGs) and mobile genetic elements (MGEs) and their possible relationships with bacterial community among influent, sludge and effluent environments. Though the average absolute abundance of ARGs slightly decreased (0.26 - log), the ARGs' relative abundance normalized to 16S-rRNA gene copy numbers showed a significant upward trend in effluent (2 multiples - increase) and the absolute and relative abundances both extremely increased in anaerobic sludge, indicating that anaerobic treatment process cannot reduce ARGs efficiently, inversely can increase the risk of ARGs through the proliferation of antibiotics resistance bacteria (ARB) under the suppression of OTC. MGEs, bacterial communities and OTC concentration mainly impacted the ARGs profiles, which contributed 88.4% to the variation of ARGs. The differences and correlations of hosts in influent, effluent and sludge were further confirmed by network analysis. Overall, this study enhanced the understanding of the prevalence and transfer of ARGs in OTC production effluents during anaerobic treatment.202234740157
7020180.9973Microbiome, resistome and mobilome of chlorine-free drinking water treatment systems. Drinking water treatment plants (DWTPs) are designed to remove physical, chemical, and biological contaminants. However, until recently, the role of DWTPs in minimizing the cycling of antibiotic resistance determinants has got limited attention. In particular, the risk of selecting antibiotic-resistant bacteria (ARB) is largely overlooked in chlorine-free DWTPs where biological processes are applied. Here, we combined high-throughput quantitative PCR and metagenomics to analyze the abundance and dynamics of microbial communities, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs) across the treatment trains of two chlorine-free DWTPs involving dune-based and reservoir-based systems. The microbial diversity of the water increased after all biological unit operations, namely rapid and slow sand filtration (SSF), and granular activated carbon filtration. Both DWTPs reduced the concentration of ARGs and MGEs in the water by circa 2.5 log gene copies mL(-1), despite their relative increase in the disinfection sub-units (SSF in dune-based and UV treatment in reservoir-based DWTPs). The total microbial concentration was also reduced (2.5 log units), and none of the DWTPs enriched for bacteria containing genes linked to antibiotic resistance. Our findings highlight the effectiveness of chlorine-free DWTPs in supplying safe drinking water while reducing the concentration of antibiotic resistance determinants. To the best of our knowledge, this is the first study that monitors the presence and dynamics of antibiotic resistance determinants in chlorine-free DWTPs.202336989799
7000190.9973Animal manures application increases the abundances of antibiotic resistance genes in soil-lettuce system associated with shared bacterial distributions. An increasing amount of animal manures is being used in agriculture, and the effect of animal manures application on the abundance of antibiotics resistance genes (ARGs) in soil-plant system has attracted widespread attention. However, the impacts of animal manures application on the various types of bacterial distribution that occur in soil-lettuce system are unclear. To address this topic, the effects of poultry manure, swine manure or chemical fertilizer application on ARG abundance and the distribution of shared bacteria were investigated in this study. In a lettuce pot experiment, 13 ARGs and 2 MGEs were quantified by qPCR, and bacterial communities in the soil, lettuce endosphere and lettuce phyllosphere were analysed by 16S rRNA sequence analysis. The results showed that the application of poultry or swine manure significantly increased ARG abundance in the soil, a result attributed mainly to increases in the abundances of tetG and tetC. The application of poultry manure, swine manure and chemical fertilizer significantly increased ARG abundance in the lettuce endosphere, and tetG abundance was significantly increased in the poultry and swine manure groups. However, animal manures application did not significantly increase ARG abundance in the lettuce phyllosphere. Flavobacteriaceae, Sphingomonadaceae and 11 other bacterial families were the shared bacteria in the soil, lettuce endosphere, and phyllosphere. The Streptomycetaceae and Methylobacteriaceae were significantly positively correlated with intI1 in both the soil and endosphere. Chemical fertilizer application increased both the proportions of Sphingomonadaceae and tetX abundance, which were positively correlated in the endosphere. Comamonadaceae and Flavobacteriaceae were not detected in the lettuce endosphere under swine manure application. Cu was related to Flavobacteriaceae in the lettuce endosphere. Overall, poultry and swine manure application significantly increased ARG abundance in the soil-lettuce system, which might be due to the shared bacterial distribution.202134004530