Effects of heavy metals on the development and proliferation of antibiotic resistance in urban sewage treatment plants. - Related Documents




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746601.0000Effects 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
746510.9999Effects of co-selection of antibiotic-resistance and metal-resistance genes on antibiotic-resistance potency of environmental bacteria and related ecological risk factors. The inadequate elimination of micropollutants in wastewater treatment plants (WWTP), cause to increase in the incidence of antibiotic resistant bacterial strains. Growth of microbial pathogens in WWTP is one of the serious public health problems. The widespread and simultaneous emergence of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) in the environment with heavy metals create persistent and selective pressure for co-selection of both genes on environmental microorganisms. Co-localization of ARGs and HMRGs on the same horizontal mobile genetic elements (MGEs) allows the spreading of numerous antibiotic-resistant strains of bacteria in aquatic and terrestrial environment. The biofilm formation and colonization potential of environmental bacteria leads to the co-selection of multi-antibiotic resistance and multi-metal tolerance. Horizontal gene transfer (HGT), co-localization of both ARGs and HMRGs on the same MGEs, and the shared resistomes are important bacteria-associated ecological risks factors, which reduce the effectiveness of antibiotics against bacterial infections.202336805463
739120.9999Antibiotic resistance genes in China: occurrence, risk, and correlation among different parameters. Antibiotic resistance has become a widely concerned issue due to the huge risk on the ecological environment and human health. China has the highest production and consumption of antibiotics than other countries. Thus, antibiotic resistance genes (ARGs) have been detected in various environmental settings (e.g., surface water, wastewater, sediment) in China. The occurrence of ARGs in these matrixes was summarized and discussed in this review. Sulfonamide resistance genes and tetracycline resistance genes were the most frequently detected ARGs in China. According to the abundance of these two classes of ARGs in the natural environment, sulfonamide resistance genes seem to be more stable than tetracycline resistance genes. Furthermore, the relationships between ARGs and antibiotics, antibiotic resistance bacteria (ARB), heavy metals, and environmental parameters (e.g., pH, organics) were also investigated. Specifically, relative abundance of total ARGs was found to correlate well with concentration of total antibiotics in aqueous phase but not in the solid phase (soil, sediment, sludge, and manure). As for relationship between ARGs and ARB, metals, and environmental parameters in different media, due to complex and variable environment, some exhibit positive correlation, some negative, while others no correlation at all. Three potential risks are discussed in the text: transmission to human, synergistic effect of different ARGs, and variability of ARGs. However, due to the complexity of the environment, more work is needed to establish a quantitative approach of ARG risk assessment, which can provide a theoretical support for the management of antibiotics and the protection of human health.201829948704
742930.9999Industrial wastewater treatment plant enriches antibiotic resistance genes and alters the structure of microbial communities. Antibiotic resistance is an emerging global health crisis, driven largely by overuse and misuse of antibiotics. However, there are examples in which the production of these antimicrobial agents has polluted the environment with active antibiotic residues, selecting for antibiotic resistant bacteria and the genes they carry. In this work, we have used shotgun metagenomics to investigate the taxonomic structure and resistance gene composition of sludge communities in a treatment plant in Croatia receiving wastewater from production of the macrolide antibiotic azithromycin. We found that the total abundance of antibiotic resistance genes was three times higher in sludge from the treatment plant receiving wastewater from pharmaceutical production than in municipal sludge from a sewage treatment plant in Zagreb. Surprisingly, macrolide resistance genes did not have higher abundances in the industrial sludge, but genes associated with mobile genetic elements such as integrons had. We conclude that at high concentrations of antibiotics, selection may favor taxonomic shifts towards intrinsically resistant species or strains harboring chromosomal resistance mutations rather than acquisition of mobile resistance determinants. Our results underscore the need for regulatory action also within Europe to avoid release of antibiotics into the environment.201931301473
734240.9999Metagenomic analysis reveals the prevalence and persistence of antibiotic- and heavy metal-resistance genes in wastewater treatment plant. The increased antibiotic resistance among microorganisms has resulted into growing interest for investigating the wastewater treatment plants (WWTPs) as they are reported to be the major source in the dissemination of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) in the environment. In this study, we investigated the prevalence and persistence of ARGs and HMRGs as well as bacterial diversity and mobile genetic elements (MGEs) in influent and effluent at the WWTP in Gwangju, South Korea, using high-throughput sequencing based metagenomic approach. A good number of broad-spectrum of resistance genes (both ARG and HMRG) were prevalent and likely persistent, although large portion of them were successfully removed at the wastewater treatment process. The relative abundance of ARGs and MGEs was higher in effluent as compared to that of influent. Our results suggest that the resistance genes with high abundance and bacteria harbouring ARGs and MGEs are likely to persist more through the treatment process. On analyzing the microbial community, the phylum Proteobacteria, especially potentially pathogenic species belonging to the genus Acinetobacter, dominated in WWTP. Overall, our study demonstrates that many ARGs and HMRGs may persist the treatment processes in WWTPs and their association to MGEs may contribute to the dissemination of resistance genes among microorganisms in the environment.201829858829
751450.9999Early and differential bacterial colonization on microplastics deployed into the effluents of wastewater treatment plants. Microbial colonization of microplastics (MPs) in aquatic ecosystems is a well-known phenomenon; however, there is insufficient knowledge of the early colonization phase. Wastewater treatment plant (WWTP) effluents have been proposed as important pathways for MPs entry and transport in aquatic environments and are hotspots of bacterial pathogens and antibiotic resistance genes (ARGs). This study aimed at characterizing bacterial communities in the early stage of biofilm formation on seven different types of MPs deployed in two different WWTPs effluents as well as measuring the relative abundance of two ARGs (sulI and tetM) on the tested MPs. Illumina Miseq sequencing of the 16S rRNA showed significant higher diversity of bacteria on MPs in comparison with free-living bacteria in the WWTP effluents. β-diversity analysis showed that the in situ environment (sampling site) and hydrophobicity, to a lesser extent, had a role in the early bacterial colonization phase. An early colonization phase MPs-core microbiome could be identified. Furthermore, specific core microbiomes for each type of polymer suggested that each type might select early attachment of bacteria. Although the tested WWTP effluent waters contained antibiotic resistant bacteria (ARBs) harboring the sulI and tetM ARGs, MPs concentrated ARBs harboring the sulI gene but not tetM. These results highlight the relevance of the early attachment phase in the development of bacterial biofilms on different types of MP polymers and the role that different types of polymers might have facilitating the attachment of specific bacteria, some of which might carry ARGs.202133246729
747160.9999Impact 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
746870.9999Enrofloxacin-induced transfer of multiple-antibiotic resistance genes and emergence of novel resistant bacteria in red swamp crayfish guts and pond sediments. Antibiotic resistance genes (ARGs) can be transferred from environmental microbes to human pathogens, thus leading to bacterial infection treatment failures. The aquaculture polluted by over-used antibiotics is considered as a notorious reservoir of ARGs. However, the origin, diachronic changes, and mobility of ARGs under antibiotic exposure in aquaculture systems remain elusive. Our findings showed that enrofloxacin application also increased the relative abundance of various ARGs in addition to quinolone-resistance genes and induced ARG dissemination in crayfish gut and sediment bacteria. Further investigation indicated that the transposase-mediated recombination was the major driver of horizontal gene transfer (HGT) of ARGs under antibiotic stress. Notably, enrofloxacin application also induced the generation of some metagenome-assembled genomes (MAGs) carrying multiple ARGs, which were identified as novel species. Additionally, Enterobacteriaceae constituted a mobile ARG pool in aquaculture. Therefore, aquaculture provides potential wide environmental pathways for generation and spread of antibiotic resistance. Our findings of ARG temporal variations and dissemination pattern in aquaculture with artificial use of antibiotics are critical to the management of antibiotic resistance, which is of great ecosystem and health implications.202336356515
689480.9999Profiles 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
739290.9999Distribution of genetic elements associated with antibiotic resistance in treated and untreated animal husbandry waste and wastewater. Animal breeding for meat production based on swine, cattle, poultry, and aquaculture is an activity that generates several impacts on the environment, among them the spread of antibiotic resistance. There is a worldwide concern related to the massive use of antibiotics, which causes selective pressure on the microbial community, triggering bacteria that contain "antibiotic resistance genes." According to the survey here presented, antibiotic resistance-related genes such as tetracyclines (tet), erythromycin (erm), and sulfonamides (sul), as well as the genetic mobile element interferon (int), are the most reported genetic elements in qualitative and quantitative studies of swine, cattle, poultry, and aquaculture manure/wastewater. It has been observed that biological treatments based on waste composting and anaerobic digestion are effective in ARG removal, particularly for tet, bla, erm, and qnr (quinolone) genes. On the other hand, sul and intI genes were more persistent in such treatments. Tertiary treatments, such advanced oxidative processes, are suitable strategies to improve ARG reduction. In general temperature, hydraulic retention time, and penetration of sunlight are the main operational parameters for ARG reduction in treatments applied to animal waste, and therefore attention should be addressed to optimize their efficacy regarding ARG removal. Despite being reduced, the presence of ARG in treated effluents and in biosolids indicates that there is a potential risk of antibiotic resistance spread in nature, especially through the release of treated livestock waste into the environment.202133835340
7337100.9999Chlorine disinfection modifies the microbiome, resistome and mobilome of hospital wastewater - A nanopore long-read metagenomic approach. The aim of the present study was to analyze changes in the microbiome, resistome, and mobilome of hospital wastewater (HWW) induced by disinfection with chlorine compounds. Changes in bacterial communities and specific antibiotic resistance genes (ARGs) in HWW were determined with the use of a nanopore long-read metagenomic approach. The main hosts of ARGs in HWW were identified, and the mobility of resistance mechanisms was analyzed. Special attention was paid to the prevalence of critical-priority pathogens in the HWW microbiome, which pose the greatest threat to human health. The results of this study indicate that chlorine disinfection of HWW can induce significant changes in the structure of the total bacterial population and antibiotic resistant bacteria (ARB) communities, and that it can modify the resistome and mobilome of HWW. Disinfection favored the selection of ARGs, decreased their prevalence in HWW, while increasing their diversity. The mobility of the HWW resistome increased after disinfection. Disinfection led to the emergence of new drug resistance mechanisms in previously sensitive bacterial taxa. In conclusion, this study demonstrated that HWW disinfected with low (sublethal) concentrations of free chlorine significantly contributes to the mobility and transfer of drug resistance mechanisms (including critical mechanisms) between bacteria (including pathogens).202337595469
7341110.9999Metagenomic analysis of an urban resistome before and after wastewater treatment. Determining the effect of wastewater treatment in water resistome is a topic of interest for water quality, mainly under re-use and One-Health perspectives. The resistome, the plasmidome, and the bacterial community composition of samples from influents and treated effluents from a wastewater treatment plant located in Northern Portugal were studied using metagenomic techniques. Wastewater treatment contributed to reduce the abundance of resistance genes and of plasmid replicons, coinciding with a decline in the number of intrinsic resistance genes from Enterobacteriaceae, as well as with a reduction in the relative abundance of Firmicutes and Proteobacteria after treatment. These taxons comprise bacterial pathogens, including those belonging to the ESKAPE group, which encompasses bacteria with the highest risk of acquiring antibiotic resistance, being the most relevant hosts of resistance genes acquired through horizontal gene transfer. Our results support that wastewater treatment efficiently removes the hosts of antibiotic resistance genes and, consequently, the harboured antibiotic resistance genes. Principal component analysis indicates that the resistome and the bacterial composition clustered together in influent samples, while did not cluster in final effluent samples. Our results suggest that wastewater treatment mitigates the environmental dissemination of urban resistome, through the removal of the hosts harbouring mobile resistance genes.202032424207
7336120.9999Pathogenic and Indigenous Denitrifying Bacteria are Transcriptionally Active and Key Multi-Antibiotic-Resistant Players in Wastewater Treatment Plants. The global rise and spread of antibiotic resistance greatly challenge the treatment of bacterial infections. Wastewater treatment plants (WWTPs) harbor and discharge antibiotic resistance genes (ARGs) as environmental contaminants. However, the knowledge gap on the host identity, activity, and functionality of ARGs limits transmission and health risk assessment of the WWTP resistome. Hereby, a genome-centric quantitative metatranscriptomic approach was exploited to realize high-resolution qualitative and quantitative analyses of bacterial hosts of ARGs (i.e., multiresistance, pathogenicity, activity, and niches) in the 12 urban WWTPs. We found that ∼45% of 248 recovered genomes expressed ARGs against multiple classes of antibiotics, among which bacitracin and aminoglycoside resistance genes in Proteobacteria were the most prevalent scenario. Both potential pathogens and indigenous denitrifying bacteria were transcriptionally active hosts of ARGs. The almost unchanged relative expression levels of ARGs in the most resistant populations (66.9%) and the surviving ARG hosts including globally emerging pathogens (e.g., Aliarcobacter cryaerophilus) in treated WWTP effluent prioritize future examination on the health risks related to resistance propagation and human exposure in the receiving environment.202134282905
7389130.9999Temporal changes of antibiotic-resistance genes and bacterial communities in two contrasting soils treated with cattle manure. The emerging environmental spread of antibiotic-resistance genes (ARGs) and their subsequent acquisition by clinically relevant microorganisms is a major threat to public health. Animal manure has been recognized as an important reservoir of ARGs; however, the dissemination of manure-derived ARGs and the impacts of manure application on the soil resistome remain obscure. Here, we conducted a microcosm study to assess the temporal succession of total bacteria and a broad spectrum of ARGs in two contrasting soils following manure application from cattle that had not been treated with antibiotics. High-capacity quantitative PCR detected 52 unique ARGs across all the samples, with β-lactamase as the most dominant ARG type. Several genes of soil indigenous bacteria conferring resistance to β-lactam, which could not be detected in manure, were found to be highly enriched in manure-treated soils, and the level of enrichment was maintained over the entire course of 140 days. The enriched β-lactam resistance genes had significantly positive relationships with the relative abundance of the integrase intI1 gene, suggesting an increasing mobility potential in manure-treated soils. The changes in ARG patterns were accompanied by a significant effect of cattle manure on the total bacterial community compositions. Our study indicates that even in the absence of selective pressure imposed by agricultural use of antibiotics, manure application could still strongly impact the abundance, diversity and mobility potential of a broad spectrum of soil ARGs. Our findings are important for reliable prediction of ARG behaviors in soil environment and development of appropriate strategies to minimize their dissemination.201626712351
6883140.9999Metagenomic insights into the profile of antibiotic resistomes in sediments of aquaculture wastewater treatment system. To meet the rapidly growing global demand for aquaculture products, large amounts of antibiotics were used in aquaculture, which might accelerate the evolution of antibiotic-resistant bacteria (ARB) and the propagation of antibiotic genes (ARGs). In our research, we revealed the ARGs profiles, their co-occurrence with mobile genetic elements (MGEs), and potential hosts in sediments of a crab pond wastewater purification system based on metagenomic analysis. The residual antibiotic seems to increase the propagation of ARGs in the crab pond, but there was no clear relationship between a given antibiotic type and the corresponding resistance genes. The effect of aquaculture on sediment was not as profound as that of other anthropogentic activities, but increased the relative abundance of sulfonamide resistance gene. A higher abundance of MGEs, especially plasmid, increased the potential ARGs dissemination risk in crab and purification ponds. Multidrug and sulfonamide resistance genes had greater potential to transfer because they were more frequently carried by MGEs. The horizontal gene transfer was likely to occur among a variety of microorganisms, and various ARGs hosts including Pseudomonas, Acinetobacter, Escherichia, and Klebsiella were identified. Bacterial community influenced the composition of ARG hosts, and Proteobacteria was the predominant hosts. Overall, our study provides novel insights into the environmental risk of ARGs in sediments of aquaculture wastewater treatment system.202234963542
3252150.9999Exploring phylogenetic diversity of antibiotic resistance genes in activated sludge: A host and genomic location perspective. Antibiotic resistance has emerged as a significant global public health issue. The environmental behaviors of antibiotic resistance genes (ARGs), such as their persistence and horizontal transfer, have been extensively investigated. However, the genetic diversity characteristics of ARGs remain underexplored, which limits a comprehensive analysis of their roles in the environment. In this study, we examined the genetic diversity of ARGs in activated sludge from 44 wastewater treatment plants in five countries. Most ARGs detected in activated sludge possessed multiple variants, with a median of 48. The number of variants of gd-ARGs varied among different resistance mechanisms and ARG types. The number of potential variants of ARGs was strongly correlated with host diversity. Pseudomonas spp. and Klebsiella pneumoniae, identified as pathogenic bacteria, harbored multiple ARGs and had the most variants. Most ARG subtypes on plasmids and chromosomes showed divergent evolution. Molecular docking of AdeH proteins revealed that genomic location affects tetracycline binding energy. The findings underscore the intricate interplay between genetic variation and environmental adaptation in ARGs, offering a novel perspective on the spread of antibiotic resistance.202540216056
7467160.9999Co-occurrence of antibiotic and metal resistance genes revealed in complete genome collection. The high frequency of antibiotic resistance is a global public health concern. More seriously, widespread metal pressure in the environment may facilitate the proliferation of antibiotic resistance via coselection of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs). Given the lack of comprehensive understanding of the ARG and MRG coselection, in this study both abundance relationship and genetic linkage between ARGs and MRGs were rigorously investigated by performing a genomic analysis of a large complete genome collection. Many more ARGs were enriched in human-associated bacteria compared with those subjected to less anthropogenic interference. The signatures of ARG and MRG co-occurrence were much more frequent and the distance linkages between ARGs and MRGs were much more intimate in human pathogens than those less human-associated bacteria. Moreover, the co-occurrence structures in the habitat divisions were significantly different, which could be attributed to their distinct gene transfer potentials. More exogenous ARGs and MRGs on the genomes of human pathogens indicated the importance of recent resistance acquisition in resistome development of human commensal flora. Overall, the study emphasizes the potential risk associated with ARG and MRG coselection of both environmental and medical relevance.201727959344
6895170.9999Effects 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
7504180.9999Contribution of antibiotics to the fate of antibiotic resistance genes in anaerobic treatment processes of swine wastewater: A review. Antibiotic resistance genes (ARGs) in water environment have become a global health concern. Swine wastewater is widely considered to be one of the major contributors for promoting the proliferation of ARGs in water environments. This paper comprehensively reviews and discusses the occurrence and removal of ARGs in anaerobic treatment of swine wastewater, and contributions of antibiotics to the fate of ARGs. The results reveal that ARGs' removal is unstable during anaerobic processes, which negatively associated with the presence of antibiotics. The abundance of bacteria carrying ARGs increases with the addition of antibiotics and results in the spread of ARGs. The positive relationship was found between antibiotics and the abundance and transfer of ARGs in this review. However, it is necessary to understand the correlation among antibiotics, ARGs and microbial communities, and obtain more knowledge about controlling the dissemination of ARGs in the environment.202031917094
7425190.9999Antibiotic resistant bacteria and genes in wastewater treatment plants: From occurrence to treatment strategies. This study aims to discuss the following: (1) occurrence and proliferation of antibiotic resistance in wastewater treatment plants (WWTPs); (2) factors influencing antibiotic resistance bacteria and genes in WWTPs; (3) tools to assess antibiotic resistance in WWTPs; (4) environmental contamination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from WWTPs; (5) effects of ARB and ARGs from WWTPs on human health; and (6) treatment strategies. In general, resistant and multi-resistant bacteria, including Enterobacteriaceae, Pseudomonas aeruginosa, and Escherichia coli, exist in various processes of WWTPs. The existence of ARB and ARGs results from the high concentration of antibiotics in wastewater, which promote selective pressures on the local bacteria present in WWTPs. Thus, improving wastewater treatment technology and avoiding the misuse of antibiotics is critical to overcoming the threat of proliferation of ARBs and ARGs. Numerous factors can affect the development of ARB and ARGs in WWTPs. Abiotic factors can affect the bacterial community dynamics, thereby, affecting the applicability of ARB during the wastewater treatment process. Furthermore, the organic loads and other nutrients influence bacterial survival and growth. Specifically, molecular methods for the rapid characterization and detection of ARBs or their genes comprise DNA sequencing, real-time PCR, simple and multiplex PCR, and hybridization-based technologies, including micro- and macro-arrays. The reuse of effluent from WWTPs for irrigation is an efficient method to overcome water scarcity. However, there are also some potential environmental risks associated with this practice, such as increase in the levels of antibiotic resistance in the soil microbiome. Human mortality rates may significantly increase, as ARB can lead to resistance among several types of antibiotics or longer treatment times. Some treatment technologies, such as anaerobic and aerobic treatment, coagulation, membrane bioreactors, and disinfection processes, are considered potential techniques to restrict antibiotic resistance in the environment.202235679932