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780400.9885Electrochemical flow-through disinfection reduces antibiotic resistance genes and horizontal transfer risk across bacterial species. Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), as emerging pollutants, are released into environment, increasing the risk of horizontal gene transfer (HGT). However, a limited number of studies quantified the effects of ARB disinfection on the HGT risk. This study investigated the inactivation of E. coli 10667 (sul) and the release and removal of ARGs using an electrochemical flow-through reactor (EFTR). Furthermore, the transfer frequencies and potential mechanisms of HGT after disinfection were explored using non-resistant E. coli GMCC 13373 as the recipient and E. coli DH5α carrying plasmid RP4 as the donor. A threshold of current density (0.25 mA/cm(2)) was observed to destroy cells and release intracellular ARGs (iARGs) to increase extracellular ARGs (eARGs) concentration. The further increase in the current density to 1 mA/cm(2) resulted in the decline of eARGs concentration due to the higher degradation rate of eARGs than the release rate of iARGs. The performance of ARGs degradation and HGT frequency by EFTR were compared with those of conventional disinfection processes, including chlorination and ultraviolet radiation (UV). A higher ARGs degradation (83.46%) was observed by EFTR compared with that under chlorination (10.23%) and UV (27.07%). Accordingly, EFTR reduced the HGT frequency (0.69) of released ARGs into the recipient (Forward transfer), and the value was lower than that by chlorination (2.69) and UV (1.73). Meanwhile, the surviving injured E. coli 10667 (sul) with increased cell permeability was transferred by plasmid RP4 from the donor (Reverse transfer) with a higher frequency of 0.33 by EFTR compared with that under chlorination (0.26) and UV (0.16). In addition, the sul3 gene was the least resistant to EFTR than sul1 and sul2 gene. These findings provide important insights into the mechanism of HGT between the injured E. coli 10667 (sul) and environmental bacteria. EFTR is a promising disinfection technology for preventing the spread of antibiotic resistance.202235085844
650610.9884Mitigating antimicrobial resistance through effective hospital wastewater management in low- and middle-income countries. Hospital wastewater (HWW) is a significant environmental and public health threat, containing high levels of pollutants such as antibiotic-resistant bacteria (ARB), antibiotic-resistant genes (ARGs), antibiotics, disinfectants, and heavy metals. This threat is of particular concern in low- and middle-income countries (LMICs), where untreated effluents are often used for irrigating vegetables crops, leading to direct and indirect human exposure. Despite being a potential hotspot for the spread of antimicrobial resistance (AMR), existing HWW treatment systems in LMICs primarily target conventional pollutants and lack effective standards for monitoring the removal of ARB and ARGs. Consequently, untreated or inadequately treated HWW continues to disseminate ARB and ARGs, exacerbating the risk of AMR proliferation. Addressing this requires targeted interventions, including cost-effective treatment solutions, robust AMR monitoring protocols, and policy-driven strategies tailored to LMICs. This perspective calls for a paradigm shift in HWW management in LMIC, emphasizing the broader implementation of onsite treatment systems, which are currently rare. Key recommendations include developing affordable and contextually adaptable technologies for eliminating ARB and ARGs and enforcing local regulations for AMR monitoring and control in wastewater. Addressing these challenges is essential for protecting public health, preventing the environmental spread of resistance, and contributing to a global effort to preserve the efficacy of antibiotics. Recommendations include integrating scalable onsite technologies, leveraging local knowledge, and implementing comprehensive AMR-focused regulatory frameworks.202439944563
652520.9883The Role of Water as a Reservoir for Antibiotic-Resistant Bacteria. Water systems serve as multifaceted environmental pools for antibiotic-resistant bacteria (ARB) and resistance genes (ARGs), influencing human, animal, and ecosystem health. This review synthesizes current understanding of how antibiotics, ARB, and ARGs enter surface, ground, and drinking waters via wastewater discharge, agricultural runoff, hospital effluents, and urban stormwater. We highlight key mechanisms of biofilm formation, horizontal gene transfer, and co-selection by chemical stressors that facilitate persistence and spread. Case studies illustrate widespread detection of clinically meaningful ARB (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and mobile ARGs (e.g., sul1/2, tet, bla variants) in treated effluents, recycled water, and irrigation return flows. The interplay between treatment inefficiencies and environmental processes underscores the need for advanced treatment technologies, integrated monitoring, and policy interventions. Addressing these challenges is critical to curbing the environmental dissemination of resistance and protecting human and ecosystem health.202540867958
726830.9883Deciphering Multidrug-Resistant Plasmids in Disinfection Residual Bacteria from a Wastewater Treatment Plant. Current disinfection processes pose an emerging environmental risk due to the ineffective removal of antibiotic-resistant bacteria, especially disinfection residual bacteria (DRB) carrying multidrug-resistant plasmids (MRPs). However, the characteristics of DRB-carried MRPs are poorly understood. In this study, qPCR analysis reveals that the total absolute abundance of four plasmids in postdisinfection effluent decreases by 1.15 log units, while their relative abundance increases by 0.11 copies/cell compared to investigated wastewater treatment plant (WWTP) influent. We obtain three distinctive DRB-carried MRPs (pWWTP-01-03) from postdisinfection effluent, each carrying 9-11 antibiotic-resistant genes (ARGs). pWWTP-01 contains all 11 ARGs within an ∼25 Kbp chimeric genomic island showing strong patterns of recombination with MRPs from foodborne outbreaks and hospitals. Antibiotic-, disinfectant-, and heavy-metal-resistant genes on the same plasmid underscore the potential roles of disinfectants and heavy metals in the coselection of ARGs. Additionally, pWWTP-02 harbors an adhesin-type virulence operon, implying risks of both antibiotic resistance and pathogenicity upon entering environments. Furthermore, some MRPs from DRB are capable of transferring and could confer selective advantages to recipients under environmentally relevant antibiotic pressure. Overall, this study advances our understanding of DRB-carried MRPs and highlights the imminent need to monitor and control wastewater MRPs for environmental security.202438574343
317940.9882Deciphering the mobility, pathogenic hosts, and co-selection of antibiotic resistance genes in untreated wastewater from three different hospitals. OBJECTIVE: Antibiotic resistance genes (ARGs) in hospital wastewater pose significant environmental and public health risks, yet the co-selection mechanisms involving metal/biocide resistance genes (MRGs/BRGs) and the role of mobile genetic elements (MGEs) remain poorly characterized. This study aimed to comprehensively assess the abundance, mobility, pathogenic hosts, and co-selection patterns of ARGs, MRGs, and BRGs in untreated wastewater from three types of hospitals. METHODS: Untreated wastewater samples from nine sources across three hospital types (general, traditional Chinese medicine, and dental) were analyzed using metagenomic sequencing and assembly. ARGs, MRGs, and BRGs were identified via the SARG and BacMet databases. ARG hosts, mobility, and MGE co-occurrence were analyzed using PlasFlow and MOB-suite, with risk levels evaluated alongside pathogenic bacteria databases. RESULTS: A total of 1911 ARGs (222 subtypes), 1662 MRGs (167 subtypes), and 916 BRGs (139 subtypes) were detected. Tetracycline, multidrug, and β-lactam resistance genes were predominant, with 46.43 % of ARGs being plasmid-associated. Key pathogens including Klebsiella pneumoniae and Enterococcus spp. harbored high-risk ARGs such as KPC-2 and NDM-1. Notably, 76.2 % of ARGs in traditional Chinese medicine hospital wastewater were classified as high-risk. Significant co-occurrence of ARGs with MGEs (e.g., DDE recombinases) and MRGs/BRGs was observed, underscoring the role of horizontal gene transfer and co-selection. CONCLUSION: Untreated hospital wastewater represents a significant reservoir of ARGs, with risks exacerbated by pathogenic hosts, MGE-mediated HGT, and metal/biocide co-selection. These findings underscore the urgent need for optimized wastewater treatment strategies to curb the spread of antibiotic resistance and inform future intervention efforts.202541067299
753150.9882Microplastics exacerbate co-occurrence and horizontal transfer of antibiotic resistance genes. Microplastic pollution is a rising environmental issue worldwide. Microplastics can provide a niche for the microbiome, especially for antibiotic-resistant bacteria, which could increase the transmission of antibiotic resistance genes (ARGs). However, the interactions between microplastics and ARGs are still indistinct in environmental settings. Microplastics were found to be significantly correlated with ARGs (p < 0.001), based on the analysis of samples taken from a chicken farm and its surrounding farmlands. Analysis of chicken feces revealed the highest abundance of microplastics (14.9 items/g) and ARGs (6.24 ×10(8) copies/g), suggesting that chicken farms could be the hotspot for the co-spread of microplastics and ARGs. Conjugative transfer experiments were performed to investigate the effects of microplastic exposure for different concentrations and sizes on the horizontal gene transfer (HGT) of ARGs between bacteria. Results showed that the microplastics significantly enhanced the bacterial conjugative transfer frequency by 1.4-1.7 folds indicating that microplastics could aggravate ARG dissemination in the environment. Potential mechanisms related to the up-regulation of rpoS, ompA, ompC, ompF, trbBp, traF, trfAp, traJ, and down-regulation of korA, korB, and trbA were induced by microplastics. These findings highlighted the co-occurrence of microplastics and ARGs in the agricultural environment and the exacerbation of ARGs' prevalence via rising the HGT derived from microplastics.202336878032
679460.9882Beyond cyanotoxins: increased Legionella, antibiotic resistance genes in western Lake Erie water and disinfection-byproducts in their finished water. BACKGROUND: Western Lake Erie is suffering from harmful cyanobacterial blooms, primarily toxic Microcystis spp., affecting the ecosystem, water safety, and the regional economy. Continued bloom occurrence has raised concerns about public health implications. However, there has been no investigation regarding the potential increase of Legionella and antibiotic resistance genes in source water, and disinfection byproducts in municipal treated drinking water caused by these bloom events. METHODS: Over 2 years, source water (total n = 118) and finished water (total n = 118) samples were collected from drinking water plants situated in western Lake Erie (bloom site) and central Lake Erie (control site). Bloom-related parameters were determined, such as microcystin (MC), toxic Microcystis, total organic carbon, N, and P. Disinfection byproducts (DBPs) [total trihalomethanes (THMs) and haloacetic acids (HAAs)] were assessed in finished water. Genetic markers for Legionella, antibiotic resistance genes, and mobile genetic elements were quantified in source and finished waters. RESULTS: Significantly higher levels of MC-producing Microcystis were observed in the western Lake Erie site compared to the control site. Analysis of DBPs revealed significantly elevated THMs concentrations at the bloom site, while HAAs concentrations remained similar between the two sites. Legionella spp. levels were significantly higher in the bloom site, showing a significant relationship with total cyanobacteria. Abundance of ARGs (tetQ and sul1) and mobile genetic elements (MGEs) were also significantly higher at the bloom site. DISCUSSION: Although overall abundance decreased in finished water, relative abundance of ARGs and MGE among total bacteria increased after treatment, particularly at the bloom site. The findings underscore the need for ongoing efforts to mitigate bloom frequency and intensity in the lake. Moreover, optimizing water treatment processes during bloom episodes is crucial to maintain water quality. The associations observed between bloom conditions, ARGs, and Legionella, necessitate future investigations into the potential enhancement of antibiotic-resistant bacteria and Legionella spp. due to blooms, both in lake environments and drinking water distribution systems.202337700867
320670.9882High pollution and health risk of antibiotic resistance genes in rural domestic sewage in southeastern China: A study combining national-scale distribution and machine learning. Rural domestic sewage has emerged as an important reservoir of antibiotic resistance genes (ARGs) under rapid urbanization, while the national-scale geographical patterns and risks of ARGs remaining unclear. We investigated ARG pollution in rural domestic sewage across 39 sites in 22 Chinese provinces using metagenomic sequencing, identifying 702 ARG subtypes across 21 types. Multidrug resistance genes were predominant in the shared ARGs, accounting for 58.96 % of the total ARG abundance. Host bacteria analysis revealed Klebsiella pneumoniae and Escherichia coli were the main pathogenic-resistant bacteria. Southeastern China exhibited the highest level of ARG pollution in rural domestic sewage, followed by south-central, northern, and western. This ARG pollution was primarily caused by human/animal feces based on ARG indicators. Partial least-squares path model and partial redundancy analysis highlighted antibiotics as the primary driver, explaining 24.16 % of ARG variation, with sulfamethazine, norfloxacin, and ofloxacin identified as priority control targets. Risk assessment by calculating the risk index indicated 24.58 % of detected ARGs posed potential health threats, particularly multidrug resistance. Machine learning models predicted higher ARG risks in rural domestic sewage from southeastern China with intensive human activity. This study underscores the crucial impact of antibiotics in ARG proliferation and risk in rural domestic sewage.202540701495
717580.9881Key Contribution and Risk of Airborne Antibiotic Resistance: Total Suspended Particles or Settled Dust? The atmosphere is an important environmental medium in spreading antimicrobial resistance (AMR) in animal farming systems, yet the exposure risks associated with airborne pathways remain underexplored. This study employed metagenomic sequencing to investigate the airborne transmission of AMR in chicken farms (i.e., chicken feces, total suspended particles (TSP), and dust) and its exposure risks on the gut and nasal cavities of workers, office staff, and nearby villagers. Results revealed that TSP exhibited greater abundance, diversity, and transfer potential of antibiotic resistance genes (ARGs) compared to dust. The abundance of airborne resistome decreased with distance from the chicken house, and ARGs were estimated to spread up to 9.48 km within 1 h. While the gut resistome of workers and villagers showed limited differences, emerging tet(X) variants and high-risk dfrA remain future concerns. More nasal resistome was attributable to TSP compared to dust. Workers faced significantly higher inhalable exposures to antibiotic-resistant bacteria (ARB) and human pathogenic antibiotic-resistant bacteria (HPARB), exceeding those of office staff and villagers by an order of magnitude. We also compiled lists of high-risk and potential-risk airborne ARGs to inform monitoring. These findings highlight the need for regular air disinfection in animal farms and better protective measures for workers.202540434009
721590.9881High-throughput qPCR profiling of antimicrobial resistance genes and bacterial loads in wastewater and receiving environments. Wastewater treatment plants (WWTPs) are hot spots for the acquisition and spread of antimicrobial resistance (AMR). This regional-based study quantified antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and bacteria in hospital and community-derived wastewater and receiving environments, using high-throughput qPCR (HT-qPCR). This is the first study to apply Resistomap's Antibiotic Resistance Gene Index (ARGI) as a standardised metric to find the overall AMR level across different WWTPs. ARGI of WWTPs ranged from 2.0 to 2.3, indicating higher relative ARG levels than the mean European ARGI of 2.0, but lower than the global mean of 2.4. The highest diversity and abundance of ARGs were observed in untreated hospital and community wastewater. The reduction of total ARGs during wastewater treatment (0.2-2 logs) and bacteria (0.3-1.5 logs) varied spatio-temporally across the WWTPs. Despite a decrease in ARG and bacterial abundance in treated effluents, substantial loads were still released into receiving environments. Notably, ARG levels in coastal sediments were comparable to those in untreated wastewater, and most ARGs were shared between wastewater and receiving environments, highlighting the impact of wastewater discharge on these ecosystems. Sewage outfall exposure increased ARGs in shellfish, emphasising risks to shellfish hygiene. This study provides evidence to inform policymaking, emphasising advanced wastewater treatment methods and combined sewer overflow (CSO) management to mitigate ARG release, protecting water users and the food chain.202540127809
8498100.9881Per- and polyfluoroalkyl substances exacerbate the prevalence of plasmid-borne antibiotic resistance genes by enhancing natural transformation, in vivo stability, and expression in bacteria. Per- and polyfluoroalkyl substances (PFAS) as emerging pollutants are ubiquitous and disrupt biological processes across water boundaries. Their coexistence with antibiotic resistance genes (ARGs) in water matrix is associated with the spread of ARGs via conjugative transfer, posing a threat to public health. However, their role in natural transformation-where microorganisms actively take up extracellular ARGs (eARGs)-and the subsequent persistence and expression of ARGs after transformation remains poorly understood. Here, we demonstrated that environmentally relevant concentrations (0.1-10 µg/L) of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), two typical PFAS, increased transformation frequencies by 2.54- and 3.26-fold, respectively. This increase was driven by increased cell envelope permeability, biofilm formation, reactive oxygen species (ROS) production, and upregulation of DNA uptake genes. At higher concentrations (100 µg/L), PFAS inhibited transformation. Nevertheless, PFOA and PFOS at all tested concentrations promoted long-term plasmid in vivo stability, reducing plasmid loss rates from 68.5% to 6% and 38.7%, respectively. Furthermore, they induced ARGs expression in transformants by up to 1.33- and 1.37-fold. Our findings revealed that PFOA and PFOS impacted the spread, persistence, and expression of ARGs, from extracellular uptake to intracellular activity in bacteria. These results highlight the underestimated environmental health risks posed by PFAS and underscore the intricate chemical and biological co-contamination in aquatic ecosystems and wastewater treatment.202539706060
6713110.9881Human Colonization with Antibiotic-Resistant Bacteria from Nonoccupational Exposure to Domesticated Animals in Low- and Middle-Income Countries: A Critical Review. Data on community-acquired antibiotic-resistant bacterial infections are particularly sparse in low- and middle-income countries (LMICs). Limited surveillance and oversight of antibiotic use in food-producing animals, inadequate access to safe drinking water, and insufficient sanitation and hygiene infrastructure in LMICs could exacerbate the risk of zoonotic antibiotic resistance transmission. This critical review compiles evidence of zoonotic exchange of antibiotic-resistant bacteria (ARB) or antibiotic resistance genes (ARGs) within households and backyard farms in LMICs, as well as assesses transmission mechanisms, risk factors, and environmental transmission pathways. Overall, substantial evidence exists for exchange of antibiotic resistance between domesticated animals and in-contact humans. Whole bacteria transmission and horizontal gene transfer between humans and animals were demonstrated within and between households and backyard farms. Further, we identified water, soil, and animal food products as environmental transmission pathways for exchange of ARB and ARGs between animals and humans, although directionality of transmission is poorly understood. Herein we propose study designs, methods, and topical considerations for priority incorporation into future One Health research to inform effective interventions and policies to disrupt zoonotic antibiotic resistance exchange in low-income communities.202235947446
3512120.9880Profiling of intracellular and extracellular antibiotic resistance genes in tap water. Antibiotic resistance genes (ARGs) have gained global attention due to their public health threat. Extracelluar ARGs (eARGs) can result in the dissemination of antibiotic resistance via free-living ARGs in natural environments, where they promote ARB transmission in drinking water distribution systems. However, eARG pollution in tap water has not been well researched. In this study, concentrations of eARGs and intracellular ARGs (iARGs) in tap water, sampled at Tianjin, China, were investigated for one year. Fourteen eARG types were found at the highest concentration of 1.3 × 10(5) gene copies (GC)/L. TetC was detected in 66.7% of samples, followed by sul1, sul2, and qnrA with the same detection frequency of 41.7%. Fifteen iARGs (including tetA, tetB, tetM, tetQ, tetX, sul1, sul2, sul3, ermB, blaTEM, and qnrA) were continuously detected in all collected tap water samples with sul1 and sul2 the most abundant. Additionally, both eARG and iARG concentrations in tap water presented a seasonal pattern with most abundant prevalence in summer. The concentration of observed intracellular sulfonamide resistance genes showed a significantly positive correlation with total nitrogen concentrations. This study suggested that eARG and iARG pollution of drinking water systems pose a potential risk to human public health.201930448547
6861130.9880Investigating the antibiotic resistance genes and mobile genetic elements in water systems impacted with anthropogenic pollutants. A wide range of pollutants, including heavy metals, endocrine-disrupting chemicals (EDCs), residual pesticides, and pharmaceuticals, are present in various water systems, many of which strongly drive the proliferation and dissemination of antimicrobial resistance genes (ARGs), heightening the antimicrobial resistance (AMR) crisis and creating a critical challenge for environmental and health management worldwide. This study addresses the impact of anthropogenic pollutants on AMR through an extensive analysis of ARGs and mobile genetic elements (MGEs) in urban wastewater, source water, and drinking water supplies in India. Results indicated that bla(TEM) and bla(CTXM-32) were the dominant ARGs across all water systems, underscoring the prevalence and dominance of resistance against β-lactam antibiotics. Moreover, transposase genes such as tnpA-02, tnp-04, and tnpA-05 were detected across all water systems, indicating potential mechanisms for genetic transfer. The ubiquitous presence of intI-1 and clin-intI-1 genes underscores the widespread dissemination of MGEs, posing challenges for water quality management. Besides, human pathogenic bacteria such as Clostridium, Acinetobacter, and Legionella were also detected, highlighting potential health risks associated with contaminated water. The identified pathogenic bacterial genera belong to the phyla Pseudomonadota and Firmicutes. Leveraging linear regression to analyze correlations between EDCs and ARG-MGEs provides deeper insights into their interconnected dynamics. DMP showed a significant influence on tnpA-02 (p = 0.005), tnpA-07 (p = 0.015), sul-1 (p = 0.008), intI-1 (p = 0.03), and clin-intI1 (p = 0.012), while DiNOP demonstrated a very high impact on tnpA-05 (p = 0). Redundancy analysis revealed significant correlations between resistance genes and EDCs. Additionally, environmental parameters such as pH were highly correlated with the majority of MGEs and bla(CTXM-32). Furthermore, we found that F(-), NO(-3), and SO(4)(-2) were significantly correlated with sul-1, with F(-) exhibiting the highest impact, emphasizing the intricate interplay of pollutants in driving AMR. Understanding these interconnected factors is crucial for developing effective strategies and sustainable solutions to combat antibiotic resistance in environmental settings.202539824274
7540140.9880Extended chloramination significantly enriched intracellular antibiotic resistance genes in drinking water treatment plants. Chloramination and chlorination are both strong barriers that prevent the transmission of potential pathogens to humans through drinking water. However, the comparative effects of chloramination and chlorination on the occurrence of antibiotic resistance genes (ARGs) in drinking water treatment plants (DWTPs) remain unknown. Herein, the antibiotic resistome in water before and after chloramination or chlorination was analyzed through metagenomic sequencing and then verified through quantitative real-time polymerase chain reaction (qPCR). After the treatment of 90 min, chloramination led to higher enrichment of the total relative abundance of intracellular ARGs (iARGs) in water than chlorination, whereas chlorination facilitated the release of more extracellular ARGs (eARGs) than chloramination. According to redundancy and Pearson's analyses, the total concentration of the observed iARGs in the finished water exhibited a strong positive correlation with ammonium nitrogen (NH(4)(+)-N) concentration, presenting a linear upward trend with an increase in the NH(4)(+)-N concentration. This indicated that NH(4)(+)-N is a crucial driving factor for iARG accumulation during chloramination. iARG enrichment ceases if the duration of chloramination is shortened to 40 min, suggesting that shortening the duration would be a better strategy for controlling iARG enrichment in drinking water. These findings emphasized the potential risk of antibiotic resistance after extended chloramination, shedding light on the control of transmission of antibiotic-resistant bacteria through water by optimizing disinfection procedures in DWTPs.202336739658
6858150.9880Antibiotic resistance genes risks in relation to host pathogenicity and mobility in a typical hospital wastewater treatment process. Hospital wastewaters (HWWs) serve as critical reservoirs for disseminating antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). However, the dynamics and noteworthy shifts of ARGs and their associated pathogenicity, mobility, and resistome risks during HWWs treatment processes remain poorly understood. Utilizing metagenomic sequencing and assembly, we identified 817 ARG subtypes conferring resistance to 20 classes of antibiotics across 18 HWW samples from influent to effluent. Genes encoding resistance to multidrug, aminoglycoside and beta_lactam were the most prevalent ARG types, reflecting patterns observed in clinical settings. On-site treatment efforts decreased the relative abundance of ARGs by 77.4% from influent to secondary sedimentation, whereas chlorine disinfection significantly increased their abundance in the final effluent. Deterministic processes primarily drove the taxonomic assembly, with Proteobacteria being the most abundant phylum and serving as the primary host for 15 ARG types. Contig-based analysis further revealed 114 pathogenic ARB, with Escherichia coli, Pseudomonas alcaligenes, and Pseudomonas aeruginosa exhibiting multidrug-resistant. The contributions of host bacteria and pathogenic ARB varied throughout wastewater treatment. In addition, 7.10%-31.0 % ARGs were flanked by mobile genetic elements (MGEs), predominantly mediated by transposase (74.1%). Notably, tnpA exhibited the highest potential for ARG dissemination, frequently co-occurring with beta-lactam resistance genes (35.2%). Considering ARG profiles, pathogenic hosts, and transferability, raw influent exhibited the highest antibiotic resistome risk index (ARRI), followed by the final effluent. Chlorine disinfection exacerbated resistome risks by inducing potential pathogenic ARB and mobile ARGs, posing threats to the receiving environment. This study delineates ARG occurrence patterns, highlights mechanisms of ARG carriage and horizontal gene transfer, and provides insights for assessing resistance risks and prioritizing interventions in clinical settings.202438964571
8001160.9879Exploring resistomes and microbiomes in pilot-scale microalgae-bacteria wastewater treatment systems for use in low-resource settings. Antibiotic resistance genes (ARGs) released into the environment are an emerging human and environmental health concern, including ARGs spread in wastewater treatment effluents. In low-to-middle income countries (LMICs), an alternate wastewater treatment option instead of conventional systems are low-energy, high-rate algal ponds (HRAP) that use microalgae-bacteria aggregates (MABA) for waste degradation. Here we studied the robustness of ARG removal in MABA-based pilot-scale outdoor systems for 140 days of continuous operation. The HRAP system successfully removed 73 to 88 % chemical oxygen demand and up to 97.4 % ammonia, with aggregate size increasing over operating time. Fourteen ARG classes were identified in the HRAP influent, MABA, and effluent using metagenomics, with the HRAP process reducing total ARG abundances by up to 5-fold from influent to effluent. Parallel qPCR analyses showed the HRAP system significantly reduced exemplar ARGs (p < 0.05), with 1.2 to 4.9, 2.7 to 6.3, 0 to 1.5, and 1.2 to 4.8 log-removals for sul1, tetQ, bla(KPC), and intl1 genes, respectively. Sequencing of influent, effluent and MABAs samples showed associated microbial communities differed significantly, with influent communities by Enterobacteriales (clinically relevant ARGs carrying bacteria), which were less evident in MABA and effluent. In this sense, such bacteria might be excluded from MABA due to their good settling properties and the presence of antimicrobial peptides. Microalgae-bacteria treatment systems steadily reduced ARGs from wastewater during operation time, using sunlight as the energetic driver, making them ideal for use in LMIC wastewater treatment applications.202337080313
7267170.9879Antimicrobial resistance transmission in the environmental settings through traditional and UV-enabled advanced wastewater treatment plants: a metagenomic insight. BACKGROUND: Municipal wastewater treatment plants (WWTPs) are pivotal reservoirs for antibiotic-resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). Selective pressures from antibiotic residues, co-selection by heavy metals, and conducive environments sustain ARGs, fostering the emergence of ARB. While advancements in WWTP technology have enhanced the removal of inorganic and organic pollutants, assessing ARG and ARB content in treated water remains a gap. This metagenomic study meticulously examines the filtration efficiency of two distinct WWTPs-conventional (WWTPC) and advanced (WWTPA), operating on the same influent characteristics and located at Aligarh, India. RESULTS: The dominance of Proteobacteria or Pseudomonadota, characterized the samples from both WWTPs and carried most ARGs. Acinetobacter johnsonii, a prevailing species, exhibited a diminishing trend with wastewater treatment, yet its persistence and association with antibiotic resistance underscore its adaptive resilience. The total ARG count was reduced in effluents, from 58 ARGs, representing 14 distinct classes of antibiotics in the influent to 46 and 21 in the effluents of WWTPC and WWTPA respectively. However, an overall surge in abundance, particularly influenced by genes such as qacL, bla(OXA-900), and rsmA was observed. Numerous clinically significant ARGs, including those against aminoglycosides (AAC(6')-Ib9, APH(3'')-Ib, APH(6)-Id), macrolides (EreD, mphE, mphF, mphG, mphN, msrE), lincosamide (lnuG), sulfonamides (sul1, sul2), and beta-lactamases (bla(NDM-1)), persisted across both conventional and advanced treatment processes. The prevalence of mobile genetic elements and virulence factors in the effluents possess a high risk for ARG dissemination. CONCLUSIONS: Advanced technologies are essential for effective ARG and ARB removal. A multidisciplinary approach focused on investigating the intricate association between ARGs, microbiome dynamics, MGEs, and VFs is required to identify robust indicators for filtration efficacy, contributing to optimized WWTP operations and combating ARG proliferation across sectors.202540050994
7576180.9879Spatial 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
6686190.9878The Impact of Wastewater on Antimicrobial Resistance: A Scoping Review of Transmission Pathways and Contributing Factors. BACKGROUND/OBJECTIVES: Antimicrobial resistance (AMR) is a global issue driven by the overuse of antibiotics in healthcare, agriculture, and veterinary settings. Wastewater and treatment plants (WWTPs) act as reservoirs for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The One Health approach emphasizes the interconnectedness of human, animal, and environmental health in addressing AMR. This scoping review analyzes wastewater's role in the AMR spread, identifies influencing factors, and highlights research gaps to guide interventions. METHODS: This scoping review followed the PRISMA-ScR guidelines. A comprehensive literature search was conducted across the PubMed and Web of Science databases for articles published up to June 2024, supplemented by manual reference checks. The review focused on wastewater as a source of AMR, including hospital effluents, industrial and urban sewage, and agricultural runoff. Screening and selection were independently performed by two reviewers, with conflicts resolved by a third. RESULTS: Of 3367 studies identified, 70 met the inclusion criteria. The findings indicated that antibiotic residues, heavy metals, and microbial interactions in wastewater are key drivers of AMR development. Although WWTPs aim to reduce contaminants, they often create conditions conducive to horizontal gene transfer, amplifying resistance. Promising interventions, such as advanced treatment methods and regulatory measures, exist but require further research and implementation. CONCLUSIONS: Wastewater plays a pivotal role in AMR dissemination. Targeted interventions in wastewater management are essential to mitigate AMR risks. Future studies should prioritize understanding AMR dynamics in wastewater ecosystems and evaluating scalable mitigation strategies to support global health efforts.202540001375