Effect of Powdered Activated Carbon as Advanced Step in Wastewater Treatments on Antibiotic Resistant Microorganisms. - Related Documents




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760901.0000Effect of Powdered Activated Carbon as Advanced Step in Wastewater Treatments on Antibiotic Resistant Microorganisms. BACKGROUND: Conventional wastewater treatment plants discharge significant amounts of antibiotic resistant bacteria and antibiotic resistance genes into natural water bodies contributing to the spread of antibiotic resistance. Some advanced wastewater treatment technologies have been shown to effectively decrease the number of bacteria. Nevertheless, there is still a lack of knowledge about the effectiveness of these treatments on antibiotic resistant bacteria and antibiotic resistant genes. To the best of our knowledge, no specific studies have considered how powdered activated carbon (PAC) treatments can act on antibiotic resistant bacteria, although it is essential to assess the impact of this wastewater treatment on the spread of antibiotic resistant bacteria. METHODS: To address this gap, we evaluated the fate and the distribution of fluorescent-tagged antibiotic/ antimycotic resistant microorganisms in a laboratory-scale model simulating a process configuration involving powdered activated carbon as advanced wastewater treatment. Furthermore, we studied the possible increase of naturally existing antibiotic resistant bacteria during the treatment implementing PAC recycling. RESULTS: The analysis of fluorescent-tagged microorganisms demonstrated the efficacy of the PAC adsorption treatment in reducing the load of both susceptible and resistant fluorescent microorganisms in the treated water, reaching a removal efficiency of 99.70%. Moreover, PAC recycling did not increase the resistance characteristics of cultivable bacteria neither in the sludge nor in the treated effluent. CONCLUSION: Results suggest that wastewater PAC treatment is a promising technology not only for the removal of micropollutants but also for its effect in decreasing antibiotic resistant bacteria release.201930727884
650010.9999Effect of ozonation-based disinfection methods on the removal of antibiotic resistant bacteria and resistance genes (ARB/ARGs) in water and wastewater treatment: a systematic review. Antibiotic resistance is considered a universal health threat of the 21st century which its distribution and even development are mainly mediated by water-based media. Disinfection processes with the conventional methods are still the most promising options to combat such crises in aqueous matrices especially wastewater. Knowing that the extent of effectiveness and quality of disinfection is of great importance, this paper aimed to systematically review and discuss ozonation (as one of the main disinfectants with large scale application) effect on removing antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from aqueous solutions, for which no study has been reported. For this, a comprehensive literature survey was performed within the international databases using appropriate keywords which yielded several studies involving different aspects and the effectiveness extent of ozonation on ARB & ARGs. The results showed that no definite conclusion could be drawn about the superiority of ozone alone or in a hybrid form. Mechanism of action was carefully evaluated and discussed although it is still poorly understood. Evaluation of the studies from denaturation and repairment perspectives showed that regrowth cannot be avoided after ozonation, especially for some ARB & ARGs variants. In addition, the comparison of the effectiveness on ARB & ARGs showed that ozonation is more effective for resistant bacteria than their respective genes. The degradation efficiency was found to be mainly influenced by operational parameters of CT (i.e. ozone dose & contact time), solids, alkalinity, pH, and type of pathogens and genes. Moreover, the correlation between ARB & ARGs removal and stressors (such as antibiotic residuals, heavy metals, aromatic matters, microcystins, opportunistic pathogens, etc.) has been reviewed to give the optimal references for further in-depth studies. The future perspectives have also been reported.202234767893
742420.9998Fate of antibiotic resistance genes and antibiotic-resistant bacteria in water resource recovery facilities. Many important diseases are showing resistance to commonly used antibiotics, and the resistance is potentially caused by widespread use of antibiotics for maintaining human health and improving food production. Antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) are associated with this increase, and their fate in water resource recovery facilities is an important, emerging area of research. This literature review summarizes current findings of worldwide research on the fate of ARB and ARGs in various types of treatment plants. Twenty-five published studies were reviewed which contained 215 observations in activated sludge, membrane bioreactors, anaerobic digestion, constructed wetlands, coagulation-filtration, and three types of disinfection. We found 70% decreased observations, 18% increased observations, and 12% unchanged observations of all observations in all treatment processes. Resistance genes to tetracycline were most often observed, but more studies are needed in other antibiotic resistance genes. The causes for increased abundance of ARGs and ARB are not well understood, and further studies are warranted. PRACTITIONER POINTS: Antibiotic resistance is increasing with concern that treatment plants may acclimate bacteria to antibiotics. A literature survey found 215 resistance observations with 70% decreased, 18% increased, 12% unchanged after treatment. The type of treatment process is important with activated sludge showing the greatest reductions.201930682226
649530.9998A Review on Occurrence and Spread of Antibiotic Resistance in Wastewaters and in Wastewater Treatment Plants: Mechanisms and Perspectives. This paper reviews current knowledge on sources, spread and removal mechanisms of antibiotic resistance genes (ARGs) in microbial communities of wastewaters, treatment plants and downstream recipients. Antibiotic is the most important tool to cure bacterial infections in humans and animals. The over- and misuse of antibiotics have played a major role in the development, spread, and prevalence of antibiotic resistance (AR) in the microbiomes of humans and animals, and microbial ecosystems worldwide. AR can be transferred and spread amongst bacteria via intra- and interspecies horizontal gene transfer (HGT). Wastewater treatment plants (WWTPs) receive wastewater containing an enormous variety of pollutants, including antibiotics, and chemicals from different sources. They contain large and diverse communities of microorganisms and provide a favorable environment for the spread and reproduction of AR. Existing WWTPs are not designed to remove micropollutants, antibiotic resistant bacteria (ARB) and ARGs, which therefore remain present in the effluent. Studies have shown that raw and treated wastewaters carry a higher amount of ARB in comparison to surface water, and such reports have led to further studies on more advanced treatment processes. This review summarizes what is known about AR removal efficiencies of different wastewater treatment methods, and it shows the variations among different methods. Results vary, but the trend is that conventional activated sludge treatment, with aerobic and/or anaerobic reactors alone or in series, followed by advanced post treatment methods like UV, ozonation, and oxidation removes considerably more ARGs and ARB than activated sludge treatment alone. In addition to AR levels in treated wastewater, it examines AR levels in biosolids, settled by-product from wastewater treatment, and discusses AR removal efficiency of different biosolids treatment procedures. Finally, it puts forward key-points and suggestions for dealing with and preventing further increase of AR in WWTPs and other aquatic environments, together with a discussion on the use of mathematical models to quantify and simulate the spread of ARGs in WWTPs. Mathematical models already play a role in the analysis and development of WWTPs, but they do not consider AR and challenges remain before models can be used to reliably study the dynamics and reduction of AR in such systems.202134707579
650140.9998Post-treatment disinfection technologies for sustainable removal of antibiotic residues and antimicrobial resistance bacteria from hospital wastewater. The World Health Organization (WHO) has identified antimicrobial resistance bacteria and its spread as one of the most serious threats to public health and the environment in the twenty-first century. Different treatment scenarios are found in several countries, each with their own regulations and selection criteria for the effluent quality and management practices of hospital wastewater. To prevent the spread of disease outbreaks and other environmental threats, the development of sustainable treatment techniques that remove all antibiotics and antimicrobial resistant bacteria and genes should be required. Although few research based articles published focusing this issues, explaining the drawbacks and effectiveness of post-treatment disinfection strategies for eliminating antibiotic residues and antimicrobial resistance from hospital wastewater is the reason of this review. The application of conventional activated sludge (CAS) in large scale hospital wastewater treatments poses high energy supply needs for aeration, capital and operational costs. Membrane bioreactors (MBR) have also progressively replaced the CAS treatment systems and achieved better treatment potential, but membrane fouling, energy cost for aeration, and membrane permeability loss restrict their performance at large scale operations. In addition, the membrane process alone doesn't completely remove/degrade these micropollutants; as a substitute, the pollutants are being concentrated in a smaller volume, which requires further post-treatment. Therefore, these drawbacks should be solved by developing advanced techniques to be integrated into any of these or other secondary wastewater treatment systems, aiming for the effective removal of these micropollutants. The purpose of this paper is to review the performances of post-treatment disinfection technologies in the removal of antibiotics, antimicrobial resistant bacteria and their gens from hospital wastewater. The performance of advanced disinfection technologies (such as granular and powered activated carbon adsorption, ozonation, UV, disinfections, phytoremediation), and other integrated post-treatment techniques are primarily reviewed. Besides, the ecotoxicology and public health risks of hospital wastewater, and the development, spreading and mechanisms of antimicrobial resistant and the protection of one health are also highlighted.202337123966
761050.9998Coagulation promotes the spread of antibiotic resistance genes in secondary effluents. Wastewater treatment plants (WWTPs) are biological hotspots receiving the residual antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) that greatly influence the spread of antibiotic resistance in the environment. A common method used in WWTPs for the purification of secondary effluent is coagulation. Notwithstanding the increasing health concern of antibiotic resistance in WWTPs, the impact of coagulation on the emergence and spread of antibiotic resistance remains unclear. To shed light on this, our study investigated the behavior of four representative ARB types (tetracycline, sulfamethoxazole, clindamycin, and ciprofloxacin resistance) during the coagulation process in a model wastewater treatment plant. Our search showed a significant reduction in the presence of ARBs after either PAC or FeCl(3) coagulation, with removal efficiencies of 95% and 90%, respectively. However, after 4 days of storage, ARB levels in the coagulated effluent increased by 6-138 times higher than the original secondary effluent. It suggests a potential resurgence and spread of antibiotic resistance after coagulation. Detailed studies suggest that coagulants, particularly PAC, may facilitate the transfer of ARGs among different bacterial species by the enhanced cell-cell contact during coagulation-induced bacterial aggregation. This transfer is further enhanced by the factors such as auxiliary mixing, longer incubation time and ideal operating temperatures. In addition, both PAC and FeCl(3) affected gene expression associated with bacterial conjugation, leading to an increase in conjugation efficiency. In conclusion, while coagulation serves as a purification method, it might inadvertently boost the spread of ARGs during tertiary wastewater treatment. This underscores the importance of implementing subsequent measures to mitigate this effect. Our findings provide a deeper understanding of the challenges posed by bacterial antibiotic resistance in wastewater and pave the way for devising more effective ARB and ARG management strategies.202438810683
649460.9998Performance Efficiency of Conventional Treatment Plants and Constructed Wetlands towards Reduction of Antibiotic Resistance. Domestic and industrial wastewater discharges harbor rich bacterial communities, including both pathogenic and commensal organisms that are antibiotic-resistant (AR). AR pathogens pose a potential threat to human and animal health. In wastewater treatment plants (WWTP), bacteria encounter environments suitable for horizontal gene transfer, providing an opportunity for bacterial cells to acquire new antibiotic-resistant genes. With many entry points to environmental components, especially water and soil, WWTPs are considered a critical control point for antibiotic resistance. The primary and secondary units of conventional WWTPs are not designed for the reduction of resistant microbes. Constructed wetlands (CWs) are viable wastewater treatment options with the potential for mitigating AR bacteria, their genes, pathogens, and general pollutants. Encouraging performance for the removal of AR (2-4 logs) has highlighted the applicability of CW on fields. Their low cost of construction, operation and maintenance makes them well suited for applications across the globe, especially in developing and low-income countries. The present review highlights a better understanding of the performance efficiency of conventional treatment plants and CWs for the elimination/reduction of AR from wastewater. They are viable alternatives that can be used for secondary/tertiary treatment or effluent polishing in combination with WWTP or in a decentralized manner.202235052991
760470.9998Combined applications of UV and chlorine on antibiotic resistance control: A critical review. Environmental health problems caused by antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) have become a global concern. ARB and ARGs have been continuously detected in various water environments, which pose a new challenge for water quality safety assurance. Disinfection is a key water treatment process to eliminate pathogenic microorganisms in water, and combined chlorine and UV processes (the UV/Cl(2) process, the UV-Cl(2) process, and the Cl(2)-UV process) are considered potential disinfection methods to control antibiotic resistance. This review documented the efficacy and mechanism of combined UV and chlorine processes for the control of antibiotic resistance, as well as the effects of chlorine dose, solution pH, UV wavelength, and water matrix on the effectiveness of the processes. There are knowledge gaps in research on the combined chlorine and UV processes for antibiotic resistance control, in particular the UV-Cl(2) process and the Cl(2)-UV process. In addition, changes in the structure of microbial communities and the distribution of ARGs, which are closely related to the spread of antibiotic resistance in the water, induced by combined processes were also addressed. Whether these changes could lead to the re-transmission of antibiotic resistance and harm human health may need to be further evaluated.202438072103
742580.9998Antibiotic 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
649990.9998From Conventional Disinfection to Antibiotic Resistance Control-Status of the Use of Chlorine and UV Irradiation during Wastewater Treatment. Extensive use of antibiotics for humans and livestock has led to an enhanced level of antibiotic resistance in the environment. Municipal wastewater treatment plants are regarded as one of the main sources of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the aquatic environment. A significant amount of research has been carried out to understand the microbiological quality of wastewater with respect to its antibiotic resistance potential over the past several years. UV disinfection has primarily been used to achieve disinfection, including damaging DNA, but there has been an increasing use of chlorine and H(2)O(2)-based AOPs for targeting genes, including ARGs, considering the higher energy demands related to the greater UV fluences needed to achieve efficient DNA damage. This review focuses on some of the most investigated processes, including UV photolysis and chlorine in both individual and combined approaches and UV advanced oxidation processes (AOPs) using H(2)O(2). Since these approaches have practical disinfection and wastewater treatment applications globally, the processes are reviewed from the perspective of extending their scope to DNA damage/ARG inactivation in full-scale wastewater treatment. The fate of ARGs during existing wastewater treatment processes and how it changes with existing treatment processes is reviewed with a view to highlighting the research needs in relation to selected processes for addressing future disinfection challenges.202235162659
6497100.9998Problems of conventional disinfection and new sterilization methods for antibiotic resistance control. The problem of bacterial antibiotic resistance has attracted considerable research attention, and the effects of water treatment on antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are being increasingly investigated. As an indispensable part of the water treatment process, disinfection plays an important role in controlling antibiotic resistance. At present, there were many studies on the effects of conventional and new sterilization methods on ARB and ARGs. However, there is a lack of literature relating to the limitations of conventional methods and analysis of new techniques. Therefore, this review focuses on analyzing the deficiencies of conventional disinfection and the development of new methods for antibiotic resistance control to guide future research. Firstly, we analyzed the effects and drawbacks of conventional disinfection methods, such as chlorine (Cl), ultraviolet (UV) and ozone on antibiotic resistance control. Secondly, we discuss the research progress and shortcomings of new sterilization methods in antibiotic resistance. Finally, we propose suggestions for future research directions. There is an urgent need for new effective and low-cost sterilization methods. Disinfection via UV and chlorine in combination, UV/chlorine showed greater potential for controlling ARGs.202032957272
6496110.9998Strategies to Combat Antibiotic Resistance in the Wastewater Treatment Plants. The main goal of this manuscript is to review different treatment strategies and mechanisms for combating the antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in the wastewater environment. The high amount of antibiotics is released into the wastewater that may promote selection of ARB and ARGs which find their way into natural environments. Emerging microbial pathogens and increasing antibiotic resistance among them is a global public health issue. The propagation and spread of ARB and ARGs in the environment may result in an increase of antibiotic resistant microbial pathogens which is a worldwide environmental and public health concern. A proper treatment of wastewater is essential before its discharge into rivers, lake, or sewage system to prevent the spread of ARB and ARGs into the environment. This review discusses various treatment options applied for combating the spread of ARB and ARGs in wastewater treatment plants (WWTPs). It was reported that low-energy anaerobic-aerobic treatment reactors, constructed wetlands, and disinfection processes have shown good removal efficiencies. Nanomaterials and biochar combined with other treatment methods and coagulation process are very recent strategies regarding ARB and ARGs removal and need more investigation and research. Based on current studies a wide-ranging removal efficiency of ARGs can be achieved depending on the type of genes present and treatment processes used, still, there are gaps that need to be further investigated. In order to find solutions to control dissemination of antibiotic resistance in the environment, it is important to (1) study innovative strategies in large scale and over a long time to reach an actual evaluation, (2) develop risk assessment studies to precisely understand occurrence and abundance of ARB/ARGs so that their potential risks to human health can be determined, and (3) consider operating and environmental factors that affect the efficiency of each treatment mechanism.201729387043
6493120.9998Antibiotic microbial resistance (AMR) removal efficiencies by conventional and advanced wastewater treatment processes: A review. The World Health Organization (WHO) has identified the spread of antibiotic resistance as one of the major risks to global public health. An important transfer route into the aquatic environment is the urban water cycle. In this paper the occurrence and transport of antibiotic microbial resistance in the urban water cycle are critically reviewed. The presence of antibiotic resistance in low impacted surface water is being discussed to determine background antibiotic resistance levels, which might serve as a reference for treatment targets in the absence of health-based threshold levels. Different biological, physical and disinfection/oxidation processes employed in wastewater treatment and their efficacy regarding their removal of antibiotic resistant bacteria and antibiotic resistance geness (ARGs) were evaluated. A more efficient removal of antibiotic microbial resistance abundances from wastewater effluents can be achieved by advanced treatment processes, including membrane filtration, ozonation, UV-irradiation or chlorination, to levels typically observed in urban surface water or low impacted surface water.201931195321
6503130.9998The role of operating parameters and oxidative damage mechanisms of advanced chemical oxidation processes in the combat against antibiotic-resistant bacteria and resistance genes present in urban wastewater. An upsurge in the study of antibiotic resistance in the environment has been observed in the last decade. Nowadays, it is becoming increasingly clear that urban wastewater is a key source of antibiotic resistance determinants, i.e. antibiotic-resistant bacteria and antibiotic resistance genes (ARB&ARGs). Urban wastewater reuse has arisen as an important component of water resources management in the European Union and worldwide to address prolonged water scarcity issues. Especially, biological wastewater treatment processes (i.e. conventional activated sludge), which are widely applied in urban wastewater treatment plants, have been shown to provide an ideal environment for the evolution and spread of antibiotic resistance. The ability of advanced chemical oxidation processes (AOPs), e.g. light-driven oxidation in the presence of H(2)O(2), ozonation, homogeneous and heterogeneous photocatalysis, to inactivate ARB and remove ARGs in wastewater effluents has not been yet evaluated through a systematic and integrated approach. Consequently, this review seeks to provide an extensive and critical appraisal on the assessment of the efficiency of these processes in inactivating ARB and removing ARGs in wastewater effluents, based on recent available scientific literature. It tries to elucidate how the key operating conditions may affect the process efficiency, while pinpointing potential areas for further research and major knowledge gaps which need to be addressed. Also, this review aims at shedding light on the main oxidative damage pathways involved in the inactivation of ARB and removal of ARGs by these processes. In general, the lack and/or heterogeneity of the available scientific data, as well as the different methodological approaches applied in the various studies, make difficult the accurate evaluation of the efficiency of the processes applied. Besides the operating conditions, the variable behavior observed by the various examined genetic constituents of the microbial community, may be directed by the process distinct oxidative damage mechanisms in place during the application of each treatment technology. For example, it was shown in various studies that the majority of cellular damage by advanced chemical oxidation may be on cell wall and membrane structures of the targeted bacteria, leaving the internal components of the cells relatively intact/able to repair damage. As a result, further in-depth mechanistic studies are required, to establish the optimum operating conditions under which oxidative mechanisms target internal cell components such as genetic material and ribosomal structures more intensively, thus conferring permanent damage and/or death and preventing potential post-treatment re-growth.201829153875
7603140.9998Antibiotic enhances the spread of antibiotic resistance among chlorine-resistant bacteria in drinking water distribution system. The extensive use of antibiotics leads to the occurrences of antibiotic resistance genes (ARGs) in aquatic environment. As an emerging environmental pollutant, its pollution in aquatic environment has aroused widespread concern. However, the residues of antibiotics and antibiotic resistance genes in drinking water distribution system were barely reported up to now. Here, we studied the correlation and coordination between chlorine resistance mechanism and antibiotic resistance mechanism of chlorine-resistant bacteria. Antibiotics induce the resistance of chlorine-resistant bacteria (CRB) to NaClO, so that low-dose disinfectants can not inactivate CRB. We put forward a strategy to control the growth of CRB by controlling the concentration of biodegradable dissolved organic carbon (BDOC) in the front section of the water network. Moreover, We screened two strains of chlorine-resistant bacteria with different antibiotic resistance after mixed culture, the results showed that antibiotic resistance could spread horizontally among different kinds of bacteria. Then, the non-pathogenic bacteria can be used as a carrier, causing the pathogen to become resistant to antibiotic, and ultimately pose harm to human health. Generally, the antibiotic, antibiotic resistant genes, and the chlorine disinfectants added in water treatment plants will interact with bacteria in the water supply pipe network, which causes pollution to drinking water.202235248560
7442150.9998Potential impacts of disinfection processes on elimination and deactivation of antibiotic resistance genes during water and wastewater treatment. Antibiotic resistance genes (ARGs), in association with antibiotic resistant bacteria (ARB), have been identified as widespread contaminants of treated drinking waters and wastewaters. As a consequence, concerns have been raised that ARB or ARG transport between aquatic compartments may enhance the spread of antibiotic resistance amongst non-resistant bacterial communities by means of horizontal gene transfer processes. Most often, discussion of horizontal gene transfer focuses on the probable role of conjugative plasmid or transposon exchange, which requires live ARB donor cells. Conventional water and wastewater disinfection processes generally provide highly effective means for mitigating the transport of live ARB; thereby minimizing risks of conjugative gene transfer. However, even if ARB present in a treated water are fully inactivated during a disinfection process, the possibility remains that intact remnants of DNA contained within the resulting cell debris could still confer resistance genotypes to downstream bacterial populations by means of natural transformation and/or transduction, which do not require live donor cells. Thus, a systematic evaluation of the capability of common disinfection technologies to ensure the destruction of bacterial DNA, in addition to pathogen inactivation, seems warranted. With that objective in mind, this review seeks to provide a concise introduction to the significance of ARB and ARG occurrence in environmental systems, coupled with a review of the role that commonly used water and wastewater disinfection processes may play in minimizing ARG transport and dissemination.201222572858
6491160.9998Nature-based bioreactors: Tackling antibiotic resistance in urban wastewater treatment. The overuse and misuse of antibiotics have accelerated the selection of antibiotic-resistant bacteria, significantly impacting human, animal, and environmental health. As aquatic environments are vulnerable to antibiotic resistance, suitable management practices should be adopted to tackle this phenomenon. Here we show an effective, nature-based solution for reducing antibiotic resistance from actual wastewater. We utilize a bioreactor that relies on benthic (biofilms) and planktonic microbial communities to treat secondary effluent from a small urban wastewater treatment plant (<10,000 population equivalent). This treated effluent is eventually released into the local aquatic ecosystem. We observe high removal efficiency for genes that provide resistance to commonly used antibiotic families, as well as for mobile genetic elements that could potentially aid in their spread. Importantly, we notice a buildup of sulfonamide (sul1 and sul2) and tetracycline (tet(C), tet(G), and tetR) resistance genes specifically in biofilms. This advancement marks the initial step in considering this bioreactor as a nature-based, cost-effective tertiary treatment option for small UWWTPs facing antibiotic resistance challenges.202439055482
6498170.9998Does light-based tertiary treatment prevent the spread of antibiotic resistance genes? Performance, regrowth and future direction. The common occurrence of antibiotic-resistance genes (ARGs) originating from pathogenic and facultative pathogenic bacteria pose a high risk to aquatic environments. Low removal of ARGs in conventional wastewater treatment processes and horizontal dissemination of resistance genes between environmental bacteria and human pathogens have made antibiotic resistance evolution a complex global health issue. The phenomenon of regrowth of bacteria after disinfection raised some concerns regarding the long-lasting safety of treated waters. Despite the inactivation of living antibiotic-resistant bacteria (ARB), the possibility of transferring intact and liberated DNA containing ARGs remains. A step in this direction would be to apply new types of disinfection methods addressing this issue in detail, such as light-based advanced oxidation, that potentially enhance the effect of direct light interaction with DNA. This study is devoted to comprehensively and critically review the current state-of-art for light-driven disinfection. The main focus of the article is to provide an insight into the different photochemical disinfection methods currently being studied worldwide with respect to ARGs removal as an alternative to conventional methods. The systematic comparison of UV/chlorination, UV/H(2)O(2), sulfate radical based-AOPs, photocatalytic processes and photoFenton considering their mode of action on molecular level, operational parameters of the processes, and overall efficiency of removal of ARGs is presented. An in-depth discussion of different light-dependent inactivation pathways, influence of DBP and DOM on ARG removal and the potential bacterial regrowth after treatment is presented. Based on presented revision the risk of ARG transfer from reactivated bacteria has been evaluated, leading to a future direction for research addressing the challenges of light-based disinfection technologies.202235031375
7510180.9997Impacts of antibiotics on biofilm bacterial community and disinfection performance on simulated drinking water supply pipe wall. Overuse of antibiotics is accelerating the spread of resistance risk in the environment. In drinking water supply systems, the effect of antibiotics on the resistance of biofilm is unclear, and there have been few studies in disinfectant-containing systems. Here, we designed a series of drinking water supply reactors to investigate the effects of antibiotics on biofilm and bacteria in the water. At low concentrations, antibiotics could promote the growth of bacteria in biofilm; among the tested antibiotics (tetracycline, sulfadiazine and chloramphenicol), tetracycline had the strongest ability to promote this. And the antibiotic resistant bacteria (ARB) could inhibit the growth of bacteria in drinking water. Results have shown that antibiotics enhanced the bacterial chlorine resistance in the effluent, but reduced that in the biofilm. Furthermore, metagenomic analysis showed that antibiotics reduced the richness of biofilm communities. The dominant phyla in the biofilm were Proteobacteria, Planctomycetes, and Firmicutes. In tetracycline-treated biofilm, the dominant phylum was Planctomycetes. In sulfadiazine- and chloramphenicol-treated groups, bacteria with complex cell structures preferentially accumulated. The dominant class in biofilm in the ARB-added group was Gammaproteobacteria. The abundance of antibiotic resistant genes (ARGs) was correlated with biofilm community structure. This study shows that antibiotics make the biofilm community structure of drinking water more resistant to chlorine. ARGs may be selective for certain bacteria in the process, and there may ultimately be enhanced chlorine and antibiotic resistance of effluent bacteria in drinking water.202134256291
6479190.9997Fate and transport of antibiotic residues and antibiotic resistance genes following land application of manure waste. Antibiotics are used in animal livestock production for therapeutic treatment of disease and at subtherapeutic levels for growth promotion and improvement of feed efficiency. It is estimated that approximately 75% of antibiotics are not absorbed by animals and are excreted in waste. Antibiotic resistance selection occurs among gastrointestinal bacteria, which are also excreted in manure and stored in waste holding systems. Land application of animal waste is a common disposal method used in the United States and is a means for environmental entry of both antibiotics and genetic resistance determinants. Concerns for bacterial resistance gene selection and dissemination of resistance genes have prompted interest about the concentrations and biological activity of drug residues and break-down metabolites, and their fate and transport. Fecal bacteria can survive for weeks to months in the environment, depending on species and temperature, however, genetic elements can persist regardless of cell viability. Phylogenetic analyses indicate antibiotic resistance genes have evolved, although some genes have been maintained in bacteria before the modern antibiotic era. Quantitative measurements of drug residues and levels of resistance genes are needed, in addition to understanding the environmental mechanisms of genetic selection, gene acquisition, and the spatiotemporal dynamics of these resistance genes and their bacterial hosts. This review article discusses an accumulation of findings that address aspects of the fate, transport, and persistence of antibiotics and antibiotic resistance genes in natural environments, with emphasis on mechanisms pertaining to soil environments following land application of animal waste effluent.200919398507