Efficient inactivation of antibiotic resistant bacteria and antibiotic resistance genes by photo-Fenton process under visible LED light and neutral pH. - Related Documents




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782101.0000Efficient inactivation of antibiotic resistant bacteria and antibiotic resistance genes by photo-Fenton process under visible LED light and neutral pH. Antibiotic resistance has been recognized as a major threat to public health worldwide. Inactivation of antibiotic resistant bacteria (ARB) and degradation of antibiotic resistance genes (ARGs) are critical to prevent the spread of antibiotic resistance in the environment. Conventional disinfection processes are effective to inactivate water-borne pathogens, yet they are unable to completely eliminate the antibiotic resistance risk. This study explored the potential of the photo-Fenton process to inactivate ARB, and to degrade both extracellular and intracellular ARGs (e-ARGs and i-ARGs, respectively). Using Escherichia coli DH5α with two plasmid-encoded ARGs (tetA and bla(TEM)(-1)) as a model ARB, a 6.17 log ARB removal was achieved within 30 min of applying photo-Fenton under visible LED and neutral pH conditions. In addition, no ARB regrowth occurred after 48-h, demonstrating that this process is very effective to induce permanent disinfection on ARB. The photo-Fenton process was validated under various water matrices, including ultrapure water (UPW), simulated wastewater (SWW) and phosphate buffer (PBS). The higher inactivation efficiency was observed in SWW as compared to other matrices. The photo-Fenton process also caused a 6.75 to 8.56-log reduction in eARGs based on quantitative real-time PCR of both short- and long amplicons. Atomic force microscopy (AFM) further confirmed that the extracellular DNA was sheared into short DNA fragments, thus eliminating the risk of the transmission of antibiotic resistance. As compared with e-ARGs, a higher dosage of Fenton reagent was required to damage i-ARGs. In addition, the tetA gene was more easily degraded than the bla(TEM)(-1) gene. Collectively, our results demonstrate the photo-Fenton process is a promising technology for disinfecting water to prevent the spread of antibiotic resistance.202032417561
782210.9998Solar photo-Fenton disinfection of 11 antibiotic-resistant bacteria (ARB) and elimination of representative AR genes. Evidence that antibiotic resistance does not imply resistance to oxidative treatment. The emergence of antibiotic resistance represents a major threat to human health. In this work we investigated the elimination of antibiotic resistant bacteria (ARB) by solar light and solar photo-Fenton processes. As such, we have designed an experimental plan in which several bacterial strains (Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae) possessing different drug-susceptible and -resistant patterns and structures (Gram-positive and Gram-negative) were subjected to solar light and the photo-Fenton oxidative treatment in water. We showed that both solar light and solar photo-Fenton processes were effective in the elimination of ARB in water and that the time necessary for solar light disinfection and solar photo-Fenton disinfection were similar for antibiotic-susceptible and antibiotic-resistant strains (mostly 180-240 and 90-120 min, respectively). Moreover, the bacterial structure did not significantly affect the effectiveness of the treatment. Similar regrowth pattern was observed (compared to the susceptible strain) and no development of bacteria with higher drug-resistance values was found in waters after any treatment. Finally, both processes were effective to reduce AR genes (ARGs), although solar photo-Fenton was more rapid than solar light. In conclusion, the solar photo-Fenton process ensured effective disinfection of ARB and elimination of ARGs in water (or wastewater) and is a potential mean to ensure limitation of ARB and ARG spread in nature.201829986243
757120.9998Ancient Oriental Wisdom still Works: Removing ARGs in Drinking Water by Boiling as compared to Chlorination. Antibiotic resistance genes (ARGs) in municipal drinking water may not be effectively removed during centralized treatment. To reduce potential health risks, water disinfection at the point-of-use scale is warranted. This study investigated the performance of boiling, a prevalent household water disinfection means, in response to ARGs contamination. We found that boiling was more efficient in inactivating both Escherichia coli and environmental bacteria compared to chlorination and pasteurization. Boiling of environmental bacteria suspension removed a much broader spectrum of ARGs and mobile genetic elements (up to 141 genes) than chlorination (up to 13 genes), such better performance was largely attributed to a stronger inactivation of chlorine-tolerant bacteria including Acinetobacter and Bacillus. Accumulation of extracellular ARGs was found during low-temperature heating (≤ 80°C) and in the initial stage of chlorination (first 3 min when initial chlorine was 5 mg/L and first 12 min when initial chlorine was 1 mg/L). These extracellular ARGs as well as the intracellular ARGs got removed as the heating temperature increased or the chlorination time prolonged. Under the same treatment time (30 min), high-temperature heating (≥ 90.1°C) damaged the DNA structure more thoroughly than chlorination (5 mg/L). Taking into account the low transferability of ARGs after DNA melting, boiling may provide an effective point-of-use approach to attenuating bacterial ARGs in drinking water and is still worth promoting in the future.202234910990
784530.9998Mechanism and potential risk of antibiotic resistant bacteria carrying last resort antibiotic resistance genes under electrochemical treatment. The significant rise in the number of antibiotic resistance genes (ARGs) that resulted from our abuse of antibiotics could do severe harm to public health as well as to the environment. We investigated removal efficiency and removal mechanism of electrochemical (EC) treatment based on 6 different bacteria isolated from hospital wastewater carrying 3 last resort ARGs including NDM-1, mcr-1 and tetX respectively. We found that the removal efficiency of ARGs increased with the increase of both voltage and electrolysis time while the maximum removal efficiency can reach 90%. The optimal treatment voltage and treatment time were 3 V and 120 min, respectively. Temperature, pH and other factors had little influence on the EC treatment process. The mechanism of EC treatment was explored from the macroscopic and microscopic levels by scanning electron microscopy (SEM) and flow cytometry. Our results showed that EC treatment significantly changed the permeability of cell membrane and caused cells successively experience early cell apoptosis, late cell apoptosis and cell necrosis. Moreover, compared with traditional disinfection methods, EC treatment had less potential risks. The conjugative transfer frequencies of cells were significantly reduced after treatment. Less than 1% of bacteria entered the viable but nonculturable (VBNC) state and less than 5% of intracellular ARGs (iARGs) turned into extracellular ARGs (eARGs). Our findings provide new insights into as well as important reference for future electrochemical treatment in removing ARB from hospital wastewater.202235085630
784740.9998Inactivation and change of tetracycline-resistant Escherichia coli in secondary effluent by visible light-driven photocatalytic process using Ag/AgBr/g-C(3)N(4). Control of antibiotic-resistant bacteria (ARB) and their related genes in secondary effluents has become a serious issue because of increased awareness of their health risks. A considerable number of techniques have been developed in recent years, particularly in relation to advanced oxidation. However, limited information is known about cellular behavior and resistance characteristic change during photocatalytic treatment. In this study, the inactivation of tetracycline (TC)-resistant Escherichia coli (TC-E. coli), removal of TC-resistant genes (TC-RGs), and antibiotic susceptibility were evaluated by employing photocatalytic treatment using Ag/AgBr/g-C(3)N(4) with visible light irradiation. The effects of light intensity, photocatalyst dosage, and reaction ambient temperature on photocatalysis were modelled and investigated. The rate of TC-E. coli removal was also optimized. Results demonstrated that the optimal conditions for TC-E. coli removal included light intensity of 96.0 mW/cm(2), photocatalyst dosage of 211.0 mg/L, and reaction ambient temperature of 23.7 °C. Under such conditions, the ARB removal rate was 6.1 log after 90 min and the related TC-RG removal rates were 49%, 86%, 69%, and 86% for tetA, tetM, tetQ, and intl1, respectively. The minimum inhibitory concentration test after photocatalysis shows that the antibiotic resistance of TC-E. coli was enhanced, which may be mainly due to the changes in the membrane potential and resulted in difficulty in destroying the bacteria through antibiotic contact. Hence, photocatalytic treatment could be an ideal method for ARB and antibiotic-resistant gene (ARG) control in wastewater, but the health risks of the remaining ARB and ARG should be investigated further.202031841919
784450.9998Insight into using a novel ultraviolet/peracetic acid combination disinfection process to simultaneously remove antibiotics and antibiotic resistance genes in wastewater: Mechanism and comparison with conventional processes. In this study, the simultaneous removal mechanism of antibiotics and antibiotic resistance genes (ARGs) was investigated using the novel ultraviolet/peracetic acid (UV/PAA) combination disinfection process and conventional disinfection processes were also applied for comparison. The results showed that UV/PAA disinfection with a high UV dosage (UV/PAA-H) was most effective for the removal of tetracyclines, quinolones, macrolides and β-lactams; their average removal efficiencies ranged from 25.7% to 100%, while NaClO disinfection was effective for the removal of sulfonamides (∼81.6%). The majority of ARGs were well removed after the UV/PAA-H disinfection, while specific genes including tetB, tetC, ermA and bla(TEM) significantly increased after NaClO disinfection. In addition, β-lactam resistance genes (-35.9%) and macrolides resistance genes (-12.0%) remarkably augmented after UV/NaClO disinfection. The highly reactive oxidation species generated from UV/PAA process including hydroxyl radicals (•OH) and carbon-centered organic radicals (R-C•), were responsible for the elimination of antibiotics and ARGs. Correlation analysis showed that tetracycline, sulfonamide and macrolide antibiotics removal showed a positive correlation with the corresponding ARGs, and a low dose of antibiotic residues played an important role in the distribution of ARGs. Metagenomic sequencing analysis showed that UV/PAA disinfection could not only greatly decrease the abundance of resistant bacteria but also downregulate the expression of key functional genes involved in ARGs propagation and inhibit the signal transduction of the host bacteria, underlying that its removal mechanism was quite different from that of NaClO-based disinfection processes. Our study provides valuable information for understanding the simultaneous removal mechanism of antibiotics and ARGs in wastewater during the disinfection processes, especially for the novel UV/PAA combination process.202234982977
850160.9997Mechanistic insight of simultaneous removal of tetracycline and its related antibiotic resistance bacteria and genes by ferrate(VI). The emergence of antibiotics and their corresponding antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have posed great challenges to the public health. The paper demonstrates the removal of co-existing tetracycline (TC), its resistant Escherichia coli (E. coli), and ARGs (tetA and tetR) in a mixed system by applying ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) at pH 7.0. TC was efficiently degraded by Fe(VI), and the rapid inactivation of the resistant E. coli was found with the complete loss of culturability. The results of flow cytometry suggested that the damage of membrane integrity and respiratory activity were highly correlated with the Fe(VI) dosages. Moreover, high-dose Fe(VI) eliminates 6 log(10) viable but non-culturable (VBNC) cells and even breaks the cells into fragments. ARGs in extracellular form (e-ARGs) exhibited a high sensitivity of 4.44 log(10) removal to Fe(VI). Comparatively, no removal of intracellular ARGs (i-ARGs) was observed due to the multi-protection of cellular structure and rapid decay of Fe(VI). The oxidized products of TC were assessed to be less toxic than the parent compound. Overall, this study demonstrated the superior efficiency and great promise of Fe(VI) on simultaneous removal of antibiotics and their related ARB and ARGs in water.202133984704
780670.9997Electrocatalytic inactivation of antibiotic resistant bacteria and control of antibiotic resistance dissemination risk. Antibiotic resistance in environmental matrices becomes urgently significant for public health and has been considered as an emerging environmental contaminant. In this work, the ampicillin-resistant Escherichia coli (AR E. coli) and corresponding resistance genes (bla(TEM-1)) were effectively eliminated by the electrocatalytic process, and the dissemination risk of antibiotic resistance was also investigated. All the AR E. coli (∼8 log) was inactivated and 8.17 log bla(TEM-1) was degraded by the carbon nanotubes/agarose/titanium (CNTs/AG/Ti) electrode within 30 min. AR E. coli was inactivated mainly attributing to the damage of cell membrane, which was attacked by reactive oxygen species and subsequent leakage of intracellular cytoplasm. The bla(TEM-1) was degraded owing to the strand breaking in the process of electrocatalytic degradation. Furthermore, the dissemination risk of antibiotic resistance was effectively controlled after being electrocatalytic treatment. This study provided an effective electrocatalytic technology for the inactivation of antibiotic resistant bacteria and control of antibiotic resistance dissemination risk in the aqueous environment.202134543954
780780.9997Copper oxide/peroxydisulfate system for urban wastewater disinfection: Performances, reactive species, and antibiotic resistance genes removal. In this study, copper oxide (CuO) catalyzed peroxydisulfate (PDS) system was investigated for the inactivation of a broad range of pathogenic microorganisms from urban wastewater. Complete inactivation of Escherichia coli, Enterococcus, F-specific RNA bacteriophages from secondary treated wastewater was achieved after a short time (15-30 min) treatment with CuO (10 g/L)/PDS (1 mM) system, but spores of sulfite-reducing bacteria took 120 min. No bacterial regrowth occurred during storage after treatment. Significant reduction of the pathogens was explained by the generation of the highly selective Cu(III) oxidant, as the predominant reactive species, which could quickly oxidize guanine through a one-electron oxidation pathway. Additionally, the potential of the CuO (10 g/L)/PDS (1 mM) system to inactivate antibiotic-resistant bacteria and antibiotic resistance genes (ARB&Gs) was explored. Sulfamethoxazole-resistant E. coli was used as the model ARB and a 3.2 log of reduction was observed after 10 min of treatment. A considerable reduction (0.7-2.3 log) of selected ARGs including blaTEM, qnrS, emrB, sul1, and genes related to the dissemination of antibiotic resistance, including the Class 1 integron-integrase (intI1), and the insertion sequence (IS613) was achieved after 60 min treatment. All these findings indicated the promising applicability of the CuO/PDS system as a disinfection technology for wastewater reuse in agriculture.202234648831
784990.9997Efficient removal of antibiotic-resistant bacteria and intracellular antibiotic resistance genes by heterogeneous activation of peroxymonosulfate on hierarchical macro-mesoporous Co(3)O(4)-SiO(2) with enhanced photogenerated charges. Antibiotic resistance genes (ARGs) and their host antibiotic-resistant bacteria (ARB) are widely detected in the environment and pose a threat to human health. Traditional disinfection in water treatment plants cannot effectively remove ARGs and ARB. This study explored the potential of a heterogeneous photo-Fenton-like process utilizing a hierarchical macro-mesoporous Co(3)O(4)-SiO(2) (MM CS) catalyst for activation of peroxymonosulfate (PMS) to inactivate ARB and degrade the intracellular ARGs. A typical gram-negative antibiotic-resistant bacteria called Pseudomonas sp. HLS-6 was used as a model ARB. A completed inactivation of ARB at ∼10(7) CFU/mL was achieved in 30 s, and an efficient removal rate of more than 4.0 log for specific ARGs (sul1 and intI1) was achieved within 60 min by the MM CS-based heterogeneous photo-Fenton-like process under visible light and neutral pH conditions. Mechanism investigation revealed that •O(2)(-) and (1)O(2) were the vital reactive species for ARB inactivation and ARG degradation. The formation and transformation of the active species were proposed. Furthermore, the hierarchical macro-mesoporous structure of MM CS provided excellent optical and photoelectrochemical properties that promoted the cycle of Co(3+)/Co(2+) and the effective utilization of PMS. This process was validated to be effective in various water matrices, including deionized water, underground water, source water, and secondary effluent wastewater. Collectively, this work demonstrated that the MM CS-based heterogeneous photo-Fenton-like process is a promising technology for controlling the spread of antibiotic resistance in aquatic environments.202235149504
7840100.9997Ferrate(VI) promotes inactivation of antibiotic-resistant bacteria and chlorine-resistant bacteria in water. The increasing problem of antibiotic resistance has garnered significant global attention. As a novel water treatment agent with strong oxidizing, disinfecting, and bactericidal properties, ferrate(VI) holds promise for inactivating antibiotic-resistant bacteria (ARB) and chlorine-resistant bacteria. The results showed that complete inactivation of ARB (10⁵ CFU/mL) was achieved when the ferrate(VI) concentration was 10 μM and the treatment duration was 5 min. For higher concentrations of ARB (10(8) CFU/mL), it was also possible to reduce the concentration by 1.73 log units. The concentration of Acinetobacter baylyi ADP1 was also reduced by 1.77 log units. Additionally, the absolute abundance of antibiotic resistance genes (ARGs), including aphA, bla(TEM), and tetA, was significantly reduced. Ferrate(VI) was rapidly consumed in the early stages of treatment, undergoing a stepwise reduction process that generated high-valent Fe intermediates and reactive oxygen species (ROS), both of which contributed to bacterial inactivation. Throughout the reaction, •O(2)(-) played a dominant role in bacterial inactivation, with H₂O₂ acting synergistically and •OH contributing at later stages, leading to ROS overload, severe cellular damage, and enhanced membrane disruption. This study confirmed that ferrate(VI) could effectively inactivate ARB and chlorine-tolerant bacteria, and reduce the abundances of ARGs.202540245720
7605110.9997Inactivation of antibiotic resistant bacteria and their resistance genes in sewage by applying pulsed electric fields. We evaluated the suitability of pulsed electric field (PEF) technology as a new disinfection option in the sewage treatment plants (STPs) that can inactivate antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). It was shown that PEF applied disinfection could inactivate not only vancomycin-resistant enterococci (VRE), but also vanA resistance gene. Cultivable VRE could be effectively inactivated by PEF applied disinfection, and were reduced to below the detection limit (log reduction value of VRE > 5 log). Although the vanA also showed a reduction of more than 4 log, it remained in the order of 10(5) copies/mL, suggesting that ARGs are more difficult to be inactivated than ARB in PEF applied disinfection. Among parameters in each applying condition verified in this study, the initial voltage was found to be the most important for inactivation of ARB and ARGs. Furthermore, frequency was a parameter that affects the increase or decrease of the duration time, and it was suggested that the treatment time could be shortened by increasing the frequency. Our results strongly suggested that PEF applied disinfection may be a new disinfection technology option for STPs that contributes to the control of ARB and ARGs contamination in the aquatic environments.202234879573
7601120.9997Evaluating the Impact of Cl(2)(•-) Generation on Antibiotic-Resistance Contamination Removal via UV/Peroxydisulfate. The removal of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) using sulfate anion radical (SO(4)(•-))-based advanced oxidation processes has gained considerable attention recently. However, immense uncertainties persist in technology transfer. Particularly, the impact of dichlorine radical (Cl(2)(•-)) generation during SO(4)(•-)-mediated disinfection on ARB/ARGs removal remains unclear, despite the Cl(2)(•-) concentration reaching levels notably higher than those of SO(4)(•-) in certain SO(4)(•-)-based procedures applied to secondary effluents, hospital wastewaters, and marine waters. The experimental results of this study reveal a detrimental effect on the disinfection efficiency of tetracycline-resistant Escherichia coli (Tc-ARB) during SO(4)(•-)-mediated treatment owing to Cl(2)(•-) generation. Through a comparative investigation of the distinct inactivation mechanisms of Tc-ARB in the Cl(2)(•-)- and SO(4)(•-)-mediated disinfection processes, encompassing various perspectives, we confirm that Cl(2)(•-) is less effective in inducing cellular structural damage, perturbing cellular metabolic activity, disrupting antioxidant enzyme system, damaging genetic material, and inducing the viable but nonculturable state. Consequently, this diminishes the disinfection efficiency of SO(4)(•-)-mediated treatment owing to Cl(2)(•-) generation. Importantly, the results indicate that Cl(2)(•-) generation increases the potential risk associated with the dark reactivation of Tc-ARB and the vertical gene transfer process of tetracycline-resistant genes following SO(4)(•-)-mediated disinfection. This study underscores the undesired role of Cl(2)(•-) for ARB/ARGs removal during the SO(4)(•-)-mediated disinfection process.202438477971
7846130.9997Removal of antibiotic resistance genes and inactivation of antibiotic-resistant bacteria by oxidative treatments. The persistence of antibiotics in the environment because of human activities, such as seafood cultivation, has attracted great attention as they can give rise to antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). In this study, we explored the inactivation and removal efficiencies of Escherichia coli SR1 and sul1 (plasmid-encoded ARGs), respectively, in their extracellular and intracellular forms (eARGs and iARGs) by three commonly used fishery oxidants, namely chlorine, bromine, and potassium permanganate (KMnO(4)), at the practical effective concentration range (0.5, 5, and 15 mg/L). Kinetics data were obtained using laboratory phosphate-buffered saline (PBS). Following the same fishery oxidation methods, the determined kinetics models were tested by studying the SR1 and sul1 disinfection efficiencies in (sterilized) pond water matrix. At concentrations of 5 and 15 mg/L, all three oxidants achieved sufficient cumulative integrated exposure (CT values) to completely inactivate SR1 and efficiently remove sul1 (up to 4.0-log). The oxidation methods were then applied to an unsterilized pond water matrix in order to study and evaluate the indigenous ARB and ARGs disinfection efficiencies in aquaculture, which reached 1.4-log and 1.0-log during treatment with fishery oxidants used in pond preparation at high concentrations before stocking (5-15 mg/L), respectively. A high chlorine concentration (15 mg/L) could efficiently remove ARGs (or iARGs) from pond water, and the iARG removal efficiency was higher than that of eARGs in pond water. The method and results of this study could aid in guiding future research and practical disinfection to control the spread of ARGs and ARB in aquaculture.202134030387
7838140.9997Impacts on antibiotic-resistant bacteria and their horizontal gene transfer by graphene-based TiO(2)&Ag composite photocatalysts under solar irradiation. In recent years, photocatalysis has been considered as a promising method, which provides measures to environmental pollution. Antibiotic resistant bacteria (ARB) and their antibiotic resistance genes (ARGs), as the emerging environmental pollutants, are released into the environment, resulting in antibiotic resistance spread. TiO(2)-based nanocomposites, as the most common photocatalytic material, may influence ARB and ARGs under photocatalytic conditions. However, the research on this aspect is rare. A novel nanocomposite synthesized from Ag, TiO(2) and graphene oxide (GO), was selected as a representative of nanomaterials for investigation. The experimental results indicated that TiO(2)/Ag/GO nanocomposites significantly affected ARB vitality. 100 mg/L TiO(2)/Ag/GO will reduce bacterial survival to 12.2% in 10 min under simulated sunlight irradiation. Chloramphenicol as the most representative antibiotic in the water, reduces the effect of ARB inactivation under photocatalytic conditions. The addition of TiO(2)/Ag/GO could affect tetracycline antibiotic resistance. The level of bacterial tolerance to tetracycline had a significant reduction. The horizontal gene transfer was promoted from 1 to 2 folds with the addition of TiO(2)/Ag/GO. Even high TiO(2)/Ag/GO concentration (100 mg/L) sample had a limited promotion, suggesting that TiO(2)/Ag/GO will not increase the risk of antibiotic resistance spread compared to other nano materials.201931330386
8500150.9997Plasma induced efficient removal of antibiotic-resistant Escherichia coli and antibiotic resistance genes, and inhibition of gene transfer by conjugation. Antibiotic-resistant bacteria (ARB) and their resistance genes (ARGs) are emerging environmental pollutants that pose great threats to human health. In this study, a novel strategy using plasma was developed to simultaneously remove antibiotic-resistant Escherichia coli (AR bio-56954 E. coli) and its ARGs, aiming to inhibit gene transfer by conjugation. Approximately 6.6 log AR bio-56954 E. coli was inactivated within 10 min plasma treatment, and the antibiotic resistance to tested antibiotics (tetracycline, gentamicin, and amoxicillin) significantly decreased. Reactive oxygen and nitrogen species (RONS) including •OH, (1)O(2), O(2)•(-), NO(2)(-), and NO(3)(-) contributed to ARB and ARGs elimination; their attacks led to destruction of cell membrane, accumulation of excessive intracellular reactive oxygen substances, deterioration of conformational structures of proteins, and destroy of nucleotide bases of DNA. As a result, the ARGs (tet(C), tet(W), blaTEM-1, aac(3)-II), and integron gene intI1), and conjugative transfer frequency of ARGs significantly decreased after plasma treatment. The results demonstrated that plasma has great prospective application in removing ARB and ARGs in water, inhibiting gene transfer by conjugation.202134214852
7827160.9997Inactivation of antibiotic-resistant bacteria and antibiotic resistance genes by electrochemical oxidation/electro-Fenton process. Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment are of great concern due to their potential risk to human health. The effluents from wastewater treatment plants and livestock production are major sources of ARB and ARGs. Chlorination, UV irradiation, and ozone disinfection cannot remove ARGs completely. In this study, the potential of electrochemical oxidation and electro-Fenton processes as alternative treatment technologies for inactivation of ARB and ARGs in both intracellular and extracellular forms was evaluated. Results showed that the electrochemical oxidation process was effective for the inactivation of selected ARB but not for the removal of intracellular ARGs or extracellular ARGs. The electro-Fenton process was more effective for the removal of both intracellular and extracellular ARGs. The removal efficiency after 120 min of electro-Fenton treatment under 21.42 mA/cm(2) was 3.8 logs for intracellular tetA, 4.1 logs for intracellular ampC, 5.2 logs for extracellular tetA, and 4.8 logs for extracellular ampC, respectively in the presence of 1.0 mmol/L Fe(2+). It is suggested that electrochemical oxidation is an effective disinfection method for ARB and the electro-Fenton process is a promising technology for the removal of both intracellular and extracellular ARGs in wastewater.202032701499
7820170.9997Metagenomic analysis of MWWTP effluent treated via solar photo-Fenton at neutral pH: Effects upon microbial community, priority pathogens, and antibiotic resistance genes. The effectiveness of advanced technologies on eliminating antibiotic resistant bacteria (ARB) and resistance genes (ARGs) from wastewaters have been recently investigated. Solar photo-Fenton has been proven effective in combating ARB and ARGs from Municipal Wastewater Treatment Plant effluent (MWWTPE). However, most of these studies have relied solely on cultivable methods to assess ARB removal. This is the first study to investigate the effect of solar photo-Fenton upon ARB and ARGs in MWWTPE by high throughput metagenomic analysis (16S rDNA sequencing and Whole Genome Sequencing). Treatment efficiency upon priority pathogens and resistome profile were also investigated. Solar photo-Fenton (30 mg L(-1) of Fe(2+) intermittent additions and 50 mg L(-1) of H(2)O(2)) reached 76-86% removal of main phyla present in MWWTPE. An increase in Proteobacteria abundance was observed after solar photo-Fenton and controls in which H(2)O(2) was present as an oxidant (Fenton, H(2)O(2) only, solar/H(2)O(2)). Hence, tolerance mechanisms presented by this group should be further assessed. Solar photo-Fenton achieved complete removal of high priority Staphylococcus and Enterococcus, as well as Klebsiella pneumoniae and Pseudomonas aeruginosa. Substantial reduction of intrinsically multi-drug resistant bacteria was detected. Solar photo-Fenton removed nearly 60% of ARGs associated with sulfonamides, macrolides, and tetracyclines, and complete removal of ARGs related to β-lactams and fluoroquinolones. These results indicate the potential of using solar-enhanced photo-Fenton to limit the spread of antimicrobial resistance, especially in developing tropical countries.202134467925
7607180.9997Inactivation of Antibiotic Resistant Bacteria and Resistance Genes by Ozone: From Laboratory Experiments to Full-Scale Wastewater Treatment. Ozone, a strong oxidant and disinfectant, seems ideal to cope with future challenges of water treatment, such as micropollutants, multiresistant bacteria (MRB) and even intracellular antibiotic resistance genes (ARG), but information on the latter is scarce. In ozonation experiments we simultaneously determined kinetics and dose-dependent inactivation of Escherichia coli and its plasmid-encoded sulfonamide resistance gene sul1 in different water matrixes. Effects in E. coli were compared to an autochthonous wastewater community. Furthermore, resistance elimination by ozonation and post-treatment were studied in full-scale at a wastewater treatment plant (WWTP). Bacterial inactivation (cultivability, membrane damage) and degradation of sul1 were investigated using plate counts, flow cytometry and quantitative real-time PCR. In experiments with E. coli and the more ozone tolerant wastewater community disruption of intracellular genes was observed at specific ozone doses feasible for full-scale application, but flocs seemed to interfere with this effect. At the WWTP, regrowth during postozonation treatment partly compensated inactivation of MRB, and intracellular sul1 seemed unaffected by ozonation. Our findings indicate that ozone doses relevant for micropollutant abatement from wastewater do not eliminate intracellular ARG.201627775322
7841190.9997Simultaneous removal of antibiotics and antibiotic resistance genes in wastewater by a novel nonthermal plasma/peracetic acid combination system: Synergistic performance and mechanism. In this study, a novel and green method combining plasma with peracetic acid (plasma/PAA) was developed to simultaneously remove antibiotics and antibiotic resistance genes (ARGs) in wastewater, which achieves significant synergistic effects in the removal efficiencies and energy yield. At a plasma current of 2.6 A and PAA dosage of 10 mg/L, the removal efficiencies of most detected antibiotics in real wastewater exceeded 90 % in 2 min, with the ARG removal efficiencies ranging from 6.3 % to 75.2 %. The synergistic effects of plasma and PAA could be associated with the motivated production of reactive species (including •OH, •CH(3), (1)O(2), ONOO(-), •O(2)(-) and NO•), which decomposed antibiotics, killed host bacteria, and inhibited ARG conjugative transfer. In addition, plasma/PAA also changed the contributions and abundances of ARG host bacteria and downregulated the corresponding genes of two-component regulatory systems, thus reducing ARG propagation. Moreover, the weak correlations between the removal of antibiotics and ARGs highlights the commendable performance of plasma/PAA in the simultaneous removal of antibiotics and ARGs. Therefore, this study affords an innovative and effective avenue to remove antibiotics and ARGs, which relies on the synergistic mechanisms of plasma and PAA and the simultaneous removal mechanisms of antibiotics and ARGs in wastewater.202337027926