Inactivation of antibiotic resistant Escherichia coli and degradation of its resistance genes by glow discharge plasma in an aqueous solution. - Related Documents




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778801.0000Inactivation of antibiotic resistant Escherichia coli and degradation of its resistance genes by glow discharge plasma in an aqueous solution. Emerging contaminants such as antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are becoming a global environmental problem. In this study, the glow discharge plasma (GDP) was applied for degrading antibiotic resistant Escherichia coli (E. coli) with resistance genes (tetA, tetR, aphA) and transposase gene (tnpA) in 0.9% sterile saline. The results showed that GDP was able to inactivate the antibiotic resistant E. coli and remove the ARGs and reduce the risk of gene transfer. The levels of E. coli determined by 16S rRNA decreased by approximately 4.7 logs with 15 min of discharge treatment. Propidium monoazide - quantitative polymerase chain reaction (PMA-qPCR) tests demonstrated that the cellular structure of 4.8 more logs E. coli was destroyed in 15 min. The reduction of tetA, tetR, aphA, tnpA genes was increased to 5.8, 5.4, 5.3 and 5.5 logs with 30 min discharge treatment, respectively. The removal of ARGs from high salinity wastewater was also investigated. The total abundance of ARGs was reduced by 3.9 logs in 30 min. Scavenging tests indicated that hydroxyl radicals (·OH) was the most probable agents for bacteria inactivation and ARGs degradation. In addition, the active chlorine (Cl· and Cl(2)) which formed during the discharge may also contribute to the inactivation and degradation.202032229364
778910.9998Simultaneous removal of antibiotic-resistant Escherichia coli and its resistance genes by dielectric barrier discharge plasma. As emerging contaminants, antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been widely detected in various aqueous environments. For antibiotic resistance to be inhibited in the environment, it is essential to control ARB and ARGs. In this study, dielectric barrier discharge (DBD) plasma was used to inactivate antibiotic resistant Escherichia coli (AR E. coli) and remove ARGs simultaneously. Within 15 s of plasma treatment, 10(8) CFU/mL of AR E. coli were inactivated by 97.9%. The rupture of the bacterial cell membrane and the increase of intracellular ROS are the main reasons for the rapid inactivation of bacteria. Intracellular ARGs (i-qnrB, i-blaCTX-M, i-sul2) and integron gene (i-int1) decreased by 2.01, 1.84, 2.40, and 2.73 log after 15 min of plasma treatment, respectively. In the first 5 min of discharge, extracellular ARGs (e-qnrB, e-blaCTX-M, e-sul2) and integron gene (e-int1) decreased by 1.99, 2.22, 2.66, and 2.80 log, respectively. The results of the ESR and quenching experiments demonstrated that ·OH and (1)O(2) played important roles in the removal of ARGs. This study shows that DBD plasma is an effective technique to control ARB and ARGs in waters.202337217128
780720.9998Copper 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
779430.9998Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control. This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L). The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L). By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L). However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.201525738838
782440.9998H(2)O(2) and/or TiO(2) photocatalysis under UV irradiation for the removal of antibiotic resistant bacteria and their antibiotic resistance genes. Inactivating antibiotic resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) are very important to prevent their spread into the environment. Previous efforts have been taken to eliminate ARB and ARGs from aqueous solution and sludges, however, few satisfying results have been obtained. This study investigated whether photocatalysis by TiO(2) was able to reduce the two ARGs, mecA and ampC, within the host ARB, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. The addition of H(2)O(2) and matrix effect on the removal of ARB and ARGs were also studied. TiO(2) thin films showed great effect on both ARB inactivation and ARGs removal. Approximately 4.5-5.0 and 5.5-5.8 log ARB reductions were achieved by TiO(2) under 6 and 12mJ/cm(2) UV(254) fluence dose, respectively. For ARGs, 5.8 log mecA reduction and 4.7 log ampC reduction were achieved under 120mJ/cm(2) UV(254) fluence dose in the presence of TiO(2). Increasing dosage of H(2)O(2) enhanced the removal efficiencies of ARB and ARGs. The results also demonstrated that photocatalysis by TiO(2) was capable of removing both intracellular and extracellular forms of ARGs. This study provided a potential alternative method for the removal of ARB and ARGs from aqueous solution.201727776873
779550.9998Factors influencing the removal of antibiotic-resistant bacteria and antibiotic resistance genes by the electrokinetic treatment. The performance of the electrokinetic remediation process on the removal of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) was evaluated with different influencing factors. With chlortetracycline (CTC), oxytetracycline (OTC), and tetracycline (TC) as template chemicals, the removal of both ARB and ARGs was enhanced with the increase of voltage gradient (0.4-1.2 V cm(-1)) and prolonged reaction time (3-14 d). The greatest removal (26.01-31.48% for ARB, 37.93-83.10% for ARGs) was obtained applying a voltage of 1.2 V cm(-1), leading to the highest electrical consumption. The effect of polarity reversal intervals on the inactivation ratio of ARB followed the order of 0 h (66.06-80.00%) > 12 h (17.07-24.75%) > 24 h (10.44-13.93%). Lower pH, higher current density, and more evenly-distributed voltage drop was observed with a polarity reversal interval of 12 h compared with that of 24 h, leading to more efficient electrochemical reactions in soil. Compared with sul genes, tet genes were more vulnerable to be attacked in an electric field. It was mainly attributed to the lower abundance of tet genes (except tetM) and the varied effects of electrokinetic remediation process on different ARGs. Moreover, a relatively less removal ratio of tetC and tetG was obtained mainly due to the mechanism of the efflux pump upregulation. Both tet and sul genes were positively correlated with TC-resistant bacteria. The efflux pump genes like tetG and the cellular protection genes like tetM showed different correlations with ARB. This study enhances the current understanding on the removal strategies of ARB and ARGs, and it provides important parameters for their destruction by the electrokinetic treatment.201829807293
784760.9998Inactivation 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
784670.9998Removal 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
780880.9997Visible light-driven C/O-g-C(3)N(4) activating peroxydisulfate to effectively inactivate antibiotic resistant bacteria and inhibit the transformation of antibiotic resistance genes: Insights on the mechanism. Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) dissemination within water pose a serious threat to public health. Herein, C and O dual-doped g-C(3)N(4) (C/O-g-C(3)N(4)) photocatalyst, fabricated via calcination treatment, was utilized to activate peroxydisulfate (PDS) to investigate the disinfection effect on tetracycline-resistant Escherichia coli and the transformation frequency of ARGs. As a result, approximately 7.08 log E. coli were inactivated, and 72.36 % and 53.96 % of antibiotics resistance gene (tetB) and 16 S rRNA were degraded respectively within 80 min. Futhermore, the transformation frequency was reduced to 0.8. Characterization and theoretical results indicated that C and O doping in g-C(3)N(4) might lead to the electronic structure modulation and band gap energy reduction, resulting in the production of more free radicals. The mechanism analysis revealed that C/O-g-C(3)N(4) exhibited a lower adsorption energy and reaction energy barrier for PDS compared to g-C(3)N(4). This was beneficial for the homolysis of O-O bonds, forming SO(4)(•-) radicals. The attack of the generated active species led to oxidative stress in cells, resulting in damage to the electron transport chain and inhibition of ATP production. Our findings disclose a valuable insight for inactivating ARB, and provide a prospective strategy for ARGs dissemination in water contamination.202437976858
776690.9997Native Microalgae-Bacteria Consortia: A Sustainable Approach for Effective Urban Wastewater Bioremediation and Disinfection. Urban wastewater is a significant by-product of human activities. Conventional urban wastewater treatment plants have limitations in their treatment, mainly concerning the low removal efficiency of conventional and emerging contaminants. Discharged wastewater also contains harmful microorganisms, posing risks to public health, especially by spreading antibiotic-resistant bacteria and genes. Therefore, this study assesses the potential of a native microalgae-bacteria system (MBS) for urban wastewater bioremediation and disinfection, targeting NH(4)(+)-N and PO(4)(3-)-P removal, coliform reduction, and antibiotic resistance gene mitigation. The MBS showed promising results, including a high specific growth rate (0.651 ± 0.155 d(-1)) and a significant average removal rate of NH(4)(+)-N and PO(4)(3-)-P (9.05 ± 1.24 mg L(-1) d(-1) and 0.79 ± 0.06 mg L(-1) d(-1), respectively). Microalgae-induced pH increase rapidly reduces coliforms (r > 0.9), including Escherichia coli, within 3 to 6 days. Notably, the prevalence of intI1 and the antibiotic resistance genes sul1 and bla(TEM) are significantly diminished, presenting the MBS as a sustainable approach for tertiary wastewater treatment to combat eutrophication and reduce waterborne disease risks and antibiotic resistance spread.202439065189
7793100.9997Treatment of pharmaceutical wastewater by ionizing radiation: Removal of antibiotics, antimicrobial resistance genes and antimicrobial activity. In present study, the treatment of real pharmaceutical wastewater from an erythromycin (ERY) production factory by gamma irradiation was investigated. Results showed that a variety of antimicrobial resistance genes (ARGs), involving MLSB, tet, bla, multidrug, sul, MGEs and van genes and plentiful 9 bacterial phyla were identified in the raw wastewater. In addition to ERY, sulfamethoxazole (SMX) and tetracycline (TC) were also identified with the concentration of 3 order of magnitude lower than ERY. Results showed that the abatement of ARGs and antibiotics was much higher than that of antimicrobial activity and COD. With the absorbed dose of 50 kGy, the removal percentage of ARGs, ERY, antimicrobial activity and COD was 96.5-99.8%, 90.0%, 47.8% and 10.3%, respectively. The culturable bacteria were abated fast and completely at 5.0 kGy during gamma irradiation. The genus Pseudomonas was predominant in raw wastewater (56.7%) and its relative abundance decreased after gamma irradiation, to 1.3% at 50 kGy. With addition of peroxymonosulfate (PMS, 50 mM), the antimicrobial activity disappeared completely and ERY removal reached as high as 99.2% at the lower absorbed dose of 25 kGy. Ionizing radiation-coupled technique is a potential option to treat pharmaceutical wastewater for reduction of antibiotics, ARGs and antimicrobial activity.202134088196
8035110.9997Effects of hydrothermal treatment on the reduction of antibiotic-resistant Escherichia coli and antibiotic resistance genes and the fertilizer potential of liquid product from cattle manure. In this study, the reduction in the abundance of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) and the fertilizer potential of liquid products from hydrothermally treated cattle manure were investigated. Hydrothermal treatment (HTT) was conducted under different reaction temperatures (125, 150, 175 and 200 °C) and retention times (60, 90 and 120 min). The total organic carbon (TOC) and total nitrogen (TN) of the liquid product increased with increasing reaction temperature. The germination index (GI), a measure of the percentage of germination, exceeded 90 % at 125, 150, and 175 °C in diluted samples, while it decreased to 18 % at 200 °C. Although a longer retention time contributed to an increase in TOC of liquid products, it did not increase the GI values. The liquid product should be diluted or adjusted before use as fertilizer to prevent phytotoxicity. In our analysis of ARB and ARGs, E. coli and antibiotic-resistant E. coli were completely reduced after HTT, except for the operating conditions of 125 °C and 60 min. Although both a higher reaction temperature and longer retention time tended to be better for the reduction of ARGs and intI1, it was found that the longer retention time is much more effective than the higher reaction temperature. The reduction of target ARGs and intI1 was 2.9-log under175 °C and 120 min. Comprehensively considering the fertilizer potential of liquid product and the reduction of ARB and ARGs, 175 °C of reaction temperature and 120 min of retention time of operating conditions for HTT were recommended.202438744164
7763120.9997Antibiotic resistance genes fate and removal by a technological treatment solution for water reuse in agriculture. In order to mitigate the potential effects on the human health which are associated to the use of treated wastewater in agriculture, antibiotic resistance genes (ARGs) are required to be carefully monitored in wastewater reuse processes and their spread should be prevented by the development of efficient treatment technologies. Objective of this study was the assessment of ARGs reduction efficiencies of a novel technological treatment solution for agricultural reuse of municipal wastewaters. The proposed solution comprises an advanced biological treatment (Sequencing Batch Biofilter Granular Reactor, SBBGR), analysed both al laboratory and pilot scale, followed by sand filtration and two different disinfection final stages: ultraviolet light (UV) radiation and peracetic acid (PAA) treatments. By Polymerase Chain Reaction (PCR), the presence of 9 ARGs (ampC, mecA, ermB, sul1, sul2, tetA, tetO, tetW, vanA) were analysed and by quantitative PCR (qPCR) their removal was determined. The obtained results were compared to the reduction of total bacteria (16S rDNA gene) and of a faecal contamination indicator (Escherichia coli uidA gene). Only four of the analysed genes (ermB, sul1, sul2, tetA) were detected in raw wastewater and their abundance was estimated to be 3.4±0.7 x10(4) - 9.6±0.5 x10(9) and 1.0±0.3 x10(3) to 3.0±0.1 x10(7) gene copies/mL in raw and treated wastewaters, respectively. The results show that SBBGR technology is promising for the reduction of ARGs, achieving stable removal performance ranging from 1.0±0.4 to 2.8±0.7 log units, which is comparable to or higher than that reported for conventional activated sludge treatments. No reduction of the ARGs amount normalized to the total bacteria content (16S rDNA), was instead obtained, indicating that these genes are removed together with total bacteria and not specifically eliminated. Enhanced ARGs removal was obtained by sand filtration, while no reduction was achieved by both UV and PAA disinfection treatments tested in our study.201627450254
7787130.9997Inactivation of a pathogenic NDM-1-positive Escherichia coli strain and the resistance gene bla(NDM-1) by TiO(2)/UVA photocatalysis. Proliferation of bla(NDM-1) in water and wastewater is particularly concerning because of multidrug-resistance and horizontal transfer of the gene. In the present study, a pathogenic NDM-1-positive Escherichia coli strain (named E. coli NDM-1) and the bla(NDM-1) gene were treated with titanium dioxide (TiO(2))/ultraviolet A (UVA) photocatalysis. Effects of catalyst dose, UVA intensity, and phosphate on bacteria and intracellular and extracellular bla(NDM-1) genes were determined. With increases in TiO(2) dose and UVA intensity, the inactivation rate of E. coli NDM-1 increased greatly in saline solution. However, phosphate in water hindered adsorption of bacteria to TiO(2) and partly changed the TiO(2) photocatalytic pathway, resulting in low degradation efficiency. Although inactivation of E. coli NDM-1 was highly efficient, TiO(2)/UVA photocatalysis had little effect on removal of the bla(NDM-1) gene. During the 2-h photocatalytic experiments, E. coli cells decreased by 4.7-log, while the bla(NDM-1) gene decreased by 0.7- ~ 1.5-log. Moreover, the degradation rate of extracellular bla(NDM-1) was ~2.7 times higher than that of intracellular genes. Abundance and transformation frequency of residual bla(NDM-1) genes remained high, even when bacteria were completely inactivated, indicating potential health risks. Increases in treatment time and UVA irradiation intensity are needed to remove the bla(NDM-1) gene to sufficiently low levels.202235842147
8005140.9997Deciphering the fate of antibiotic resistance genes in norfloxacin wastewater treated by a bio-electro-Fenton system. The misuse of antibiotics has increased the prevalence of antibiotic resistance genes (ARGs), considered a class of critical environmental contaminants due to their ubiquitous and persistent nature. Previous studies reported the potentiality of bio-electro-Fenton processes for antibiotic removal and ARGs control. However, the production and fate of ARGs in bio-electro-Fenton processes triggered by microbial fuel cells are rare. In this study, the norfloxacin (NFLX) average residual concentrations within two days were 2.02, 6.07 and 14.84 mg/L, and the average removal efficiency of NFLX was 79.8 %, 69.6 % and 62.9 % at the initial antibiotic concentrations of 10, 20 and 40 mg/L, respectively. The most prevalent resistance gene type in all processes was the fluoroquinolone antibiotic gene. Furthermore, Proteobacteria was the dominant ARG-carrying bacteria. Overall, this study can provide theoretical support for the efficient treatment of high antibiotics-contained wastewater by bio-electro-Fenton systems to better control ARGs from the perspective of ecological security.202236252757
7765150.9997Antibiotic resistance bacteria and antibiotic resistance genes survived from the extremely acidity posing a risk on intestinal bacteria in an in vitro digestion model by horizontal gene transfer. Antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants posing risk to human health. To investigate the pathogenic ARBs and the horizontal gene transfer (HGT) via both extracellular ARGs (eARGs) and intracellular ARGs (iARGs), an in vitro digestion simulation system was established to monitoring the ARB and ARGs passing through the artificial digestive tract. The results showed that ARB was mostly affected by the acidity of the gastric fluid with about 99% ARB (total population of 2.45 × 10(9)-2.54 × 10(9)) killed at pH 2.0 and severe damage of bacterial cell membrane. However, more than 80% ARB (total population of 2.71 × 10(9)-3.90 × 10(9)) survived the challenge when the pH of the gastric fluid was 3.0 and above. Most ARB died from the high acidity, but its ARGs, intI1 and 16 S rRNA could be detected. The eARGs (accounting for 0.03-24.56% of total genes) were less than iARGs obviously. The eARGs showed greater HGT potential than that of iARGs, suggesting that transformation occurred more easily than conjugation. The transferring potential followed: tet (100%) > sul (75%) > bla (58%), related to the high correlation of intI1 with tetA and sul2 (p < 0.01). Moreover, gastric juice of pH 1.0 could decrease the transfer frequency of ARGs by 2-3 order of magnitude compared to the control, but still posing potential risks to human health. Under the treatment of digestive fluid, ARGs showed high gene horizontal transfer potential, suggesting that food-borne ARBs pose a great risk of horizontal transfer of ARGs to intestinal bacteria.202236332408
7791160.9997Investigation of reduction in risk from antibiotic resistance genes in laboratory wastewater by using O(3) , ultrasound, and autoclaving. Biological laboratory wastewater containing both antibiotic-resistant bacteria (ARB) and antibiotics is a potential source of antibiotic resistance genes (ARGs). Thus, we determined the efficacy of autoclaving, a common disinfection method, in eliminating 5 ARGs (sul1, sul2, tetW, tetM, amp) and the integrase-encoding gene intI1 from laboratory wastewater. Autoclaving (15 min, 121°C) inactivated all bacteria including ARB, whereas ARGs persisted in the wastewater with limited reduction even after 60 min of treatment. Ozonation (O(3) ), ultrasound (US), O(3) /US, and autoclaving followed by O(3) were investigated for their ability to reduce ARGs in laboratory wastewater. With O(3) and O(3) /US, the reduction rate ranged from 5.44 to 7.13 log for all ARGs investigated. Wastewater treatment with US alone did not reduce ARGs under the present experimental conditions (150 W, 53 kHz). Among the four treatments, autoclaving followed by O(3) treatment showed the highest reduction rates in the shortest time; however, further optimization and investigation are needed for the advanced treatment of bio-laboratory wastewater. Overall, this study provides novel insights into ARG sources and demonstrates that advanced oxidation methods can be useful to optimize laboratory wastewater treatment for ARG inactivation. PRACTITIONER POINTS: Bio-laboratory wastewater is potential reservoir of ARGs. Conventional autoclaving was not able to reduce ARGs to a low level. Autoclaving-O(3) completely eliminate all the bacteria. Autoclaving-O(3) reduced ARGs efficiently (6.12-7.86 logs removal in 60 min).202132891064
7866170.9997Inactivation of sulfonamide antibiotic resistant bacteria and control of intracellular antibiotic resistance transmission risk by sulfide-modified nanoscale zero-valent iron. The inactivation of a gram-negative sulfonamide antibiotic resistant bacteria (ARB) HLS.6 and removal of intracellular antibiotic resistance gene (ARG, sul1) and class I integrase gene (intI1) by nanoscale zero-valent iron (nZVI) and sulfide-modified nZVI (S-nZVI) with different S/Fe molar ratios were investigated in this study. The S-nZVI with high sulfur content (S/Fe = 0.05, 0.1, 0.2) was superior to nZVI and the treatment effect was best when S/Fe was 0.1. The ARB (2 × 10(7) CFU/mL) could be completely inactivated by 1.12 g/L of S-nZVI (S/Fe = 0.1) within 15 min, and the removal rates of intracellular sul1 and intI1 reached up to 4.39 log and 4.67 log at 60 min, respectively. Quenching experiments and flow cytometry proved that reactive oxygen species and adsorption were involved in the ARB inactivation and target genes removal. Bacterial death and live staining experiments and transmission electron microscopy showed that the ARB cell structure and intracellular DNA were severely damaged after S-nZVI treatment. This study provided a potential alternative method for controlling the antibiotic resistance in aquatic environment.202032585519
7792180.9997Comparative removal of two antibiotic resistant bacteria and genes by the simultaneous use of chlorine and UV irradiation (UV/chlorine): Influence of free radicals on gene degradation. The research aimed to remove antibiotic resistance by the simultaneous use of UV irradiation and chlorine (UV/chlorine). The inactivations of tetracycline resistant bacteria (TRB) during chlorination, UV irradiation, and UV/chlorine was investigated and compared with those of amoxicillin resistant bacteria (AmRB). Similar examination was also conducted for comparing the removals of their resistant genes (i.e., tetM and blaTem). The removals of antibiotic resistance highly depended on chlorine doses and UV intensities. The sufficient chlorine dose (20 mg.L(-1)) in the chlorination and the UV/chlorine completely inactivated TRB and AmRB (>7.3 log), while the UV irradiation could not achieve the complete disinfection. Microorganisms resistant to different antibiotics exhibit different susceptibility to the disinfection processes. The removals of antibiotic resistant genes (i.e., tetM and blaTem) were more difficult than those of TRB and AmRB. The UV/chlorine was the greatest process for tetM and blaTem removals, followed by chlorination and UV irradiation, respectively. Chlorination decreased the tetM and blaTem by 0.40-1.45 log and 1.04-2.45 log, respectively. The blaTem gene was highly reactive to chlorine, compared with tetM. The UV irradiation caused the tetM and blaTem reductions by 0.32-0.91 log and 0.59-0.96 log, respectively. The UV/chlorine improved the tetM and blaTem removals by 0.98-3.20 log and 1.28-3.36 log, respectively. The •OH contributed to the fraction of tetM and blaTem removals by 48% and 19%, respectively. The effect of reactive chlorine species on the tetM and blaTem removals was minor. The pseudo 1st-order kinetic constants (k') for tetM and blaTem removals by the UV/chlorine were highest. The •OH enhanced the k' values by 120% and 20% for the tetM and blaTem removals, respectively. The study showed the potential use of UV/chlorine for controlling antibiotic resistance.202133059146
7204190.9997Solar-light driven photodegradation of antimicrobials, their transformation by-products and antibiotic resistance determinants in treated wastewater. This study aimed to assess the possibility of using solar light-driven photolysis and TiO(2)-based photocatalysis to remove (1) antibiotic residues, (2) their transformation products (TPs), (3) antibiotic resistance determinants, and (4) genes identifying the indicator bacteria in a treated wastewater (secondary effluent). 16 antimicrobials belonging to the different classes and 45 their transformation by-products were selected for the study. The most susceptible to photochemical decomposition was tetracycline, which was completely removed in the photocatalysis process and in more than 80% in the solar light-driven photolysis. 83.8% removal (on average) was observed using photolysis and 89.9% using photocatalysis in the case of the tested genes, among which the genes sul1, uidA, and intI1 showed the highest degree of removal by both methods. The study revealed that applied methods promisingly remove the tested antibiotics, their TPs and genes even in such a complex matrix including treated wastewater and photocatalysis process had a higher removal efficiency of antibiotics, TPs and genes tested. Moreover, the high percentage removal of the intI1 gene (>93%) indicates the possibilities of use of the solar light-driven photolysis and TiO(2)-based photocatalysis in minimizing the antibiotic resistance genes transfer by mobile genetic elements.202235469868