Simultaneous elimination of antibiotics and antibiotics resistance genes in nitritation of source-separated urine. - Related Documents




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804701.0000Simultaneous elimination of antibiotics and antibiotics resistance genes in nitritation of source-separated urine. Antibiotics in human urine could accelerate dissemination of antibiotics resistance genes (ARGs), posing potential threat to sewage. The nitritation of source-separated urine was a critical step to realize the urine resourcelization and nitrogen stabilization. However, the synergic control on antibiotics and ARGs during urine nitritation was unrevealed. This study investigated the removal profiles of five typical antibiotics and the shifts of microbial community and ARGs during stable nitritation. The result showed that sulfamethoxazole and roxithromycin were effectively eliminated with high removal efficiency of (95 ± 5) % and (90 ± 10) %, followed by enrofloxacin with removal efficiency of (60 ± 5) %, whereas trimethoprim and chloramphenicol showed low removal efficiency of less than 40 %. Ammonia oxidation bacteria and heterotrophic bacteria equally contributed to elimination of sulfamethoxazole with a high biodegradation rate of 0.1534 L/gVSS·h, while sorption and biodegradation jointly promoted other antibiotics removal. The total relative abundance of top 25 bacteria genera was decreased by 10 %. The total relative abundance of top 30 ARGs was decreased by more than 20 %, which was corresponding to the variation of bacterial community. The findings in this research would get a deeper insight into the eliminating antibiotics and controlling ARGs dissemination during nitritation of source-separated urine.202235897182
800410.9997Elimination of antibiotic-resistant bacteria and resistance genes by earthworms during vermifiltration treatment of excess sludge. Vermifiltration (VF) and a conventional biofilter (BF, no earthworm) were investigated by metagenomics to evaluate the removal rates of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and class 1 integron-integrase (intI1), as well as the impact mechanism in combination with the microbial community. According to the findings of qPCR and metagenomics, the VF facilitated greater removal rates of ARGs (78.83% ± 17.37%) and ARB (48.23% ± 2.69%) than the BF (56.33% ± 14.93%, 20.21% ± 6.27%). Compared to the control, the higher biological activity of the VF induced an increase of over 60% in the inhibitory effect of earthworm coelomic fluid on ARB. The removal rates of ARGs by earthworm guts also reached over 22%. In addition, earthworms enhanced the decomposition of refractory organics, toxic, and harmful organics, which led to a lower selective pressure on ARGs and ARB. It provides a strategy for reducing resistant pollution in sewage treatment plants and recognizing the harmless stability of sludge.202438170354
800320.9997Dynamics of antibiotic resistance agents during sludge alkalinization treatment. This study aimed to assess the removal of antimicrobial resistance agents (antibiotics, antibiotic-resistant bacteria - ARB, and antimicrobial resistance genes - ARGs) from aerobic and anaerobic sludges treated with quicklime (chemical alkalinization). Different mixing ratios (25%, 35%, and 45%) and contact times (2 h and 72 h) were evaluated. The findings revealed that anaerobic sludge responded more effectively to alkaline treatment, achieving better removal rates of antibiotics, ARB, and ARGs compared to aerobic sludge. The 45% lime treatment yielded the highest antibiotic removal rates, with average reductions of 19% in aerobic sludge and 28% in anaerobic sludge. The 35% lime treatment was the most effective in reducing ARGs across both types of sludge (average removal of 2 logs). The 25% lime treatment proved most efficient for removing ARB, with average reductions of 4 logs (aerobic) and 5 logs (anaerobic). The contact time between the sludge and quicklime also influenced the removal of resistance agents. An increase in the proportion of antibiotics and the absolute concentration of ARB and ARGs was observed after 72 h compared to the samples analyzed after 2 h of contact. This increase was more pronounced in aerobic sludge samples treated with 35% and 45% lime. Despite the overall reduction, none of the monitored resistant genes or bacteria were completely eradicated in both sludge samples, raising concerns about their potential dissemination into the environment.202439414064
808430.9997Metagenomic insights into effects of carbon/nitrogen ratio on microbial community and antibiotic resistance in moving bed biofilm reactor. This study investigated the effects of carbon/nitrogen (C/N) ratio on microbial community in moving bed biofilm reactor (MBBR) using metagenomic analysis, and the dynamic changes of relevant antibiotic resistance genes (ARGs) were also analyzed. The results showed that under low C/N ratio, MBBR exhibited average removal rates of 98.41 % for ammonia nitrogen and 75.79 % for total nitrogen. Metagenomic analysis showed low C/N ratio altered the structure of biofilm and water microbiota, resulting in the detachment of bacteria such as Actinobacteria from biofilm into water. Furthermore, sulfamethazine (SMZ)-resistant bacteria and related ARGs were released into water under low C/N ratio, which lead to the increase of SMZ resistance rate to 90%. Moreover, most dominant genera are potential hosts for both nitrogen cycle related genes and ARGs. Specifically, Nitrosomonas that carried gene sul2 might be released from biofilm into water. These findings implied the risks of antibiotic resistance dissemination in MBBR under low C/N ratio.202438901747
800540.9997Deciphering 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
779550.9996Factors 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
800260.9996Selective effect and elimination of antibiotics in membrane bioreactor of urban wastewater treatment plant. Analyzing the temporal dynamics of antibiotics, antibiotic resistance genes (ARGs) and the functional community could contribute to the regulation and optimization of wastewater treatment plant (WWTP) operation to achieve better antibiotics and ARGs removal performances during different seasons. However, there is little research in this area. Therefore, in this study, samples were collected from the influent, activated sludge (AS), and permeate of the membrane bioreactor (MBR) in a WWTP located in Beijing, China, biweekly over 13 months, and then analyzed systematically. The removal efficiency for all detected antibiotics through biodegradation and adsorption was 59.25 ± 2.79%, with the highest rate of 64.79 ± 4.68% observed in summer, indicating that the higher temperature in summer may promote biodegradation in MBR. In contrast, the elimination of antibiotics through microfiltration was negligible and unfavorable, with negative overall removal rates. However, a positive rejection rate of 9.48 ± 8.92% was only observed in winter, indicating that a colder temperature might lead to better, but still limited, antibiotics rejection. Sulfonamides (SAs) were more likely to impose a selective pressure on their corresponding ARGs. However, due to the degradability of tetracyclines (TCs) and potential selection of ARGs in wastewater before entering WWTP, there were still TC resistances with non-detectable TCs. Significantly negative relationships were observed between the relative abundance of nitrifying bacteria (Nitrosomonas and Nitrospira) and the concentrations of certain antibiotic classes, indicating that nitrifying bacteria could be involved in the co-metabolic biodegradation of certain antibiotics through enzyme catalyzation during nitrification.201930235615
718970.9996Comparative effects of different antibiotics on antibiotic resistance during swine manure composting. This study explored commonly-used antibiotics (lincomycin, chlorotetracycline, sulfamethoxazole, and ciprofloxacin) and their collective effects on antibiotic resistance during composting. In the first 7 days, ciprofloxacin showed the greatest influence on the physicochemical factors among the studied antibiotics; the removal of antibiotic resistance genes (ARGs) in the multiple-antibiotic treatment was significantly less than single-antibiotic treatments; especially, the largest removal of ribosomal protection genes (tetW and tetO) occurred in single ciprofloxacin treatment. In the end of composting, similar removal ratio (29.71-99.79%) of ARGs was achieved in different treatments (p greater than 0.05); Chloroflexi became the main phylum and it was closely associated with ARGs removal based on the network analysis. Potential host bacteria of ARGs varied with different antibiotics; in particular, the presence of multiple antibiotics increased potential host bacteria of ermA, sul1 and tetO. Above all, collective effects of different antibiotics led to the enrichment of antibiotic resistance in the composting.202032712514
801380.9996New insight into fates of sulfonamide and tetracycline resistance genes and resistant bacteria during anaerobic digestion of manure at thermophilic and mesophilic temperatures. This study investigated the variations in antibiotic (sulfonamide and tetracycline) resistance genes (ARGs) and resistant bacteria (ARB) during manure anaerobic digestion (AD) at 35 ℃ and 55 ℃, and discussed the mechanisms of variations in ARGs. The AD lasted for 60 days, five ARGs and intI1 each decreased in abundance after AD at the thermophilic temperature, while only half decreased at the mesophilic temperature. On days 10, 30, and 60, sulfonamide and tetracycline ARB were screened on selective media. During thermophilic AD, ARB numbers reduced by 4-log CFUs per gram dry manure, but only by approximately 1-log CFU at the mesophilic temperature. However, ARB composition analysis showed that at either temperature, no significant reduction in identified ARB species was observed. Furthermore, 72 ARB clones were randomly selected to detect the ARGs they harbored, and the results showed that each ARG was harbored by various hosts, and no definitive link existed between ARGs and bacterial species. In addition, by comparison with the identified host by culture method, the host prediction results based on the correlation analysis between ARGs and the bacterial community was proven to be unreliable. Overall, these findings indicated that relationships between ARB and ARGs were intricate.202031685315
804890.9996Ecological risks of sulfonamides and quinolones degradation intermediates: Toxicity, microbial community, and antibiotic resistance genes. The ecological risks posed by incompletely degraded antibiotic intermediates in aquatic environments warrant significant attention. This study investigated the degradation mechanisms of sulfonamides (sulfadiazine, sulfamethoxazole) and quinolones (ciprofloxacin, norfloxacin) during thermally activated persulfate (TAP) treatment. The main degradation mechanisms for sulfonamides involved S-N bond cleavage and -NH(2) oxidation mediated by sulfate and hydroxyl radicals, whereas quinolone degradation occurred primarily through piperazine ring cleavage facilitated by a single linear oxygen. Toxic degradation intermediates were found to be enriched with bacteria in real water samples, including Aeromonas (SDZ-50, 9.61%), Acinetobacter (SMZ-50, 21.91%), unclassified Archaea (CIP-50, 19.32%), and Herbaspirillum (NOR-50, 17.36%). Meanwhile, the abundance of sulfonamide-associated antibiotic resistance genes (ARGs) (sul1 and sul2) and quinolone-associated ARGs (mfpA, emrA, and lfrA) significantly increased, with SMZ-50 and NOR-50 reaching 659.34 and 2009.98 RPKM, respectively. Correlation analysis revealed differences in host diversity and composition driven by the same classes of antibiotics and their intermediates.202539662843
7846100.9996Removal 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
7209110.9996Role of a typical swine liquid manure treatment plant in reducing elements of antibiotic resistance. Biological treatment of swine liquid manure may be a favorable environment for the enrichment of bacteria carrying antibiotic resistance genes (ARGs), raising the alert about this public health problem. The present work sought to investigate the performance of a swine wastewater treatment plant (SWWTP), composed of a covered lagoon biodigester (CLB) followed by three facultative ponds, in the removal of usual pollutants, antibiotics, ARGs (blaTEM, ermB, qnrB, sul1, and tetA), and intI1. The SWWTP promoted a 70% of organic matter removal, mainly by the digester unit. The facultative ponds stood out in the solids' retention carried from the anaerobic stage and contributed to ammonia volatilization. The detected antibiotic in the raw wastewater was norfloxacin (< 0.79 to 60.55 μg L(-1)), and the SWWTP seems to equalize peaks of norfloxacin variation probably due to sludge adsorption. CLB reduced the absolute abundance of ARGs by up to 2.5 log, while the facultative stage does not seem to improve the quality of the final effluent in terms of resistance elements. Considering the relative abundances, the reduction rates of total and ARG-carrying bacteria appear to be similar. Finally, correlation tests also revealed that organic matter and solids control in liquid manure treatment systems could help reduce the spread of ARGs after the waste final disposal.202337477815
8042120.9996Algal-bacterial consortium mediated system offers effective removal of nitrogen nutrients and antibiotic resistance genes. The sulfonamide antibiotic resistance genes (ARGs) especially sul1 was identified as the dominant in eutrophic water. The performance of Chlorella vulgaris-B. licheniformis consortium toward sul1 removal, total nitrogen (TN) removal, and the mechanism of sul1 removal was investigated. The removal efficiency of exogenous ARGs plasmids carrying sul1 reached (97.2 ± 2.3)%. The TN removal rate reached (98.5 ± 1.2)%. The enhancements of carbon metabolism, nitrogen metabolism, aminoacyl-tRNA biosynthesis, and glycoproteins had significant influences on sul1 and TN removals, under the premise of normal growth of algae and bacteria. The quantitative polymerase chain reaction (qPCR) results suggested that the absolute abundances of sul1 were low in algal-bacterial systems (0 gene copies/mL) compared with individual systems ((1 × 10(6) ± 15) gene copies/mL). The duplication of sul1 was inhibited in algal cells and bacterial cells. The algal-bacterial consortium seems to be a promising technology for wastewater treatment with a potential to overcome the eutrophication and ARGs challenges.202236049708
7765130.9996Antibiotic 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
7962140.9996Linking the Effect of Antibiotics on Partial-Nitritation Biofilters: Performance, Microbial Communities and Microbial Activities. The emergence and spread of antibiotics resistance in wastewater treatment systems have been pointed as a major environmental health problem. Nevertheless, research about adaptation and antibiotics resistance gain in wastewater treatment systems subjected to antibiotics has not been successfully developed considering bioreactor performance, microbial community dynamics and microbial activity dynamics at the same time. To observe this in autotrophic nitrogen removal systems, a partial-nitritation biofilter was subjected to a continuous loading of antibiotics mix of azithromycin, norfloxacin, trimethoprim, and sulfamethoxazole. The effect of the antibiotics mix over the performance, bacterial communities and bacterial activity in the system was evaluated. The addition of antibiotics caused a drop of ammonium oxidation efficiency (from 50 to 5%) and of biomass concentration in the bioreactor, which was coupled to the loss of ammonium oxidizing bacteria Nitrosomonas in the bacterial community from 40 to 3%. Biomass in the partial nitritation biofilter experienced a sharp decrease of about 80% due to antibiotics loading, but the biomass adapted and experienced a growth by stabilization under antibiotics feeding. During the experiment several bacterial genera appeared, such as Alcaligenes, Paracoccus, and Acidovorax, clearly dominating the bacterial community with >20% relative abundance. The system reached around 30% ammonium oxidation efficiency after adaptation to antibiotics, but no effluent nitrite was found, suggesting that dominant antibiotics-resistant phylotypes could be involved in nitrification-denitrification metabolisms. The activity of ammonium oxidation measured as amoA and hao gene expression dropped a 98.25% and 99.21%, respectively, comparing the system before and after the addition of antibiotics. On the other hand, denitrifying activity increased as observed by higher expression of nir and nos genes (83.14% and 252.54%, respectively). In addition, heterotrophic nitrification cyt c-551 was active only after the antibiotics addition. Resistance to the antibiotics was presumably given by ermF, carA and msrA for azithromycin, mutations of the gyrA and grlB for norfloxacin, and by sul123 genes for sulfamethoxazole. Joined physicochemical and microbiological characterization of the system were used to investigate the effect of the antibiotics over the bioprocess. Despite the antibiotics resistance, activity of Bacteria decreased while the activity of Archaea and Fungi increased.201829535704
7585150.9996Impacts of engineered nanoparticles and antibiotics on denitrification: Element cycling functional genes and antibiotic resistance genes. The wide presence of antibiotics and minerals warrants their combined effects on the denitrification in natural aquatic environment. Herein, we investigated the effects of two antibiotics, sulfamethazine (SMZ) and chlortetracycline (CTC), on the reduction of NO(3)(-)-N and accumulation of NO(2)(-)-N in the absence and presence of engineered nanoparticles (NPs) (Al(2)O(3), SiO(2), and geothite) using 16 S rRNA sequencing and high-throughput quantitative PCR. The results showed that the addition of antibiotics inhibited the reduction of NO(3)(-)-N by changing the bacterial community structure and reducing the abundance of denitrification genes, while engineered NPs promoted the denitrification by increasing the abundance of denitrification genes. In the binary systems, engineered NPs alleviated the inhibitory effect of antibiotics through enriching the denitrification genes and adsorbing antibiotics. Antibiotics and its combination with engineered NPs changed the composition of functional genes related to C, N, P, S metabolisms (p < 0.01). The addition of antibiotics and/or engineered NPs altered the bacterial community structure, which is dominated by the genera of Enterobacter (40.7-90.5%), Bacillus (4.9-58.5%), and Pseudomonas (0.21-12.7%). The significant relationship between denitrification, carbon metabolism genes, and antibiotic resistance genes revealed that the heterotrophic denitrifying bacteria may host the antibiotic resistance genes and denitrification genes simultaneously. The findings underscore the significance of engineered NPs in the toxicity assessment of pollutants, and provide a more realistic insight into the toxicity of antibiotics in the natural aquatic environment.202235738104
7191160.9996The impact of antimicrobials on the efficiency of methane fermentation of sewage sludge, changes in microbial biodiversity and the spread of antibiotic resistance. The study was designed to simultaneously evaluate the influence of high doses (512-1024 µg/g) the most commonly prescribed antimicrobials on the efficiency of anaerobic digestion of sewage sludge, qualitative and quantitative changes in microbial consortia responsible for the fermentation process, the presence of methanogenic microorganisms, and the fate of antibiotic resistance genes (ARGs). The efficiency of antibiotic degradation during anaerobic treatment was also determined. Metronidazole, amoxicillin and ciprofloxacin exerted the greatest effect on methane fermentation by decreasing its efficiency. Metronidazole, amoxicillin, cefuroxime and sulfamethoxazole were degraded in 100%, whereas ciprofloxacin and nalidixic acid were least susceptible to degradation. The most extensive changes in the structure of digestate microbiota were observed in sewage sludge exposed to metronidazole, where a decrease in the percentage of bacteria of the phylum Bacteroidetes led to an increase in the proportions of bacteria of the phyla Firmicutes and Proteobacteria. The results of the analysis examining changes in the concentration of the functional methanogen gene (mcrA) did not reflect the actual efficiency of methane fermentation. In sewage sludge exposed to antimicrobials, a significant increase was noted in the concentrations of β-lactam, tetracycline and fluoroquinolone ARGs and integrase genes, but selective pressure was not specific to the corresponding ARGs.202133831706
7961170.9996Effect of tetracycline on ammonia and carbon removal by the facultative bacteria in the anaerobic digester of a sewage treatment plant. This study was conducted to see the effect of tetracycline on nitrogen assimilation and carbon removal in an anaerobic digester of a sewage plant. Samples of sewage were collected from an anaerobic digester sludge. Consortium of nitrogen assimilating bacteria were isolated from the sample and its ability to assimilate ammonia at different concentrations of tetracycline was measured along with carbon removal. The results indicate that while high concentrations of tetracycline of more than 100 mg/L delayed the growth of the bacteria, the resistant bacteria grew after a lag period and the removal of nitrogen and carbon was unaffected even at the highest tetracycline concentration of 250 mg/L tested in this study.201830025323
7192180.9996Sulfamethoxazole and COD increase abundance of sulfonamide resistance genes and change bacterial community structures within sequencing batch reactors. The abundant microbial community in biological treatment processes in wastewater treatment plants (WWTPs) may potentially enhance the horizontal gene transfer of antibiotic resistance genes with the presence of antibiotics. A lab-scale sequencing batch reactor was designed to investigate response of sulfonamide resistance genes (sulI, sulII) and bacterial communities to various concentrations of sulfamethoxazole (SMX) and chemical oxygen demand (COD) of wastewater. The SMX concentrations (0.001 mg/L, 0.1 mg/L and 10 mg/L) decreased with treatment time and higher SMX level was more difficult to remove. The presence of SMX also significantly reduced the removal efficiency of ammonia nitrogen, affecting the normal function of WWTPs. All three concentrations of SMX raised both sulI and sulII genes with higher concentrations exhibiting greater increases. The abundance of sul genes was positive correlated with treatment time and followed the second-order reaction kinetic model. Interestingly, these two genes have rather similar activity. SulI and sulII gene abundance also performed similar response to COD. Simpson index and Shannon-Weiner index did not show changes in the microbial community diversity. However, the 16S rRNA gene cloning and sequencing results showed the bacterial community structures varied during different stages. The results demonstrated that influent antibiotics into WWTPs may facilitate selection of ARGs and affect the wastewater conventional treatment as well as the bacteria community structures.201728211331
8012190.9996Sensitive response mechanism of ARGs and MGEs to initial designed temperature during swine manure and food waste co-composting. The rapid aerobic composting process has been used to reduce organic wastes, but the associated risks of antibiotic resistance genes (ARGs) need to evaluate in an efficient way. The primary objective of this work was to explore the underlying mechanism of initial adjustment in composting temperature on the variation of ARGs, mobile genetic elements (MGEs), and microbial composition during co-composting. The co-composting was initially externally heated (T2) for 5 days. The results showed that ARGs abundance in conventional composting (T1) was reduced by 49.36%, while multidrug was enriched by 86.16% after a period of 30 days. While in T2 ARGs were removed by 79.46% particularly the fraction of sulfonamide, multidrug, and vancomycin resistance genes were >90% without rebounding of any ARGs. Whereas, MGEs were reduced by 68.12% and 93.62% in T1 and T2, while the half-lives of ARGs and MGEs were lower in T2 compared to T1 (86.3%,86.7%). T2 also affected the metabolism function by regulating carbohydrate metabolism (9.62-10.39%) and amino acid metabolism (9.92-10.93%). Apart from this, the potential human pathogenic bacteria Pseudomonas was reduced by 90.6% in T2 and only 32.9% in T1 respectively. Network analysis showed that Ureibacillus, Weissella, Corynebacterium, Escherichia-Shigella, Acinetobacter were the main host of multiple genes. Structural equation models exhibited that bacterial communities were mainly responsible for the enrichment of ARGs in T1, whereas, it was directly affected by MGEs in T2. Similarly, ARGs variation was directly related to composting temperature. With this simple strategy, ARGs associated risk can be significantly reduced in composting.202336208781