# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 7859 | 0 | 0.9954 | Abatement of antibiotics and resistance genes during catalytic ozonation enhanced sludge dewatering process: Synchronized in volume and hazardousness reduction. Based on the efficiency of the catalytic ozonation techniques (HDWS+O(3) and MnFe(2)O(4) @SBC+O(3)) in enhancing the sludge dewaterability, the effectiveness in synchronized abatement antibiotics and antibiotic resistance genes (ARGs) was conducted to determine. The results revealed that catalytic ozonation conditioning altered the distribution of target antibiotics (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) in the dewatered filtrate, the dewatered sludge cake and the extra-microcolony/cellular polymers (EMPS/ECPS) layers, achieving the redistribution from solid-phase adsorption to liquid-phase dissolution. The total degradation rate was over 90% for TC and OTC, 72-78% for NOR and OFL; the abatement efficiency of eleven ARGs reached 1.47-3.01 log and 1.64-3.59 log, respectively, and more than four eARGs were eliminated. The effective abatement of the absolute abundance of Mobile genetic elements (MGEs) (0.91-1.89 log) demonstrated that catalytic ozonation conditioning could also significantly inhibit horizontal gene transfer (HGT). The abundance of resistant bacteria was greatly reduced and the signal transduction of the typical ARGs host bacteria was inhibited. The highly reactive oxidation species (ROS) generated were responsible for the abatement of antibiotics and ARGs. These findings provided new insights into the sludge conditioning for ideal and synchronized reduction in volume and hazardousness by catalytic ozonation processes in sludge treatment. | 2024 | 37944236 |
| 8054 | 1 | 0.9952 | Effects of nanoscale zero-valent iron on the performance and the fate of antibiotic resistance genes during thermophilic and mesophilic anaerobic digestion of food waste. The effects of nanoscale zero-valent iron (nZVI) on the performance of food waste anaerobic digestion and the fate of antibiotic resistance genes (ARGs) were investigated in thermophilic (TR) and mesophilic (MR) reactors. Results showed that nZVI enhanced biogas production and facilitated ARGs reduction. The maximum CH(4) production was 212.00 ± 4.77 ml/gVS with 5 g/L of nZVI in MR. The highest ARGs removal ratio was 86.64 ± 0.72% obtained in TR at nZVI of 2 g/L. nZVI corrosion products and their contribution on AD performance were analyzed. The abundance of tetracycline genes reduced significantly in nZVI amended digesters. Firmicutes, Chloroflexi, Proteobacteria and Spirochaetes showed significant positive correlations with various ARGs (p < 0.05) in MR and TR. Redundancy analysis indicated that microbial community was the main factor that influenced the fate of ARGs. nZVI changed microbial communities, with decreasing the abundance bacteria belonging to Firmicutes and resulting in the reduction of ARGs. | 2019 | 31505392 |
| 8058 | 2 | 0.9951 | Effects of biochars on the fate of antibiotics and their resistance genes during vermicomposting of dewatered sludge. It is currently still difficult to decrease the high contents of antibiotics and their corresponding antibiotic resistance genes (ARGs) in sludge vermicompost. To decrease the environmental risk of vermicompost as a bio-fertilizer, this study investigated the feasibility of biochar addition to decrease the levels of antibiotics and ARGs during vermicomposting of dewatered sludge. To achieve this, 1.25% and 5% of corncob and rice husk biochars, respectively, were added to sludge, which was then vermicomposted by Eisenia fetida for 60 days. The sludge blended with corncob biochar showed increased decomposition and humification of organic matter. Higher biochar concentration promoted both the number and diversity of bacteria, and differed dominant genera. The level of antibiotics significantly decreased as a result of biochar addition (P < 0.05), and tetracycline was completely removed. Relative to the control without addition of biochars, ermF and tetX genes significantly decreased with corncob biochar treatment (P < 0.05). Rice husk biochar (5%) could effectively decrease sul-1 and sul-2 genes in vermicompost (P < 0.05). However, the abundance of the intI-1 gene increased with biochar concentration. This study suggests that biochar addition can lessen the antibiotic and ARG pollution in sludge vermicompost, depending on the type and concentration of biochars. | 2020 | 32388093 |
| 7750 | 3 | 0.9949 | Efficient removal of enrofloxacin in swine wastewater using eukaryotic-bacterial symbiotic membraneless bioelectrochemical system. A eukaryotic-bacterial symbiotic membraneless bioelectrochemical system (EBES) reactor with eukaryotic-bacteria symbiotic cathode was developed to treat swine wastewater containing enrofloxacin (ENR), which had high performance at ENR tolerance and operational stability. With ENR concentrations shifting from 2 to 50 mg/L, the removal efficiencies of ENR, chemical oxygen demand (COD) and NH(4)(+)-N always were higher than 95 %, and the maximum power output (≥343 mW/m(3)) could be achieved. At 20 mg/L ENR, the removal efficiencies of ENR, COD and NH(4)(+)-N respectively reached to 99.4 ± 0.1 %, 98.5 % ± 0.1 %, and 96.3 % ± 0.5 %, corresponding to the open circuit voltage and maximum power density (P(max)) of EBES were 851 mV and 455 mW/m(3). The community analyses showed that bacteria (Comamonas, Rhodobacter, Rhodococcus, and Vermiphilaceae et al.), algae (Chlorella) and fungi (Rozellomycota, Trebouxiophyceae, Exophiala, and Aspergillus et al.) at genus level were the dominate populations in the EBES, and their abundance increased with ENR concentration, suggesting they played key roles to remove ENR and another nutrient element. The low relative abundances (1.9 ×10(-7) to 1.1 ×10(-5) copies/g) of aac (6')-ib-cr, qnrA, qnrD, qnrS, and gyrA in effluent revealed that the present EBES reactor had superior capabilities in controlling antibiotic-resistance genes and antibiotic-resistant bacteria. Our trial experiments provided a novel way for antibiotic livestock wastewater treatment. | 2025 | 39938376 |
| 7825 | 4 | 0.9949 | Comparison of different disinfection processes in the effective removal of antibiotic-resistant bacteria and genes. This study compared three different disinfection processes (chlorination, E-beam, and ozone) and the efficacy of three oxidants (H2O2, S2O(-)8, and peroxymonosulfate (MPS)) in removing antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in a synthetic wastewater. More than 30 mg/L of chlorine was needed to remove over 90% of ARB and ARG. For the E-beam method, only 1 dose (kGy) was needed to remove ARB and ARG, and ozone could reduce ARB and ARG by more than 90% even at 3 mg/L ozone concentration. In the ozone process, CT values (concentration × time) were compared for ozone alone and combined with different catalysts based on the 2-log removal of ARB and ARG. Ozone treatment yielded a value of 31 and 33 (mg·min)/L for ARB and ARGs respectively. On the other hand, ozone with persulfate yielded 15.9 and 18.5 (mg·min)/L while ozone with monopersulfate yielded a value of 12 and 14.5 (mg·min)/L. This implies that the addition of these catalysts significantly reduces the contact time to achieve a 2-log removal, thus enhancing the process in terms of its kinetics. | 2014 | 25079831 |
| 7745 | 5 | 0.9948 | Iron-modified biochar boosts anaerobic digestion of sulfamethoxazole pharmaceutical wastewater: Performance and microbial mechanism. The accumulation of volatile fatty acids (VFAs) caused by antibiotic inhibition significantly reduces the treatment efficiency of sulfamethoxazole (SMX) wastewater. Few studies have been conducted to study the VFAs gradient metabolism of extracellular respiratory bacteria (ERB) and hydrogenotrophic methanogen (HM) under high-concentration sulfonamide antibiotics (SAs). And the effects of iron-modified biochar on antibiotics are unknown. Here, the iron-modified biochar was added to an anaerobic baffled reactor (ABR) to intensify the anaerobic digestion of SMX pharmaceutical wastewater. The results demonstrated that ERB and HM were developed after adding iron-modified biochar, promoting the degradation of butyric, propionic and acetic acids. The content of VFAs reduced from 1166.0 mg L(-1) to 291.5 mg L(-1). Therefore, chemical oxygen demand (COD) and SMX removal efficiency were improved by 22.76% and 36.51%, and methane production was enhanced by 6.19 times. Furthermore, the antibiotic resistance genes (ARGs) such as sul1, sul2, intl1 in effluent were decreased by 39.31%, 43.33%, 44.11%. AUTHM297 (18.07%), Methanobacterium (16.05%), Geobacter (6.05%) were enriched after enhancement. The net energy after enhancement was 0.7122 kWh m(-3). These results confirmed that ERB and HM were enriched via iron-modified biochar to achieve high efficiency of SMX wastewater treatment. | 2023 | 37030222 |
| 8055 | 6 | 0.9948 | Effects of nano-zerovalent iron on antibiotic resistance genes during the anaerobic digestion of cattle manure. This study investigated the effects of adding nano-zerovalent iron (nZVI) at three concentrations (0, 80, and 160 mg/L) on the methane yield and the fate of antibiotic resistance genes (ARGs) during the anaerobic digestion (AD) of cattle manure. The addition of nZVI effectively enhanced the methane yield, where it significantly increased by 6.56% with 80 mg/L nZVI and by 6.43% with 160 mg/L nZVI. The reductions in the abundances of ARGs and Tn916/1545 were accelerated by adding 160 mg/L nZVI after AD. Microbial community analysis showed that nZVI mainly increased the abundances of bacteria with roles in hydrolysis and acidogenesis, whereas it reduced the abundance of Acinetobacter. Redundancy analysis indicated that the changes in mobile genetic elements made the greatest contribution to the fate of ARGs. The results suggest that 160 mg/L nZVI is a suitable additive for reducing the risks due to ARGs in AD. | 2019 | 31247529 |
| 8050 | 7 | 0.9948 | Effects of antibiotics on corncob supported solid-phase denitrification: Denitrification and antibiotics removal performance, mechanism, and antibiotic resistance genes. Solid-phase denitrification (SPD) has been used in wastewater treatment plant effluent to enhance nitrate removal, and antibiotics co-existing in the effluent is a common environmental problem. In this study, it was systematically investigated the effect of single trace sulfamethoxazole (SMX)/trimethoprim (TMP) and their mixture on microbial denitrification performance, the antibiotics removal, and antibiotics resistance genes (ARGs) in corncob supported SPD system. The average denitrification rate was improved by 46.90% or 61.09% with single 50 µg/L SMX or TMP, while there was no significant inhibition with mixed SMX and TMP. The abundance of dominant denitrifiers (Comamonadaceae family and Azospia) and fermentation bacteria (Ancalomicrobium) were consistent with the denitrification performance of different antibiotics groups. Single SMX and TMP achieved relatively higher denitrification gene and enzyme abundance. Mixed SMX and TMP improved the denitrification gene copies, but they reduced the key denitrification enzymes except for EC 1.7.7.2. Additionally, the removal efficiency of TMP (56.70% ± 3.18%) was higher than that of SMX (25.44% ± 2.62%) in single antibiotic group, and the existence of other antibiotics (i.e. SMX or TMP) had no significant impact on the TMP or SMX removal performance. Biodegradation was the main removal mechanism of SMX and TMP, while sludge and corncob adsorption contributed a little to their removal. SMX had the risk of sulfanilamide resistance genes (SRGs) dissemination. Furthermore, network analysis indicated that Niveibacterium and Bradyrhizobium were the potential hosts of SRGs, which promoted the horizontal transmission of ARGs. | 2023 | 37032040 |
| 7922 | 8 | 0.9948 | Simultaneous removal and high tolerance of norfloxacin with electricity generation in microbial fuel cell and its antibiotic resistance genes quantification. Norfloxacin (NFLX) is a synthetic antibiotic widely used in the treatment of infectious diseases. In this work, the performance of microbial fuel cells (MFCs) toward NFLX degradation, electricity production and the antibiotics resistances genes (ARGs) generation was investigated. NFLX degradation efficiency and COD removal reached 65.5% and 94.5% respectively. The increase in NFLX concentration (128 mg/L) had no significant influence on NFLX degradation efficiency, COD removal and MFCs voltage output while the electricity was successfully generated. The quantitative polymerase chain reaction (qPCR) indicated low absolute abundances of ARGs (mdtk, mdtm, and pmra) compared with the traditional wastewater treatment plants (WWTPs). Anodic bacteria can survive in the presence of high NFLX concentration and sustain its degradation and electricity production. In terms of NFLX degradation, COD removal, diminished ARGs generation and simultaneous energy production, MFC seems to be a promising technology for antibiotics wastewater treatment with a potential to overcome the ARGs challenge. | 2020 | 32097778 |
| 8056 | 9 | 0.9948 | Antibiotic resistance gene profiles and evolutions in composting regulated by reactive oxygen species generated via nano ZVI loaded on biochar. In this study, nano zero-valent iron loaded on biochar (BC-nZVI) was analyzed for its effects on antibiotic resistance genes (ARGs) in composting. The results showed that BC-nZVI increased reactive oxygen species (ROS) production, and the peak values of H(2)O(2) and OH were 22.95 % and 55.30 % higher than those of the control group, respectively. After 65 days, the relative abundances of representative ARGs decreased by 56.12 % in the nZVI group (with BC-nZVI added). An analysis of bacterial communities and networks revealed that Actinobacteria, Proteobacteria, and Firmicutes were the main hosts for ARGs, and BC-nZVI weakened the link between ARGs and host bacteria. Distance-based redundancy analysis showed that BC-nZVI altered the microbial community structure through environmental factors and that most ARGs were negatively correlated with ROS, suggesting that ROS significantly affected the relative abundance of ARGs. According to these results, BC-nZVI showed potential for decreasing the relative abundance of ARGs in composting. | 2023 | 37611721 |
| 8057 | 10 | 0.9948 | SiO(2) nanoparticles can enhance nitrogen retention and reduce copper resistance genes during aerobic composting of swine manure. SiO(2) nanoparticles (SiO(2) NPs) are low-cost, environmentally friendly materials with significant potential to remove pollutants from complex environments. In this study, SiO(2) NPs were used for the first time as an additive in aerobic composting to enhance nitrogen retention and reduce the expression of copper resistance genes. The addition of 0.5 g kg(-1) SiO(2) NPs effectively reduced nitrogen loss by 72.33 % by decreasing denitrification genes (nosZ, nirK, and napA) and increasing nitrogen fixation gene (nifH). The dominant factors affecting nitrification and denitrification genes were Firmicutes and C/N ratio. Additionally, SiO(2) NPs decreased copper resistance genes by 28.96 % - 37.52 % in compost products. Copper resistance genes decreased most in the treatment with 0.5 g kg(-1) SiO(2) NPs. In summary, 0.5 g kg(-1) SiO(2) NPs have the potential to reduce copper resistance genes and enhance nitrogen retention during aerobic composting, which may be used to improve compost quality. | 2024 | 39374833 |
| 7792 | 11 | 0.9947 | Comparative 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. | 2021 | 33059146 |
| 7988 | 12 | 0.9947 | Electrokinetic treatment at the thermophilic stage achieves more effective control of heavy metal resistance in swine manure composting. Excessive heavy metals (HMs) and metal resistance genes (MRGs) in manure pose significant environmental and human health risks. Our previous work proved enhanced control of antibiotic resistance and quality of swine manure composting with electrokinetic technology (EK). As a continuous study, EK treatments were further employed at typical stages of composting. The humification level increased significantly in EK treatments applied at the thermophilic stage (EK1) and throughout the whole composting period (EK2). The immobilization efficiency of heavy metals increased by 3.02 %-20.90 % for EK1, and 3.86 %-20.56 % for EK2, compared with the EK treatment applied at maturity stage (EK3). EK1 showed the highest ability to remove MRGs (29.38 %-87.13 %), while the abundance of potential host bacteria increased in EK2, raising potential transmission risk of MRGs. Furthermore, there was an elevated presence of bacteria associated with membrane transport as a response mechanism to HMs stress in EK1. Considering economic factors and environmental effects, EK treatment during the thermophilic stage was more effective in compost maturation, HMs passivation, as well as control of HMs resistance. This study provides an effective method to address HMs-related contamination with highly efficient maturation in swine manure composting. | 2025 | 40543370 |
| 7876 | 13 | 0.9946 | Sulfamethoxazole impact on pollutant removal and microbial community of aerobic granular sludge with filamentous bacteria. In this study, sulfamethoxazole (SMX) was employed to investigate its impact on the process of aerobic granule sludge with filamentous bacteria (FAGS). FAGS has shown great tolerance ability. FAGS in a continuous flow reactor (CFR) could keep stable with 2 μg/L of SMX addition during long-term operation. The NH(4)(+), chemical oxygen demand (COD), and SMX removal efficiencies kept higher than 80%, 85%, and 80%, respectively. Both adsorption and biodegradation play important roles in SMX removal for FAGS. The extracellular polymeric substances (EPS) might play important role in SMX removal and FAGS tolerance to SMX. The EPS content increased from 157.84 mg/g VSS to 328.22 mg/g VSS with SMX addition. SMX has slightly affected on microorganism community. A high abundance of Rhodobacter, Gemmobacter, and Sphaerotilus of FAGS may positively correlate to SMX. The SMX addition has led to the increase in the abundance of the four sulfonamide resistance genes in FAGS. | 2023 | 36871701 |
| 8007 | 14 | 0.9946 | Distinguishing removal and regrowth potential of antibiotic resistance genes and antibiotic resistant bacteria on microplastics and in leachate after chlorination or Fenton oxidation. The prevalence of antibiotic resistance, as well as microplastics (MPs) as vectors for antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has attracting growing attention. However, the fate of ARB/ARGs on MPs treated by chlorination and Fenton oxidation were poorly understood. Herein, the removal and regrowth of ARGs/ARB on MPs and in MPs-surrounding landfill leachate (an important reservoir of MPs and ARGs) after chlorination and Fenton oxidation were comparatively analyzed. Target ARGs on MPs were reduced obviously less than that in leachate, with the largest percentages reduction of 34.0-46.3% vs. 54.3-77.6% after chlorination and 92.1-97.3% vs. > 99.9% after Fenton oxidation, and similar removal patterns were observed for ARB. Moreover, a considerable regrowth of ARGs/ARB in leachate were found after 48 h of storage at the end of chlorination (5, 10, 20 and 50 mg/L), and a greater regrowth of ARGs and ARB occurred on MPs with up to 17 and 139 fold, respectively. In contrast, Fenton oxidation achieved a reduced regrowth of target ARGs/ARB. These findings indicated that the removal of ARGs/ARB on MPs were more difficult than that in leachate, and ARGs/ARB in leachate and especially on MPs exhibited a considerable potential for rapid regrowth after chlorination. | 2022 | 35158247 |
| 7861 | 15 | 0.9946 | The removal of antibiotic resistant bacteria and genes and inhibition of the horizontal gene transfer by contrastive research on sulfidated nanoscale zerovalent iron activating peroxymonosulfate or peroxydisulfate. Antibiotic resistant bacteria (ARB) and the antibiotic resistance genes (ARGs) dissemination via plasmid-mediated conjugation have attracted considerable attentions. In this research, sulfidated nanoscale zerovalent iron (S-nZVI)/peroxymonosulfate (PMS) and S-nZVI/peroxydisulfate (PDS) process were investigated to inactivate ARB (Escherichia coli DH5α with RP4 plasmid, Pseudomonas. HLS-6 contains sul1 and intI1 on genome DNA sequence). S-nZVI/PMS system showed higher efficiency than S-nZVI/PDS on ARB inactivation. Thus, the optimal condition 28 mg/L S-nZVI coupled with 153.7 mg/L (0.5 mM) PMS was applied to remove both intracellular ARGs (iARGs) and ARB. The oxidative damage of ARB cell was systemically studied by cell viability, intracellular Mg(2+) levels, the changes of extracellular and internal structure, integrity of cell walls and membranes and enzymatic activities. S-nZVI/PMS effectively inactivated ARB (~7.32 log) within 15 min. These effects were greatly higher than those achieved individually. Moreover, removal efficiencies of iARGs sul1, intI1 and tetA were 1.52, 1.79 and 1.56 log, respectively. These results revealed that S-nZVI and PMS have a synergistic effect against ARB and iARGs. The regrowth assays illustrated that the ARB were effectively inactivated. By verifying the inhibitory impacts of S-nZVI/PMS treatment on conjugation transfer, this work highlights a promising alternative technique for inhibiting the horizontal gene transfer. | 2022 | 34482079 |
| 7923 | 16 | 0.9946 | Effect of ultrasonic and ozone pretreatment on the fate of enteric indicator bacteria and antibiotic resistance genes, and anaerobic digestion of dairy wastewater. In this study, the effect of ultrasound (US), ozone and US combined with ozone (US/ozone) pretreatments on the fate of enteric indicator bacteria and antibiotic resistance genes (ARGs), and anaerobic digestion (AD) of dairy wastewater was investigated. The pretreatment conditions included US power 200 W, ozone concentration 4.2 mg O(3)/L, and pretreatment time 0-30 min. The results showed that US/ozone pretreatment was effective in the inactivation of enteric indicator bacteria. Total coliforms and enterococci were reduced by 99% and 92% after 30 min US/ozone pretreatment. Pretreatments could not decrease ARGs in absolute concentration, but could decrease ARGs in relative abundance. In the subsequent AD process, methane production increased more than 10% with 20 min ozone or 20 min US/ozone pretreatments. Pretreatment-AD together obviously inhibited the enrichment of ARGs in relative abundance. This study provided a pretreatment way to enhance methane production and to prevent the enrichment of ARGs. | 2021 | 33186838 |
| 8112 | 17 | 0.9946 | Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment. The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency. | 2016 | 26970692 |
| 8110 | 18 | 0.9946 | Removal of chlortetracycline and antibiotic resistance genes in soil by earthworms (epigeic Eisenia fetida and endogeic Metaphire guillelmi). The impacts of two ecological earthworms on the removal of chlortetracycline (CTC, 0.5 and 15 mg kg(-1)) and antibiotic resistance genes (ARGs) in soil were explored through the soil column experiments. The findings showed that earthworm could significantly accelerate the degradation of CTC and its metabolites (ECTC) in soil (P < 0.05), with epigeic Eisenia fetida promoting degradation rapidly and endogeic Metaphire guillelmi exhibiting a slightly better elimination effect. Earthworms alleviated the abundances of tetR, tetD, tetPB, tetG, tetA, sul1, TnpA, ttgB and intI1 in soil, with the total relative abundances of ARGs decreasing by 35.0-44.2% in earthworm treatments at the 28th day of cultivation. High throughput sequencing results displayed that the structure of soil bacteria community was modified apparently with earthworm added, and some possible CTC degraders, Aeromonas, Flavobacterium and Luteolibacter, were promoted by two kinds of earthworms. Redundancy analysis demonstrated that the reduction of CTC residues, Actinobacteria, Acidobacteria and Gemmatimonadetes owing to earthworm stimulation was responsible for the removal of ARGs and intI1 in soil. Additionally, intI1 declined obviously in earthworm treatments, which could weaken the risk of horizontal transmission of ARGs. Therefore, earthworm could restore the CTC-contaminated soil via enhancing the removal of CTC, its metabolites and ARGs. | 2021 | 33798888 |
| 8045 | 19 | 0.9946 | Correlation among extracellular polymeric substances, tetracycline resistant bacteria and tetracycline resistance genes under trace tetracycline. Antibiotic resistance occurrences and proliferation in activated sludge have attracted more and more attention nowadays. However, the role which extracellular polymeric substance (EPS) plays on the antibiotic resistance is not clear. The changes and correlation among EPS, tetracycline (TC) resistant bacteria (TRB) and TC resistance genes (TRGs) of sequencing batch reactors (SBRs) were investigated. Performance of SBR without TC was compared with two other SBRs to which different amounts of TC were added. Total average EPS contents were found to increase significantly from 66 mg g−1 VSS to 181 mg g−1 VSS as the TC concentrations increased from 0 to 100 μg L−1. As the EPS content increased, TRB in sludge of the three SBRs increased significantly from 105 to 106 colony forming unit mL−1 after being exposed to TC. In addition, the concentrations of three groups of TRGs (copies mL−1) were determined by real-time fluorescence quantitative polymerase chain reaction and followed the order: efflux pump genes > ribosome protected genes > degradation enzyme genes. The numbers of TRGs in the idle stage were larger than those in the aeration sludge. Correlation coefficients (R2) between EPS and TRB in sludge were 0.823 (p < 0.01) while the correlation between EPS and total TRGs was poor (R2 = 0.463, p > 0.05). But it showed the same tendency that EPS and TRGs in sludge increased with the increasing of TC. | 2014 | 25461932 |