# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 7802 | 0 | 0.9571 | Inactivating facultative pathogen bacteria and antibiotic resistance genes in wastewater using blue light irradiation combined with a photosensitizer and hydrogen peroxide. The effectiveness of antimicrobial blue light (aBL) irradiation in eliminating ten clinically significant antibiotic resistance genes (ARGs) and four taxonomic marker genes of the WHO-priority ESKAPE bacteria group from wastewater treatment plant (WWTP) effluent was examined. Experiments were conducted using an LED-driven continuous-flow photoreactor operating at wavelengths of 405 nm, 420 nm, and 460 nm. Irradiation with aBL alone was insufficient for effectively inactivating or eliminating ESKAPE bacteria and clinically relevant ARGs. The addition of the porphyrin-based photosensitizer TMPyP (10(-6) M) or the oxidative agent H₂O₂ (1 mM) resulted in several log(10) unit reductions of facultative pathogenic bacteria (FPB), their taxonomic gene markers, and target ARGs. However, the additional effects of TMPyP and H(2)O(2) were only noticeable in conjunction with aBL irradiation, as they were ineffective without it. The reduction of the different FPB and ARGs in WWTP effluents was analyzed using culturing and qPCR together with living/dead discrimination. Different FPB and ARGs showed varying susceptibility to aBL-mediated irradiation. Among the FPB, enterococci were the most sensitive, while among the ARGs bacteria carrying ermB, tetM, sul1, and bla(VIM) genes exhibited the strongest removal. This sensitivity may be due to the gene-carrying microorganism's response to aBL irradiation combined with TMPyP or H(2)O(2). Additionally, molecular biology results revealed that aBL irradiation induced up to 13 lesions per 10 kb DNA, which is hypothesized to contribute to the acute inactivation effect and prevent regrowth by inhibiting DNA repair activities. | 2025 | 40138903 |
| 7306 | 1 | 0.9570 | Impact of the particulate matter from wastewater discharge on the abundance of antibiotic resistance genes and facultative pathogenic bacteria in downstream river sediments. Wastewater treatment plants (WWTPs) are point sources for both, the release of antibiotic resistance genes (ARGs) and the discharge of antibiotics (ABs) into the environment. While it is well established that ARGs emission by WWTPs leads to an ARGs increase in receiving rivers, also the role of sub-inhibitory AB concentrations in this context is being discussed. However, the results obtained in this study suggest that, at environmental concentrations, ABs do not have an effect on resistance selection. Instead, we emphasize the significance of ARG transport and, in that respect, highlight the relevance of wastewater particles and associated microorganisms. We can show that ARGs (ermB, bla(TEM,)tetM, qnrS) as well as facultative pathogenic bacteria (FPB) (enterococci, Pseudomonas aeruginosa, Acinetobacter baumannii) inside the particulate fraction of WWTP effluent are very likely to remain in the riverbed of the receiving water due to sedimentation. Moreover, ARG and FPB abundances measured in the particulate fraction strongly correlated with the delta ARG and FPB abundances measured in the receiving river sediment (downstream compared to upstream) (R(2) = 0.93, p < 0.05). Apparently, the sheer amount of settleable ARGs and FPB from WWTP effluent is sufficient, to increase abundances in the receiving riverbed by 0.5 to 2 log units. | 2019 | 30308888 |
| 7273 | 2 | 0.9560 | Evaluation of antibiotic resistance dissemination by wastewater treatment plant effluents with different catchment areas in Germany. The study quantified the abundances of antibiotic resistance genes (ARGs) and facultative pathogenic bacteria (FPB) as well as one mobile genetic element in genomic DNA via qPCR from 23 different wastewater treatment plant (WWTP) effluents in Germany. 12 clinically relevant ARGs were categorized into frequently, intermediately, and rarely occurring genetic parameters of communal wastewaters. Taxonomic PCR quantifications of five FPB targeting Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and enterococci were performed. The WWTPs differed in their catchment areas being impacted by hospitals, food processing companies, or housing areas only. The total discharges of the analyzed ARGs and FPB were found to cluster independently of the sizes of the WWTPs with a maximum difference of two log units within one cluster. Initially, quantitative data evaluations revealed no significant difference between ARG categories and WWTP catchment areas. More distinct correlations became obvious with a Pearson correlation approach, where each single taxonomic marker is compared to each ARG target. Here, increased correlation of FPB (i.e. E. coli, K. pneumoniae, P. aeruginosa, and enterococci) with clinically relevant ARGs of the category of rarely occurring resistance genes (bla(NDM-1), vanA) was found in WWTP effluents being influenced by hospital wastewaters. | 2020 | 32488142 |
| 7277 | 3 | 0.9554 | Occurrence and persistence of carbapenemases genes in hospital and wastewater treatment plants and propagation in the receiving river. This study aims to investigate the prevalence of clinically relevant carbapenemases genes (bla(KPC), bla(NDM) and bla(OXA-48)) in water samples collected over one-year period from hospital (H), raw and treated wastewater of two wastewater treatment plants (WWTPs) as well as along the Zenne River (Belgium). The genes were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that absolute abundances were the highest in H waters. Although absolute abundances were significantly reduced in WWTP effluents, the relative abundance (normalized per 16S rRNA) was never lowered through wastewater treatment. Particularly, for the PAB the relative abundances were significantly higher in the effluents respect to the influents of both WWTPs for all the genes. The absolute abundances along the Zenne River increased from upstream to downstream, peaking after the release of WWTPs effluents, in both fractions. Our results demonstrated that bla(KPC), bla(NDM) and bla(OXA-48) are widely distributed in the Zenne as a consequence of chronic discharge from WWTPs. To conclude, the levels of carbapenemases genes are significantly lower than other genes conferring resistance to more widely used antibiotics (analyzed in previous studies carried out at the same sites), but could raise up to the levels of high prevalent resistance genes. | 2018 | 29960932 |
| 7276 | 4 | 0.9553 | Antibiotic resistance in urban and hospital wastewaters and their impact on a receiving freshwater ecosystem. The main objective of this study was to investigate the antibiotic resistance (AR) levels in wastewater (WW) and the impact on the receiving river. Samples were collected once per season over one year in the WW of a hospital, in the raw and treated WW of two wastewater treatment plants (WWTPs), as well as upstream and downstream from the release of WWTPs effluents into the Zenne River (Belgium). Culture-dependent methods were used to quantify Escherichia coli and heterotrophic bacteria resistant to amoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. Six antibiotic resistance genes (ARGs) were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that WWTPs efficiently removed antibiotic resistant bacteria (ARB) regardless of its AR profile. The ARGs levels were the highest in the hospital WW and were significantly reduced in both WWTPs. However, ARB and ARGs abundances significantly increased into the Zenne River downstream from the WWTPs outfalls. The variation in the relative abundance of ARGs through WW treatment differed depending on the WWTP, fraction, and gene considered. The sul1 and sul2 genes in PAB fraction showed significantly higher relative abundances in the effluent compared to the influent of both WWTPs. This study demonstrated that WWTPs could be hotspots for AR spread with significant impacts on receiving freshwater ecosystems. This was the first comprehensive study investigating at the same time antibiotics occurrence, fecal bacteria indicators, heterotrophic bacterial communities, and ARGs (distinguishing PAB and FLB) to assess AR levels in WW and impacts on the receiving river. | 2018 | 29730567 |
| 8112 | 5 | 0.9553 | 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 |
| 7811 | 6 | 0.9553 | Removal of Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes Affected by Varying Degrees of Fouling on Anaerobic Microfiltration Membranes. An anaerobic membrane bioreactor was retrofitted with polyvinylidene fluoride (PVDF) microfiltration membrane units, each of which was fouled to a different extent. The membranes with different degrees of fouling were evaluated for their efficiencies in removing three antibiotic-resistant bacteria (ARB), namely, bla(NDM-1)-positive Escherichia coli PI-7, bla(CTX-M-15)-positive Klebsiella pneumoniae L7, and bla(OXA-48)-positive E. coli UPEC-RIY-4, as well as their associated plasmid-borne antibiotic resistance genes (ARGs). The results showed that the log removal values (LRVs) of ARGs correlated positively with the extent of membrane fouling and ranged from 1.9 to 3.9. New membranes with a minimal foulant layer could remove more than 5 log units of ARB. However, as the membranes progressed to subcritical fouling, the LRVs of ARB decreased at increasing operating transmembrane pressures (TMPs). The LRV recovered back to 5 when the membrane was critically fouled, and the achieved LRV remained stable at different operating TMPs. Furthermore, characterization of the surface attributed the removal of both the ARB and ARGs to adsorption, which was facilitated by an increasing hydrophobicity and a decreasing surface ζ potential as the membranes fouled. Our results indicate that both the TMP and the foulant layer synergistically affected ARB removal, but the foulant layer was the main factor that contributed to ARG removal. | 2017 | 28957626 |
| 7755 | 7 | 0.9552 | Anthropogenic impacts on sulfonamide residues and sulfonamide resistant bacteria and genes in Larut and Sangga Besar River, Perak. The environmental reservoirs of sulfonamide (SA) resistome are still poorly understood. We investigated the potential sources and reservoir of SA resistance (SR) in Larut River and Sangga Besar River by measuring the SA residues, sulfamethoxazole resistant (SMX(r)) in bacteria and their resistance genes (SRGs). The SA residues measured ranged from lower than quantification limits (LOQ) to 33.13 ng L(-1) with sulfadiazine (SDZ), sulfadimethoxine (SDM) and SMX as most detected. Hospital wastewater effluent was detected with the highest SA residues concentration followed by the slaughterhouse and zoo wastewater effluents. The wastewater effluents also harbored the highest abundance of SMX(r)-bacteria (10(7) CFU mL(-1)) and SRGs (10(-1)/16S copies mL(-1)). Pearson correlation showed only positive correlation between the PO(4) and SMX(r)-bacteria. In conclusion, wastewater effluents from the zoo, hospital and slaughterhouse could serve as important sources of SA residues that could lead to the consequent emergence of SMX(r)-bacteria and SRGs in the river. | 2019 | 31726563 |
| 8000 | 8 | 0.9551 | Fate of antibiotic resistance genes in reclaimed water reuse system with integrated membrane process. The fate of antibiotic resistance genes (ARGs) in reclaimed water reuse system with integrated membrane process (IMR) was firstly investigated. Results indicated that ARGs, class 1 integrons (intI1) and 16S rRNA gene could be reduced efficiently in the IMR system. The absolute abundance of all detected ARGs in the reuse water after reverse osmosis (RO) filtration of the IMR system was 4.03 × 10(4) copies/mL, which was about 2-3 orders of magnitude lower than that in the raw influent of the wastewater treatment plants (WWTPs). Maximum removal efficiency of the detected genes was up to 3.8 log removal values. Daily flux of the summation of all selected ARGs in the IMR system decreased sharply to (1.02 ± 1.37) ×10(14) copies/day, which was 1-3 orders of magnitude lower than that in the activated sludge system (CAS) system. The strong clustering based on ordination analysis separated the reuse water from other water samples in the WWTPs. Network analysis revealed the existence of potential multi-antibiotic resistant bacteria. The potential multi-antibiotic resistant bacteria, including Clostridium and Defluviicoccus, could be removed effectively by microfiltration and RO filtration. These findings suggested that the IMR system was efficient to remove ARGs and potential multi-antibiotic resistant bacteria in the wastewater reclamation system. | 2020 | 31446351 |
| 7272 | 9 | 0.9549 | Determination of antibiotic resistance genes in a WWTP-impacted river in surface water, sediment, and biofilm: Influence of seasonality and water quality. Many pathogenic bacteria are adapted to live in aquatic habitats, which makes rivers possible sources and spread pathways of antibiotic resistance, since they usually receive effluents from wastewater treatment plants (WWTP), possibly containing antibiotic residues and also antibiotic-resistant bacteria. This study investigates different monitoring strategies to identify the occurrence of antibiotic-resistant bacteria in rivers. We analyzed the presence of 13 antibiotic resistance genes (ARGs) and seven gene markers for facultative pathogenic bacteria (FPB) with qPCR in sampling sites upstream and downstream of a small WWTP in Southern Germany. Five sampling campaigns were conducted from February to June 2019. Surface water, sediment, and biofilm samples were analyzed. The biofilm was collected from an artificial sampler placed in the river. bla(TEM), ermB, tetM, and sul1 genes were detected in all samples analyzed. The results showed there was a previous background in the river, but the WWTP and the water quality of the river influenced the concentration and occurrence of ARGs and FPB. Genes representing resistance against strong or last-resort antibiotics, such as mecA, bla(CMY-2), bla(KPC-3), and mcr-1, and multidrug resistance were also detected, mainly in samples collected downstream of the WWTP. Downstream of the WWTP, the occurrence of ARG and FPB correlated with ammoniacal nitrogen, while upstream of the WWTP correlated with turbidity, suspended solids, and seasonal factors such as UVA radiation and the presence of macrophytes. Biofilm samples presented higher abundances of ARGs and FPB. The biofilm sampler was efficient and allowed to collect biofilms from specific periods, which helped to identify seasonal patterns. | 2021 | 33450684 |
| 7796 | 10 | 0.9548 | Irreversible inactivation of carbapenem-resistant Klebsiella pneumoniae and its genes in water by photo-electro-oxidation and photo-electro-Fenton - Processes action modes. Carbapenem-resistant Klebsiella pneumoniae is a critical priority pathogen according to the World Health Organization's classification. Effluents of municipal wastewater treatment plants (EWWTP) may be a route for K. pneumoniae dissemination. Herein, the inactivation of this microorganism in simulated EWWTP by the photo-electro-oxidation (PEO) and photo-electro-Fenton (PEF) processes was evaluated. Firstly, the disinfecting ability and action pathways of these processes were established. PEO achieved faster K. pneumoniae inactivation (6 log units in 75 min of treatment) than the PEF process (6 log units in 105 min of treatment). PEO completely inactivated K. pneumoniae due to the simultaneous action of UVA light, electrogenerated H(2)O(2,) and anodic oxidation pathways. The slower inactivation of K. pneumoniae when using PEF was related to interfering screen effects of iron oxides on light penetration and the diffusion of the bacteria to the anode. However, both PEO and PEF avoided the recovery and regrowth of treated bacteria (with no detectable increase in the bacteria concentration after 24 h of incubation). In addition to the bacteria evolution, the effect of treatment processes on the resistance gene was examined. Despite inactivation of K. pneumoniae by PEF was slower than by PEO, the former process induced a stronger degrading action on the gene, conferring the resistance to carbapenems (PEF had a Ct value of 24.92 cycles after 105 min of treatment, while PEO presented a Ct of 19.97 cycles after 75 min). The results of this research indicate that electrochemical processes such as PEO and PEF are highly effective at dealing with resistant K. pneumoniae in the EWWTP matrix. | 2021 | 34146813 |
| 7443 | 11 | 0.9548 | Wastewater pollution differently affects the antibiotic resistance gene pool and biofilm bacterial communities across streambed compartments. Wastewater discharges introduce antibiotic residues and antibiotic-resistant bacteria (ARB) into surface waters. Both inputs directly affect the streambed resistome, either by exerting a selective pressure that favour the proliferation of resistant phenotypes or by enriching the resident communities with wastewater-associated ARB. Here, we investigated the impact of raw and treated urban wastewater discharges on epilithic (growing on rocks) and epipsammic (growing on sandy substrata) streambed biofilms. The effects were assessed by comparing control and impact sites (i) on the composition of bacterial communities; (ii) on the abundance of twelve antibiotic resistance genes (ARGs) encoding resistance to β-lactams, fluoroquinolones, sulphonamides, tetracyclines, macrolides and vancomycin, as well as the class 1 integron-integrase gene (intI1); (iii) on the occurrence of wastewater-associated bacteria, including putative pathogens, and their potential linkage to target ARGs. We measured more pronounced effects of raw sewage than treated wastewater at the three studied levels. This effect was especially noticeable in epilithic biofilms, which showed a higher contribution of wastewater-associated bacteria and ARB than in epipsammic biofilms. Comparison of correlation coefficients obtained between the relative abundance of both target ARGs and operational taxonomic units classified as either potential pathogens or nonpathogens yielded significant higher correlations between the former category and genes intI1, sul1, sul2 and ermB. Altogether, these results indicate that wastewater-associated micro-organisms, including potential pathogens, contribute to maintain the streambed resistome and that epilithic biofilms appear as sensitive biosensors of the effect of wastewater pollution in surface waters. | 2017 | 28792642 |
| 6990 | 12 | 0.9548 | Metagenomics analysis of antibiotic resistance genes, the bacterial community and virulence factor genes of fouled filters and effluents from household water purifiers in drinking water. The aim of this study was to explore the influence and removal of household water purifiers (HWPs) on emerging contaminants in drinking water, and their distribution characteristics. The antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), virulence factor genes (VFGs) and bacterial communities were profiled in the fouled filters, influents, and effluents from HWPs with five steps of filtration after 150 days operation, using metagenomics. The results showed that the diversity of dominant species in Poly Propylene 1 μm (PP1) and nanofiltration membrane (NM) was significantly higher than that in other filters. Post-activated carbon (AC) was used to detect low species richness or diversity, and the highest proportion of dominant species, which contributes to the greater microbial risk of HWPs effluents in drinking water. The number of dominant bacterial genera in the filters disinfected with chloramine was higher than that in the same group disinfected with chlorine. The bacterial species richness or diversity in water was reduced by the purification of HWPs because the filter elements effectively trapped a variety of microorganisms. The relative abundance of Antibiotic efflux in the effluents of chlorinated and chloraminated HWPs was 5.58 × 10(-3) and 4.60 × 10(-3), respectively, which was the main resistance mechanism. High abundance of VFGs was found in HWPs effluents and the relative abundance of aggressive VFGs was significantly higher than those of defensive VFGs. Based on the co-occurrence results, 243 subtypes of ARGs co-occurred with VFGs, and a variety of bacteria were thought to be possible ARGs hosts, which indicated that the host bacteria of VFGs in HWP effluents had a stronger attack ability. The effluent of HWPs with only filtration processes is exposed to the risk of ARGs and VFGs. This study helps to understand the actual purification effect of HWPs and provides a theoretical reference for the management and control of ARGs pollution in domestic drinking water. | 2023 | 36075417 |
| 7178 | 13 | 0.9547 | Reduction of erythromycin resistance gene erm(F) and class 1 integron-integrase genes in wastewater by Bardenpho treatment. Wastewaters routinely contain antibiotic-resistant bacteria (ARB) and genes (ARG) that are removed to a varying degree during wastewater treatment. This study investigated the removal of the erythromycin ribosome methylase class F (erm(F)) and class 1 integron-integrase (intI1) genes at each stage from two water resource recovery facilities in southern Arizona. Although genes were significantly reduced by Bardenpho treatment, erm(F) and intI1 were still observed in ≥ 9 and 7 out of 12 secondary effluent samples. Primary processes via sedimentation or dissolved air flotation, as well as chlorine disinfection, did not significantly impact erm(F) and intI1 concentrations. Therefore, Bardenpho treatment was critical to reduce erm(F) and intI1. Concentrations of erm(F) and intI1 were compared with each other and other markers for anthropogenic pollution. Results from this study support intI1 as one suitable marker to measure erythromycin resistance genes in wastewater, as intI1 was found at higher concentrations, persisted more throughout treatment, and correlated with erm(F) at nearly every treatment stage. PRACTITIONER POINTS: Bardenpho treatment was the key process responsible for the reduction of intI1 and erm(F) genes during wastewater treatment. Primary treatment and chlorine disinfection did not impact erm(F) and intI1 gene concentrations. The intI1 gene is a suitable marker for measuring erm(F) genes in wastewater. | 2020 | 31989707 |
| 7758 | 14 | 0.9546 | Removal efficiency of antibiotic residues, antibiotic resistant bacteria, and genes across parallel secondary settling tank and membrane bioreactor treatment trains in a water reclamation plant. Antimicrobial resistance is recognized as a potent threat to human health. Wastewater treatment facilities are viewed as hotspots for the spread of antimicrobial resistance. This study provides comprehensive data on the occurrences of 3 different antibiotic resistant opportunistic pathogens (with resistance to up to 5 antibiotics), 13 antibiotic resistant genes and intI1, and 22 different antimicrobial residues in a large water reclamation plant (176 million gallons per day) that runs a conventional Modified Ludzack-Ettinger (MLE) reactor followed by a secondary settling tank (SST) and membrane bioreactor (MBR) in parallel. All the antibiotic resistant bacteria and most of the antibiotic resistance genes were present in the raw influent, ranging from 2.5 × 10(2)-3.7 × 10(6) CFU/mL and 1.2× 10(-1)-6.5 × 10(10) GCN/mL, respectively. MBR outperformed the SST system in terms of ARB removal as the ARB targets were largely undetected in MBR effluent, with log removals ranging from 2.7 to 6.8, while SST only had log removals ranging from 0.27 to 4.6. Most of the ARG concentrations were found to have significantly higher in SST effluent than MBR permeate, and MBR had significantly higher removal efficiency for most targets (p < 0.05) except for sul1, sul2, bla(OXA48), intI1 and 16S rRNA genes (p > 0.05). As for the antibiotic residues (AR), there was no significant removal from the start to the end of the treatment process, although MBR had higher removal efficiencies for azithromycin, chloramphenicol, erythromycin, erythromycin-H(2)O, lincomycin, sulfamethoxazole and triclosan, compared to the SST system. In conclusion, MBR outperformed SST in terms of ARB and ARGs removal. However low removal efficiencies of most AR targets were apparent. | 2024 | 38492595 |
| 7998 | 15 | 0.9546 | Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms. The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p < 0.01), and both tetG and ereA increased after wastewater treatment. This may pose a great threat to public health. | 2017 | 26715413 |
| 8008 | 16 | 0.9546 | Reductions of bacterial antibiotic resistance through five biological treatment processes treated municipal wastewater. Wastewater treatment plants are hot spots for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, limited studies have been conducted to compare the reductions of ARB and ARGs by various biological treatment processes. The study explored the reductions of heterotrophic bacteria resistant to six groups of antibiotics (vancomycin, gentamicin, erythromycin, cephalexin, tetracycline, and sulfadiazine) and corresponding resistance genes (vanA, aacC1, ereA, ampC, tetA, and sulI) by five bench-scale biological reactors. Results demonstrated that membrane bioreactor (MBR) and sequencing batch reactor (SBR) significantly reduced ARB abundances in the ranges of 2.80∼3.54 log and 2.70∼3.13 log, respectively, followed by activated sludge (AS). Biological filter (BF) and anaerobic (upflow anaerobic sludge blanket, UASB) techniques led to relatively low reductions. In contrast, ARGs were not equally reduced as ARB. AS and SBR also showed significant potentials on ARGs reduction, whilst MBR and UASB could not reduce ARGs effectively. Redundancy analysis implied that the purification of wastewater quality parameters (COD, NH4 (+)-N, and turbidity) performed a positive correlation to ARB and ARGs reductions. | 2016 | 27384166 |
| 7803 | 17 | 0.9546 | Antibiotic resistances from slaughterhouse effluents and enhanced antimicrobial blue light technology for wastewater decontamionation. The frequencies of 6 different facultative pathogenic bacteria of the ESKAPE group (priority list WHO) and a total of 14 antibiotic resistance genes (ARGs) with different priorities for human medicine were quantified in wastewaters of poultry and pig slaughterhouses using molecular biological approaches. Raw sewage from poultry and pig slaughterhouses was found to be contaminated not only with facultative pathogenic bacteria but also with various categories of clinically relevant ARGs, including ARGs against the reserve antibiotics group. The concentration of the different gene targets decreased after on-site conventional biological or advanced oxidative wastewater treatments, but was not eliminated. Hence, the antimicrobial BlueLight (aBL) in combination with a porphyrin photo-sensitizer was studied with ESKAPE bacteria and real slaughterhouse wastewaters. The applied broad LED-based blue light (420-480 nm) resulted in groups of sensitive, intermediate, and non-sensitive ESKAPE bacteria. The killing effect of aBL was increased in the non-sensitive bacteria Klebsiella pneumoniae and Enterococcus faecium due to the addition of porphyrins in concentrations of 10(-6) M. Diluted slaughterhouse raw wastewater was treated with broad spectrum aBL and in combination with porphyrin. Here, the presence of the photo-sensitizer enhanced the aBL biocidal impact. | 2023 | 37924165 |
| 8046 | 18 | 0.9545 | Responses of aerobic granular sludge to fluoroquinolones: Microbial community variations, and antibiotic resistance genes. In this study, aerobic granular sludge (AGS) was operated under high levels of ammonium for removing three fluoroquinolones (FQs), i.e., ciprofloxacin (CFX), ofloxacin (OFX), and norfloxacin (NFX) at 3, 300, and 900 µg/L, respectively. Two key objectives were to investigate the differential distribution of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in sludge fractions and to evaluate correlations between ARGs and MGEs to nitrifying and denitrifying bacteria. AGS showed excellent stability under the exposure of FQs, with nitrite-oxidizing bacteria (NOB) more sensitive to FQs than ammonium-oxidizing bacteria (AOB). Specific oxygen utilization rates (SOUR) showed a reduction of 26.9% for NOB but only 4.0% of the reduced activity of AOB by 3 μg/L FQs. AGS performed better removal efficiencies for CFX and NFX than OFX, and the efficiencies increased with their elevated concentrations, except at 900 μg/L FQs. The elevated FQ concentrations led to a significant enrichment of intI1 and genus Thauera, while qnrD and qnrS showed no accumulation. Compared to nitrifiers, FQs relevant ARGs and the intI1 gene preferred to exist in denitrifiers, and the abundance of denitrifiers behaved a decreasing trend with the sludge size. Two quinoline-degrading bacteria were found in the AGS system, i.e., Alicycliphilus and Brevundimonas, possibly carrying qnrS and qnrD, respectively. Their relative abundance increased with the sludge size, which was 2.18% in sludge <0.5 mm and increased to 3.70% in sludge >2.0 mm, suggesting that the AGS may be a good choice in treating FQs-containing wastewater. | 2021 | 33676249 |
| 7270 | 19 | 0.9545 | Dynamics of Genotypic and Phenotypic Antibiotic Resistance in a Conventional Wastewater Treatment Plant in 2 Years. Wastewater treatment plants (WWTPs) are considered a sink and a source of antibiotic resistance. In this study, we applied both culture-dependent and SmartChip-based culture-independent approaches for the investigation of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) at Jungnang (JN), located in the Han River, Seoul, South Korea, for 2 years, i.e., 2017 and 2018. The JN WWTP reduced the diversity and abundance of ARB and ARGs but was not sufficient for removing them all. Interestingly, through the treatment process in the JN WWTP, the composition of diverse multidrug-resistant (MDR) bacteria was concentrated mainly into some genera of the Gammaproteobacteria class (Citrobacter, Escherichia-Shigella, and Stenotrophomonas), which could be key carriages to spread ARGs into the environments. In addition, SmartChip analyses showed that the relative abundance and the number of ARGs were significantly decreased from the influents to the effluents in both 2017 and 2018. SmartChip analyses for 2 years also allowed to notify the core ARGs in the influents and the effluents with the presence of clinically relevant core ARGs, such as vanC, bla (OXA) , and bla (NDM) , which persisted in the treatment process. Considering diverse bacterial mechanisms for exchanging and transferring ARGs, the occurrence of MDR bacteria and core ARGs could be a source for the blooming of the antibiotic resistome in the WWTP and nearby environments. | 2022 | 36033841 |