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705400.9869Effective removal of antibiotic resistance genes and potential links with archaeal communities during vacuum-type composting and positive-pressure composting. As a major reservoir of antibiotics, animal manure contributes a lot to the augmented environmental pressure of antibiotic resistance genes (ARGs). This might be the first study to explore the effects of different ventilation types on the control of ARGs and to identify the relationships between archaeal communities and ARGs during the composting of dairy manure. Several ARGs were quantified via Real-time qPCR and microbial communities including bacteria and archaea were analyzed by High-throughput sequencing during vacuum-type composting (VTC) and positive-pressure composting (PPC). The total detected ARGs and class I integrase gene (intI1) under VTC were significantly lower than that under PPC during each stage of the composting (p<0.001). The relative abundance of potential human pathogenic bacteria (HPB) which were identified based on sequencing information and correlation analysis decreased by 74.6% and 91.4% at the end of PPC and VTC, respectively. The composition of archaeal communities indicated that methane-producing archaea including Methanobrevibacter, Methanocorpusculum and Methanosphaera were dominant throughout the composting. Redundancy analysis suggested that Methanobrevibacter and Methanocorpusculum were positively correlated with all of the detected ARGs. Network analysis determined that the possible hosts of ARGs were different under VTC and PPC, and provided new sights about potential links between archaea and ARGs. Our results showed better performance of VTC in reducing ARGs and potential HPB and demonstrated that some archaea could also be influential hosts of ARGs, and caution the risks of archaea carrying ARGs.202031892399
774210.9865The dissimilarity of antibiotic and quorum sensing inhibitor on activated sludge nitrification system: Microbial communities and antibiotic resistance genes. Effects of antibiotics (azithromycin, AZM, 1-40 mg/L) and quorum sensing inhibitor (QSI, 2(5H)-furanone, 1-40 mg/L) combined pollution with environmental concentration of copper on bacterial/archaeal community and antibiotic resistance genes (ARGs) in activated sludge system were explored. QSI inhibited nitrification more obviously than AZM. AZM and QSI were synergistic inhibitions on bacterial diversity, and AZM inhibited bacterial compositions more than QSI. While, QSI had more impacts on archaeal diversity/compositions. Less interactions among bacteria and archaea communities with Aquimonas as keystone genus. Functional differences in bacteria/archaea communities were little, and AZM had more effects on metabolism. AZM mainly affected nitrifying bacteria (Candidatus Nitrospira nitrificans and Nitrosomonas). Specific denitrifying bacteria were enriched by AZM (Brevundimonas, 1.76-31.69%) and QSI (Comamonas, 0.61-9.61%), respectively. AZM enriched ARGs more easily than QSI and they were antagonistic to proliferation of ARGs. Bacteria were main hosts of ARGs (macrolide-lincosamide-streptogramin B, other/efflux, etc.) and archaea (Methanosphaerula, Methanolobus) carried multiple ARGs.202235306131
349720.9865Biomarkers of antibiotic resistance genes during seasonal changes in wastewater treatment systems. To evaluate the seasonal distribution of antibiotic resistance genes (ARGs) and explore the reason for their patterns in different seasons and different systems, two wastewater treatment systems were selected and analyzed using high-throughput qPCR. Linear discriminant analysis (LDA) effect size (LEfSe) was used to discover the differential ARGs (biomarkers) and estimate the biomarkers' effect size. We found that the total absolute abundances of ARGs in inflows and excess sludge samples had no obvious seasonal fluctuations, while those in winter outflow samples decreased in comparison with the inflow samples. Eleven differentially abundant ARGs (biomarker genes, BmGs) (aadA5-02, aac-6-II, cmlA1-01, cmlA1-02, blaOXA10-02, aadA-02, tetX, aadA1, ereA, qacEΔ1-01, and blaTEM) in summer samples and 10 BmGs (tet-32, tetA-02, aacC2, vanC-03, aac-6-I1, tetE, ermB, mefA, tnpA - 07, and sul2) in winter samples were validated. According to 16S rRNA gene sequencing, the relative abundance of bacteria at the phylum level exhibited significant seasonal changes in outflow water (OW), and biomarker bacteria (BmB) were discovered at the family (or genus) level. Synechococcus and vadinCA02 are BmB in summer, and Trichococcus, Lactococcus, Pelosinus, Janthinobacterium, Nitrosomonadaceae and Sterolibacterium are BmB in winter. In addition, BmB have good correlations with BmGs in the same season, which indicates that bacterial community changes drive different distributions of ARGs during seasonal changes and that LEfSe is an acute and effective method for finding significantly different ARGs and bacteria between two or more classes. In conclusion, this study demonstrated the seasonal changes of BmGs and BmB at two wastewater treatment systems.201829169020
773330.9865A glance at the gut microbiota and the functional roles of the microbes based on marmot fecal samples. Research on the gut microbiota, which involves a large and complex microbial community, is an important part of infectious disease control. In China, few studies have been reported on the diversity of the gut microbiota of wild marmots. To obtain full details of the gut microbiota, including bacteria, fungi, viruses and archaea, in wild marmots, we have sequenced metagenomes from five sample-sites feces on the Hulun Buir Grassland in Inner Mongolia, China. We have created a comprehensive database of bacterial, fungal, viral, and archaeal genomes and aligned metagenomic sequences (determined based on marmot fecal samples) against the database. We delineated the detailed and distinct gut microbiota structures of marmots. A total of 5,891 bacteria, 233 viruses, 236 fungi, and 217 archaea were found. The dominant bacterial phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinomycetes. The viral families were Myoviridae, Siphoviridae, Phycodnaviridae, Herpesviridae and Podoviridae. The dominant fungi phyla were Ascomycota, Basidiomycota, and Blastocladiomycota. The dominant archaea were Biobacteria, Omoarchaea, Nanoarchaea, and Microbacteria. Furthermore, the gut microbiota was affected by host species and environment, and environment was the most important factor. There were 36,989 glycoside hydrolase genes in the microbiota, with 365 genes homologous to genes encoding β-glucosidase, cellulase, and cellulose β-1,4-cellobiosidase. Additionally, antibiotic resistance genes such as macB, bcrA, and msbA were abundant. To sum up, the gut microbiota of marmot had population diversity and functional diversity, which provides a basis for further research on the regulatory effects of the gut microbiota on the host. In addition, metagenomics revealed that the gut microbiota of marmots can degrade cellulose and hemicellulose.202337125200
716740.9864Occurrence and distribution of antibiotic pollution and antibiotic resistance genes in seagrass meadow sediments based on metagenomics. Seagrass meadows are one of the most important coastal ecosystems that provide essential ecological and economic services. The contamination levels of antibiotic and antibiotic resistance genes (ARGs) in coastal ecosystems are severely elevated owing to anthropogenic disturbances, such as terrestrial input, aquaculture effluent, and sewage discharge. However, few studies have focused on the occurrence and distribution of antibiotics and their corresponding ARGs in this habitat. Thus, we investigated the antibiotic and ARGs profiles, microbial communities, and ARG-carrying host bacteria in typical seagrass meadow sediments collected from Swan Lake, Caofeidian shoal harbor, Qingdao Bay, and Sishili Bay in the Bohai Sea and northern Yellow Sea. The total concentrations of 30 detected antibiotics ranged from 99.35 to 478.02 μg/kg, tetracyclines were more prevalent than other antibiotics. Metagenomic analyses showed that 342 ARG subtypes associated with 22 ARG types were identified in the seagrass meadow sediments. Multidrug resistance genes and RanA were the most dominant ARG types and subtypes, respectively. Co-occurrence network analysis revealed that Halioglobus, Zeaxanthinibacter, and Aureitalea may be potential hosts at the genus level, and the relative abundances of these bacteria were higher in Sishili Bay than those in other areas. This study provided important insights into the pollution status of antibiotics and ARGs in typical seagrass meadow sediments. Effective management should be performed to control the potential ecological health risks in seagrass meadow ecosystems.202438782270
699150.9862Distribution and drivers of antibiotic resistance genes in brackish water aquaculture sediment. Brackish water aquaculture has brought numerous economic benefits, whereas anthropogenic activities in aquaculture may cause the dissemination of antibiotic resistance genes (ARGs) in brackish water sediments. The intricate relationships between environmental factors and microbial communities as well as their role in ARGs dissemination in brackish water aquaculture remain unclear. This study applied PCR and 16S sequencing to identify the variations in ARGs, class 1 integron gene (intI1) and microbial communities in brackish water aquaculture sediment. The distribution of ARGs in brackish water aquaculture sediment was similar to that in freshwater aquaculture, and the sulfonamide resistance gene sul1 was the indicator of ARGs. Proteobacteria and Firmicutes were the dominant phyla, and Paenisporosarcina (p_ Firmicutes) was the dominant genus. The results of correlation, network and redundancy analysis indicated that the microbial community in the brackish water aquaculture sediment was function-driven. The neutral model and variation partitioning analysis were used to verify the ecological processes of the bacterial community. The normalized stochasticity ratio showed that pond bacteria community was dominated by determinacy, which was affected by aquaculture activities. The total nitrogen and organic matter influenced the abundance of ARGs, while Proteobacteria and Thiobacillus (p_Proteobacteria) were the key antibiotic-resistant hosts. Our study provides insight into the prevalence of ARGs in brackish water aquaculture sediments, and indicates that brackish water aquaculture is a reservoir of ARGs.202336436623
766660.9862Antibiotic resistance genes allied to the pelagic sediment microbiome in the Gulf of Khambhat and Arabian Sea. Antibiotics have been widely spread in the environments, imposing profound stress on the resistome of the residing microbes. Marine microbiomes are well established large reservoirs of novel antibiotics and corresponding resistance genes. The Gulf of Khambhat is known for its extreme tides and complex sedimentation process. We performed high throughput sequencing and applied bioinformatics techniques on pelagic sediment microbiome across four coordinates of the Gulf of Khambhat to assess the marine resistome, its corresponding bacterial community and compared with the open Arabian Sea sample. We identified a total of 2354 unique types of resistance genes, with most abundant and diverse gene profile in the area that had anthropogenic activities being carried out on-shore. The genes with >1% abundance in all samples included carA, macB, sav1866, tlrC, srmB, taeA, tetA, oleC and bcrA which belonged to the macrolides, glycopeptides and peptide drug classes. ARG enriched phyla distribution was quite varying between all the sites, with Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes among the dominant phyla. Based on the outcomes, we also propose potential biomarker candidates Desulfovibrio, Thermotaga and Pelobacter for antibiotic monitoring in the two of the Gulf samples probable contamination prone environments, and genera Nitrosocccus, Marinobacter and Streptomyces in the rest of the three studied samples. Outcomes support the concept that ARGs naturally originate in environments and human activities contribute to the dissemination of antibiotic resistance.201930412889
794870.9861Ciprofloxacin increased abundance of antibiotic resistance genes and shaped microbial community in epiphytic biofilm on Vallisneria spiralis in mesocosmic wetland. This study investigated the fate of ciprofloxacin (CIP) in wetlands dominated by Vallisneria spiralis. About 99% of CIP was degraded from overlaying water within 4 days of treatment but significantly inhibited the nutrient removal capacity (TN, TP, and COD) by causing a drastic reduction in microbial aggregation in epiphytic biofilm and bacterial biodiversity. CIP triggered resistance mechanisms among dominant bacteria phyla such as Proteobacteria, Actinobacteria, and Planctomycetes causing their increased relative abundance. Additionally, the relative abundances of eukaryotic microorganisms (including; Chloroplastida, Metazoa, and Rhizaria) and 13 ARGs subtypes (including; Efflux pump, Tetracycline, Multi-drug, Rifampin, Beta-lactam, Peptide, Trimethoprim) were significantly increased. While dominant metabolic pathways such as Carbohydrate, amino acid, energy and nucleotide metabolism were inhibited. This study revealed that V. spiralis has great sorption capacity for CIP than sediment and though CIP was effectively removed from the overlying water, it caused a prolonged effect on the epiphytic biofilm microbial communities.202133412499
700980.9861Antibiotic resistance genes and bacterial communities in cornfield and pasture soils receiving swine and dairy manures. Land application of animal manure could change the profiles of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs) and bacterial communities in receiving soils. Using high-throughput real-time quantitative PCR and 16S rRNA amplicon sequencing techniques, this study investigated the ARGs and bacterial communities in field soils under various crop (corn and pasture) and manure (swine and dairy) managements, which were compared with those of two non-manured reference soils from adjacent golf course and grassland. In total 89 unique ARG subtypes were found in the soil samples and they conferred resistance via efflux pump, cellular protection and antibiotic deactivation. Compared to the ARGs in the golf course and grassland soils (28 and 34 subtypes respectively), manured soils generally had greater ARG diversity (36-55 subtypes). Cornfield soil frequently receiving raw swine manure had the greatest ARG abundance. The short-term (one week) application of composted and liquid swine manures increased the diversity and total abundance of ARGs in cornfield soils. Intriguingly the composted swine manure only marginally increased the total abundance of ARGs, but substantially increased the number of ARG subtypes in the cornfield soils. The network analysis revealed three major network modules in the co-occurrence patterns of ARG subtypes, and the hubs of these major modules (intl1-1, vanC, and pncA) may be candidates for selecting indicator genes for surveillance of ARGs in manured soils. The network analyses between ARGs and bacteria taxa revealed the potential host bacteria for the detected ARGs (e.g., aminoglycoside resistance gene aacC4 may be mainly carried by Acidobacteriaceae). Overall, this study highlighted the potentially varying impact of various manure management on antibiotic resistome and microbiome in cornfield and pasture soils.201930861417
766790.9860Metagenomics uncovers microbiome and resistome in soil and reindeer faeces from Ny-Ålesund (Svalbard, High Arctic). Research on the microbiome and resistome in polar environments, such as the Arctic, is crucial for understanding the emergence and spread of antibiotic resistance genes (ARGs) in the environment. In this study, soil and reindeer faeces samples collected from Ny-Ålesund (Svalbard, High Arctic) were examined to analyze the microbiome, ARGs, and biocide/metal resistance genes (BMRGs). The dominant phyla in both soil and faeces were Pseudomonadota, Actinomycetota, and Bacteroidota. A total of 2618 predicted Open Reading Frames (ORFs) containing antibiotic resistance genes (ARGs) were detected. These ARGs belong to 162 different genes across 17 antibiotic classes, with rifamycin and multidrug resistance genes being the most prevalent. We focused on investigating antibiotic resistance mechanisms in the Ny-Ålesund environment by analyzing the resistance genes and their biological pathways. Procrustes analysis demonstrated a significant correlation between bacterial communities and ARG/BMRG profiles in soil and faeces samples. Correlation analysis revealed that Pseudomonadota contributed most to multidrug and triclosan resistance, while Actinomycetota were predominant contributors to rifamycin and aminoglycoside resistance. The geochemical factors, SiO(4)(2-) and NH(4)(+), were found to significantly influence the microbial composition and ARG distribution in the soil samples. Analysis of ARGs, BMRGs, virulence factors (VFs), and pathogens identified potential health risks associated with certain bacteria, such as Cryobacterium and Pseudomonas, due to the presence of different genetic elements. This study provided valuable insights into the molecular mechanisms and geochemical factors contributing to antibiotic resistance and enhanced our understanding of the evolution of antibiotic resistance genes in the environment.202439159777
6907100.9860Deciphering the impact of organic loading rate and digestate recirculation on the occurrence patterns of antibiotics and antibiotic resistance genes in dry anaerobic digestion of kitchen waste. Organic loading rate (OLR) is crucial for determining the stability of dry anaerobic digestion (AD). Digestate recirculation contributes to reactor stability and enhances methane production. Nevertheless, the understanding of how OLR and digestate recirculation affect the abundance and diversity of antibiotics and antibiotic resistance genes (ARGs), as well as the mechanisms involved in the dissemination of ARGs, remains limited. This study thoroughly investigated this critical issue through a long-term pilot-scale experiment. The metabolome analyses revealed the enrichment of various antibiotics, such as aminoglycoside, tetracycline, and macrolide, under low OLR conditions (OLR ≤ 4.0 g·VS/L·d) and the reactor instability. Antibiotics abundance decreased by approximately 19.66-31.69 % during high OLR operation (OLR ≥ 6.0 g·VS/L·d) with digestate recirculation. The metagenome analyses demonstrated that although low OLR promoted reactor stability, it facilitated the proliferation of antibiotic-resistant bacteria, such as Pseudomonas, and triggered functional profiles related to ATP generation, oxidative stress response, EPS secretion, and cell membrane permeability, thereby facilitating horizontal gene transfer (HGT) of ARGs. However, under stable operation at an OLR of 6.0 g·VS/L·d, there was a decrease in ARGs abundance but a notable increase in human pathogenic bacteria (HPB) and mobile genetic elements (MGEs). Subsequently, during reactor instability, the abundance of ARGs and HPB increased. Notably, during digestate recirculation at OLR levels of 6.0 and 7.0 g·VS/L·d, the process attenuated the risk of ARGs spread by reducing the diversity of ARGs hosts, minimizing interactions among ARGs hosts, ARGs, and MGEs, and weakening functional profiles associated with HGT of ARGs. Overall, digestate recirculation aids in reducing the abundance of antibiotics and ARGs under high OLR conditions. These findings provide advanced insights into how OLR and digestate recirculation affect the occurrence patterns of antibiotics and ARGs in dry AD.202438968733
3501110.9860Microbial community and antibiotic resistance gene distribution in food waste, anaerobic digestate, and paddy soil. The study assessed the occurrence and distribution of microbial community and antibiotic resistance genes (ARGs) in food waste, anaerobic digestate, and paddy soil samples, and revealed the potential hosts of ARGs and factors influencing their distribution. A total of 24 bacterial phyla were identified, of which 16 were shared by all samples, with Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria accounting for 65.9-92.3 % of the total bacterial community. Firmicutes was the most abundant bacteria in food waste and digestate samples, accounting for 33-83 % of the total microbial community. However, in paddy soil samples with digestate, Proteobacteria had the highest relative abundance of 38-60 %. Further, 22 ARGs were detected in food waste and digestate samples, with multidrug, macrolide-lincosamide-streptogramin (MLS), bacitracin, aminoglycoside, tetracycline, vancomycin, sulfonamide, and rifamycin resistance genes being the most abundant and shared by all samples. The highest total relative abundance of ARGs in food waste, digestate, and soil without and with digestate was detected in samples from January 2020, May 2020, October 2019, and May 2020, respectively. The MLS, vancomycin, tetracycline, aminoglycoside, and sulfonamide resistance genes had higher relative abundance in food waste and anaerobic digestate samples, whereas multidrug, bacteriocin, quinolone, and rifampin resistance genes were more abundant in paddy soil samples. Redundancy analysis demonstrated that aminoglycoside, tetracycline, sulfonamide, and rifamycin resistance genes were positively correlated with total ammonia nitrogen and pH of food waste and digestate samples. Vancomycin, multidrug, bacitracin, and fosmidomycin resistance genes had positive correlations with potassium, moisture, and organic matter in soil samples. The co-occurrence of ARG subtypes with bacterial genera was investigated using network analysis. Actinobacteria, Proteobacteria, Bacteroidetes, and Acidobacteria were identified as potential hosts of multidrug resistance genes.202337196953
3482120.9859Metagenomic profiling of ARGs in airborne particulate matters during a severe smog event. Information is currently limited regarding the distribution of antibiotic resistance genes (ARGs) in smog and their correlations with airborne bacteria. This study characterized the diversity and abundance of ARGs in the particulate matters (PMs) of severe smog based on publicly available metagenomic data, and revealed the occurrence of 205 airborne ARG subtypes, including 31 dominant ones encoding resistance to 11 antibiotic types. Among the detectable ARGs, tetracycline, β-lactam and aminoglycoside resistance genes had the highest abundance, and smog and soil had similar composition characteristics of ARGs. During the smog event, the total abundance of airborne ARGs ranged from 4.90 to 38.07ppm in PM(2.5) samples, and from 7.61 to 38.49ppm in PM(10) samples, which were 1.6-7.7 times and 2.1-5.1 times of those in the non-smog day, respectively. The airborne ARGs showed complicated co-occurrence patterns, which were heavily influenced by the interaction of bacterial community, and physicochemical and meteorological factors. Lactobacillus and sulfonamide resistance gene sul1 were determined as keystones in the co-occurrence network of microbial taxa and airborne ARGs. The results may help to understand the distribution patterns of ARGs in smog for the potential health risk evaluation.201829751438
6990130.9859Metagenomics 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.202336075417
7735140.9859Metagenomics insights into microbiome and antibiotic resistance genes from free living amoeba in chlorinated wastewater effluents. Free living amoeba (FLA) are among the organisms commonly found in wastewater and are well-established hosts for diverse microbial communities. Despite its clinical significance, there is little knowledge on the FLA microbiome and resistome, with previous studies relying mostly on conventional approaches. In this study we comprehensively analyzed the microbiome, antibiotic resistome and virulence factors (VFs) within FLA isolated from final treated effluents of two wastewater treatment plants (WWTPs) using shotgun metagenomics. Acanthamoeba has been identified as the most common FLA, followed by Entamoeba. The bacterial diversity showed no significant difference (p > 0.05) in FLA microbiomes obtained from the two WWTPs. At phylum level, the most dominant taxa were Proteobacteria, followed by Firmicutes and Actinobacteria. The most abundant genera identified were Enterobacter followed by Citrobacter, Paenibacillus, and Cupriavidus. The latter three genera are reported here for the first time in Acanthamoeba. In total, we identified 43 types of ARG conferring resistance to cephalosporins, phenicol, streptomycin, trimethoprim, quinolones, cephalosporins, tigecycline, rifamycin, and kanamycin. Similarly, a variety of VFs in FLA metagenomes were detected which included flagellar proteins, Type IV pili twitching motility proteins (pilH and rpoN), alginate biosynthesis genes AlgI, AlgG, AlgD and AlgW and Type VI secretion system proteins and general secretion pathway proteins (tssM, tssA, tssL, tssK, tssJ, fha, tssG, tssF, tssC and tssB, gspC, gspE, gspD, gspF, gspG, gspH, gspI, gspJ, gspK, and gspM). To the best of our knowledge, this is the first study of its kind to examine both the microbiomes and resistome in FLA, as well as their potential pathogenicity in treated effluents. Additionally, this study showed that FLA can host a variety of potentially pathogenic bacteria including Paenibacillus, and Cupriavidus that had not previously been reported, indicating that their relationship may play a role in the spread and persistence of antibiotic resistant bacteria (ARBs) and antibiotic resistance genes (ARGs) as well as the evolution of novel pathogens.202438471337
8017150.9859Dose-Dependent Effect of Tilmicosin Residues on ermA Rebound Mediated by IntI1 in Pig Manure Compost. The impact of varying antibiotic residue levels on antibiotic resistance gene (ARG) removal during composting is still unclear. This study investigated the impact of different residue levels of tilmicosin (TIM), a common veterinary macrolide antibiotic, on ARG removal during pig manure composting. Three groups were used: the CK group (no TIM), the L group (246.49 ± 22.83 mg/kg TIM), and the H group (529.99 ± 16.15 mg/kg TIM). Composting removed most targeted macrolide resistance genes (MRGs) like ereA, ermC, and ermF (>90% removal), and reduced ermB, ermX, ermQ, acrA, acrB, and mefA (30-70% removal). However, ermA increased in abundance. TIM altered compost community structure, driving succession through a deterministic process. At low doses, TIM reduced MRG-bacteria co-occurrence, with horizontal gene transfer via intI1 being the main cause of ermA rebound. In conclusion, composting reduces many MRG levels in pig manure, but the persistence and rebound of genes like ermA reveal the complex interactions between composting conditions and microbial gene transfer.202541011454
8027160.9859Behavior of tetracycline and sulfamethoxazole and their corresponding resistance genes in three-dimensional biofilm-electrode reactors with low current. Antibiotics and antibiotic resistance genes (ARGs) have become major health concerns. In this study, three-dimensional biofilm-electrode reactors (3D-BERs) under low current were designed to assess their performance in removing tetracycline (TC) and sulfamethoxazole (SMX) from synthetic wastewater. In addition, the fates of the corresponding ARGs in microbial communities were investigated. The mass removal ratios of TC and SMX by the 3D-BERs were 82.6-97.3% and 72.2-93.2%, respectively. There were obvious increases in the relative abundances of all target genes after ∼2 months. The tet and sul genes were significantly upregulated by high concentrations of antibiotics in the cathode layer, and higher ARG levels were evident in the cathodes than in the anodes. High-throughput sequencing identified Methylotenera, Candidatus Accumulibacter, Limnohabitans, Dechloromonas, Crenothrix, and Caldilinea as the dominant genera in the samples at the end of the experiment, after ∼8 months, and these bacteria potentially exhibited antibiotic resistance. The relative abundances and compositions of the dominant microbial populations changed throughout the course of antibiotic removal in the 3D-BERs.201727925498
7263170.9858A comprehensive insight into tetracycline resistant bacteria and antibiotic resistance genes in activated sludge using next-generation sequencing. In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB) and antibiotic resistance genes (ARGs) in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera consisting of Sulfuritalea, Armatimonas, Prosthecobacter, Hyphomicrobium, Azonexus, Longilinea, Paracoccus, Novosphingobium and Rhodobacter were identified as potential TRB in the sludge. Results of qPCR, molecular cloning and metagenomic analysis consistently indicated that tetracycline treatment could increase both the abundance and diversity of the tet genes, but decreased the occurrence and diversity of non-tetracycline ARG, especially sulfonamide resistance gene sul2. Cluster analysis showed that tetracycline treatment at subinhibitory concentrations (5 mg/L) was found to pose greater effects on the bacterial community composition, which may be responsible for the variations of the ARGs abundance. This study indicated that joint use of 454 pyrosequencing and Illumina high-throughput sequencing can be effectively used to explore ARB and ARGs in the environment, and future studies should include an in-depth investigation of the relationship between microbial community, ARGs and antibiotics in sewage treatment plant (STP) sludge.201424905407
7995180.9858Risk of penicillin fermentation dreg: Increase of antibiotic resistance genes after soil discharge. Penicillin fermentation dreg (PFD) is a solid waste discharged by pharmaceutical enterprises in the fermentation production process. Due to the residual antibiotic of PFD, the risk of antibiotic resistance bacteria (ARB) generation should be considered in the disposal process. High-throughput quantitative PCR (HT-qPCR) and 16S rRNA gene sequencing were performed to investigate the effect of PFD on the dynamics of antibiotic resistance genes (ARGs) and bacterial community during a lab-scale soil experiment. After the application of PFD, the bacterial number and diversity showed an obvious decrease in the initial days. The abundances of Streptomyces and Bacillus, which are the most widespread predicted source phyla of ARGs, increased remarkably from 4.42% to 2.59%-22.97% and 21.35%. The increase of ARGs was observed during the PFD application and the ARGs carried by PFD itself contributed to the initiation of soil ARGs. The results of redundancy analysis (RDA) show that the shift in bacterial community induced by variation of penicillin content is the primary driver shaping ARGs compositions.202032023801
8104190.9858Comparative network analysis revealing the mechanisms of antibiotic resistance genes removal by leachate recirculation under different hydraulic loadings. The wide dissemination of antibiotic resistance is a pervasive global health threat, and landfill leachate has been an important hotspot of antibiotic resistance genes (ARGs). This study aimed to investigate the removal performance and mechanism of ARGs from leachate under different hydraulic loadings. ARGs removal efficiencies were dependent on hydraulic loadings and ARGs types other than operating time, and reactors operated with hydraulic loadings of 25 and 50 L·m(-3)·d(-1) exhibited greater removal potential than 100 L·m(-3)·d(-1). ARGs removal patterns varied from different subtypes, for genes sul2, tetQ, aadA1 and bla(CTX-M) were eliminated from both leachate and refuse, and tetM, ermB, mefA, and strB were removed from leachate but enriched in refuse. Under different hydraulic loadings, bacterial communities shift shaped ARGs fates in leachate, but refuse had more stable antibiotic resistome and community structure. The topology comparison analysis of co-occurrence network suggested a closer hosting relationship between ARGs and genera in refuse than leachate. Furthermore, taxonomic category of host bacteria other than diversity of host genera determined the ARGs removal, and the ARGs harbored in phyla Cyanobacteria, Tenericutes and Acidobacteria were more likely to be removed. These findings can potentially foster the understanding of ARGs removal mechanism in biological treatment processes under different operating conditions.201930176445