Mobile genetic elements facilitate the transmission of antibiotic resistance genes in multidrug-resistant Enterobacteriaceae from duck farms

Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety.

Performance Parameters:Demobilization Antibiotic Resistant Bacteria(ARB)and Carrying Genes(ARG)in Wastewater Disinfection

The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.

Trifunctional Cu-Mesh/Cu_(2)O@FeO Nanoarrays for Highly Efficient Degradation of Antibiotic, Inactivation of Antibiotic-Resistant Bacteria, and Damage of Antibiotics Resistance Genes

Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.

UV-Based Advanced Oxidation Processes for Antibiotic Resistance Control: Efficiency, Influencing Factors, and Energy Consumption

Antibiotic resistant bacteria(ARB)with antibiotic resistance genes(ARGs)can reduce or eliminate the effectiveness of antibiotics and thus threaten human health.The United Nations Environment Programme considers antibiotic resistance the first of six emerging issues of concern.Advanced oxidation processes(AOPs)that combine ultraviolet(UV)irradiation and chemical oxidation(primarily chlorine,hydrogen peroxide,and persulfate)have attracted increasing interest as advanced water and wastewater treatment technologies.These integrated technologies have been reported to significantly elevate the efficiencies of ARB inactivation and ARG degradation compared with direct UV irradiation or chemical oxidation alone due to the generation of multiple reactive species.In this study,the performance and underlying mechanisms of UV/chlorine,UV/hydrogen peroxide,and UV/persulfate processes for controlling ARB and ARGs were reviewed based on recent studies.Factors affecting the process-specific efficiency in controlling ARB and ARGs were discussed,including biotic factors,oxidant dose,UV fluence,pH,and water matrix properties.In addition,the cost-effectiveness of the UV-based AOPs was evaluated using the concept of electrical energy per order.The UV/chlorine process exhibited a higher efficiency with lower energy consumption than other UV-based AOPs in the wastewater matrix,indicating its potential for ARB inactivation and ARG degradation in wastewater treatment.Further studies are required to address the trade-off between toxic byproduct formation and the energy efficiency of the UV/chlorine process in real wastewater to facilitate its optimization and application in the control of ARB and ARGs.

Fate and Behavior of Tetracycline Resistance Genes in Activated Carbon Adsorption

The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L-1 was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10-12 - 4.64 × 10-9 and 7.02 × 10-11 - 1.59 × 10-8 copies·mg-1·min-1, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (KF) values were 1.71 × 103 - 8.00 × 109 (copies·g-1)1-1/n for coal-based ACs and 7.00 × 108 - 3.00 × 1010 (copies·g-1)1-1/n for wood-based ones. In addition, the correlation analysis between KF values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.

Dissemination of Resistance Integrons and Genes Coding for Blse and Cabapenemases in the Urban Drainage Network in Cote d’Ivoire

Antibiotic resistance has become a major threat to human health worldwide. Environment, particularly the water environment, has long been overlooked as a player in the antibiotic resistance cycle, although its role remains unclear. These can provide an ideal setting for the acquisition and dissemination of antibiotic resistance, as they are frequently affected by anthropogenic activities. The objective of this study was to establish a diffusion map of resistance integrons used as genetic markers of resistance associated with antibiotic resistance conferring genes (ARGs). Total DNA extracts from non-cultivable bacterial communities were used for the analyses. These communities were obtained from wastewater samples from 14 sites upstream and downstream of drainage channels or effluents in the cities of Abidjan, Bouaké, and Yamoussoukro. The results obtained correspond to the number of positives among the treated samples (n = 39). Among the genetic markers of dissemination, class 1 integrons were the most evident in 94.8% of samples in Abidjan (93.3%), Bouaké (100%) and Yamoussoukro (91.6%). Class 2 integrons and class 3 integrons were found respectively in 41% and 51% of all samples. Genes coding for β-lactamases and blaTEM was identified in almost all samples at a rate of 97.4%. A co-presence of the three genes blaTEM, blaSHV and blaCTX-M is also remarkable in the sites of the city of Yamoussoukro. Among the genes coding for carbapenemases, only blaKPC 17.94%, blaNDM 30.76% and blaOXA48 38.46% were detected in the samples.

The Role of Wastewater Treatment Plants in the Environmental Dissemination of Antibiotic Resistant Bacteria (ARB) and Resistance Genes (ARG)

This study was conducted to evaluate the influence of wastewater treatment processes on the prevalence of antibiotic resistance fecal coliform (FC) and antibiotic resistance genes (ARGs) of FC. In addition, the occurrence of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in surface waters receiving wastewater was evaluated. Greater resistance against penicillin (P), colisitin (CT) and ampicillin (AMP) were observed for FC isolated from effluent disinfected by chlorine (71%), than that disinfected by UV (45%). The greatest resistance against six antibiotics was recorded for FC isolates from effluent disinfected by chlorine. The prevalence of tetB and blaSHV was lowest in isolates from chlorine-disinfected effluents. The occurrence of ARG blaSHV was highest in FC isolated from effluent disinfected by UV. A significant correlation was recorded between FC levels in surface waters and the level of bacterial resistance to ampicillin (P SHV in effluents and in surface waters. TetA and tetC were highly prevalent in surface water compared to tetB. The results of the study demonstrate the widespread prevalence of ARB and ARG in wastewater and receiving water bodies. The result indicates that the source of ARB and ARG in surface waters originate from wastewater. Released ARB and ARG may serve as the source of ARG to pathogenic bacteria in surface waters. Disinfection processes may influence the selection of antibiotic resistant patterns of bacteria.

Antibiotic resistance analysis and coping strategies of helicobacter pylori

Helicobacter pylori(H.pylori)is a Gram-negative bacterium that mainly colonizes the stomach and duodenum,and it can cause gastrointestinal diseases such as gastric inflammation,peptic ulcer and gastric cancer,and eradication of H.pylori can effectively stop the occurrence and development of gastrointestinal diseases.Antibiotics are one of the main drugs used to treat H.pylori.Due to the long-term application of antibiotics,the resistance rate of H.pylori to antibiotics increases year by year,which greatly reduces the eradication rate of H.pylori and increases the difficulty of re-treatment and the economic burden of patients.In this paper,we will review three aspects of H.pylori resistance status,resistance mechanism and treatment to provide reference for the progress of H.pylori resistance research and its treatment strategy.

Genetic Diversity,Antibiotic Resistance,and Pathogenicity of Aeromonas Species from Food Products in Shanghai,China

Objective Aeromonas has recently been recognized as an emerging human pathogen.Aeromonasassociated diarrhea is a phenomenon occurring worldwide.This study was designed to determine the prevalence,genetic diversity,antibiotic resistance,and pathogenicity of Aeromonas strains isolated from food products in Shanghai.Methods Aeromonas isolates(n=79)collected from food samples were analyzed using concatenated gyrB-cpn60 sequencing.The antibiotic resistance of these isolates was determined using antimicrobial susceptibility testing.Pathogenicity was assessed usingβ-hemolytic,extracellular protease,virulence gene detection,C.elegans liquid toxicity(LT),and cytotoxicity assays.Results Eight different species were identified among the 79 isolates.The most prevalent Aeromonas species were A.veronii[62(78.5%)],A.caviae[6(7.6%)],A.dhakensis[3(3.8%)],and A.salmonicida[3(3.8%)].The Aeromonas isolates were divided into 73 sequence types(STs),of which 65 were novel.The isolates were hemolytic(45.6%)and protease-positive(81.0%).The most prevalent virulence genes were act(73.4%),fla(69.6%),aexT(36.7%),and ascV(30.4%).The results of C.elegans LT and cytotoxicity assays revealed that A.dhakensis and A.hydrophila were more virulent than A.veronii,A.caviae,and A.bivalvium.Antibiotic resistance genes[tetE,blaTEM,tetA,qnrS,aac(6)-Ib,mcr-1,and mcr-3]were detected in the isolates.The multidrug-resistance rate of the Aeromonas isolates was 11.4%,and 93.7%of the Aeromonas isolates were resistant to cefazolin.Conclusion The taxonomy,antibiotic resistance,and pathogenicity of different Aeromonas species varied.The Aeromonas isolates A.dhakensis and A.hydrophila were highly pathogenic,indicating that food-derived Aeromonas isolates are potential risks for public health and food safety.The monitoring of food quality and safety will result in better prevention and treatment strategies to control diarrhea illnesses in China.

微藻生物系统去除抗生素和ARGs的研究进展

抗生素与抗生素抗性基因(ARGs)污染严重危害人类健康,微藻生物技术在处理抗生素废水过程中表现出良好的效果。文章首先总结了微藻对于不同种类抗生素的去除机理,包括生物吸附、生物累积、生物降解、光生物降解和水解挥发5种。分析了微藻在去除抗生素过程中的重要影响因素,包括pH、水力停留时间、光照、抗生素的种类与浓度和微藻的种类。并总结了微藻对ARGs的去除机制,包括移动基因元件的去除及活性氧自由基的猝灭。最后,文章指出了微藻处理抗生素废水过程中仍然存在的问题,进一步明确了今后微藻生物技术处理抗生素废水的重点研究方向。

Enhanced removal of antibiotic resistance genes during chicken manure composting after combined inoculation of Bacillus subtilis with biochar

This study explored the combined effects of Bacillus subtilis inoculation with biochar on the evolution of bacterial communities,antibiotic resistance genes(ARGs),and mobile genetic elements(MGEs)during the composting of chicken manure.The results showed that B.subtilis inoculation combined with biochar increased bacterial abundance and diversity as well as prolonged the compost thermophilic period.Promoted organic matter biodegradation and facilitated the organic waste compost humification process,reduced the proliferation of ARGs by altering the bacterial composition.Firmicutes and Actinobacteriota were the main resistant bacteria related to ARGs and MGEs.The decrease in ARGs and MGEs was associated with the reduction in the abundance of related host bacteria.Compost inoculation with B.subtilis and the addition of biochar could promote nutrient transformation,reduce the increase in ARGs and MGEs,and increase the abundance of beneficial soil taxa.

Evaluating human exposure to antibiotic resistance genes

Antibiotic resistance is an escalating global concern,leading to millions of annual fatalities.Antibiotic resistance genes(ARGs)present in bacteria equip them to withstand the effects of antibiotics.Intra-and interspecific ARGs transmission through horizontal gene transfer further exacerbates resistance dissemination.The presence of ARGs in the environment heightens the probability of human exposure via direct inhalation,ingestion,or contact with polluted air,food,or water,posing substantial biosafety and health hazards.Consequently,ARGs represent a critical focal point in public health and environmental safety and are classified as emerging contaminants.This perspective underscores the necessity to assess ARG exposure within the One Health framework and to accord greater attention to the mitigation strategies and tactics associated with ARGs.

沈阳典型粳稻种植区稻田土壤ARGs和MGEs污染分布特征分析

农田土壤中抗生素抗性基因(ARGs)与可移动遗传元件(MGEs)的污染问题,在学术界已引发广泛关注。为研究沈阳市粳稻种植区稻田土壤中ARGs与MGEs的存在和相关性,并探讨其对土壤-植物系统的潜在影响,通过采集沈阳市辽中区、新民市、沈北新区和苏家屯区的粳稻种植区域土壤样品,利用高通量qPCR技术,对285个ARGs、10个MG-Es和一个16S rRNA基因进行检测和定量分析。结果表明:在不同地区的稻田土壤中共检测到273种ARGs和MGEs,且种类和丰度存在显著差异。进一步的相关性分析发现,ARGs与MGEs之间存在一定相关性,并且这种相关性在不同地区间有所差异。多种ARGs与MGEs之间存在显著正相关(p<0.05),其中部分ARGs[tet(32)等]与MGEs(tnpA-01等)存在及极显著正相关(p<0.01),这表明在土壤中MGEs对ARGs迁移和扩散起到促进作用。4个采样区根际土中ARGs和MGEs的总相对丰度均高于非根际土壤,这进一步凸显根际环境在ARGs和MGEs分布中的重要性。此外,还发现在不同地区的稻田土壤中,抗生素失活机制在ARGs中占据主导地位。综上所述,试验结果为深入了解东北水稻种植区稻田土壤中ARGs的污染现状及其潜在影响提供了数据支持和理论基础。这些发现不仅有助于认识农田土壤中ARGs和MGEs的分布与迁移规律,还为制定针对性的土壤污染防控措施提供了科学依据。

Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics

AIM To evaluate the role of biofilm formation on the resistance of Helicobacter pylori(H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.METHODS A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction(PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR(qP CR) analysis was performed using 16 S r RNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.RESULTS The strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidalconcentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qP CR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.CONCLUSION The present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.

Identification and characterization of integron mediated antibiotic resistance in pentachlorophenol degrading bacterium isolated from the chemostat

A bacterial consortium was developed by continuous enrichment of microbial population isolated from sediment core of pulp and paper mill effluent in mineral salts medium（MSM） supplemented with pentachlorophenol（PCP） as sole source of carbon and energy in the chemostat.The consortia contained three bacterial strains.They were identified as Escherichia coli,Pseudomonas aeruginosa and Acinetobacter sp.by 16S rRNA gene sequence analysis.Acinetobacter sp.readily degraded PCP through the formation of tetrachloro-p-hydroquinone（TecH）,2-chloro-1,4-benzenediol and products of ortho ring cleavage detected by gas chromatograph/mass spectrometer（GC-MS）.Out of the three acclimated PCP degrading bacterial strains only one strain,Acinetobacter sp.showed the presence of integron gene cassette as a marker of its stability and antibiotic resistance.The strain possessed a 4.17 kb amplicon with 22 ORF＇s.The plasmid isolated from the Acinetobacter sp.was subjected to shotgun cloning through restriction digestion by BamHI,HindIII and SalI,ligated to pUC19 vector and transformed into E.coli XLBlue1α,and finally selected on MSM containing PCP as sole source of carbon and energy with ampicillin as antibiotic marker.DNA sequence analysis of recombinant clones indicated homology with integron gene cassette and multiple antibiotic resistance genes.

Streptococcus peumoniae in an Egyptian urban community:incidence of erythromycin-resistance determinants and antibiotic susceptibility profile

Objectives:To determine the incidence of resistance of Streptococcus(Strep).pneumoniae isolated in our locality to erythromycin,to screen for the two resistance determinants erm(B) and mef(A) genes,and to identify the susceptibility profile to commonly used antibiotics.Methods:Samples were collected from patients attending the Outpatient Department of Zagazig University Hospital,Zagazig,Egypt,between February 2006 and March 2007.Strep.pneumoniae was identified by conventional procedures.Susceptibilities to erythromycin and 15 antibiotics were identified by disc diffusion method,as outlined by CLSI.E-test was used for MIC determination of erythromycin.erm(B) and mef(A) genes were detected by PCR.Results:Eighty-one Strep. pneumoniae strains were identified.Fifty- one of them(63%) were erythromycin-resistant,and mef(A) gene was the predominant resistance determinant.Vancomycin,imipenem and gatifloxacin had the best activity against the isolates,whereas tetracycline had the least.Forty-two(51.85%) out of the 81 Strep.pneumoniae strains were multidrug-resistant.Conclusions:High incidence of resistance to erythromycin and multiple antimicrobials existed.mef(A) was the principal erythromycin-resistance gene.

Extended role for insertion sequence elements in the antibiotic resistance of Bacteroides

The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence(IS) elements, which are usually regarded as representatives of ‘selfish' genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A(penicillin and cephalosporin), cfx A(cephamycin), cfi A(carbapenem), nim(metronidazole) and erm F(clindamycin) resistance genes. This is achieved by outwardoriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.

Frequency of Antibiotic Resistance of <i>Escherichia coli</i>and <i>Klebsiella pneumoniae</i>by Production of TOHO-Type <i>β</i>-Lactamases at Saint Camille Hospital, Ouagadougou (Burkina Faso)

Extended-spectrum β-lactamase (ESBL) appeared some years after the introduction in hospital environment of unhydrolysable or extended-spectrum cephalosporins. Several studies have been reported on the blaTEM, blaCTX-M and blaSHV genes in ESBL producing Enterobacteria, however, very few studies reported in the literature were related to blaCTX-M subgroup blaTOHO. TOHO enzymes were responsible for healthcare-associated infections in hospitals and in the community. In Burkina Faso, data related to these types of enzymes were scarce. The purpose of this study was to detect TOHO enzymes in Escherichia coli and Klebsiella pneumoniae in order to know the prevalence of infections related to bacterial resistance due to TOHO enzymes at Saint Camille Hospital of Ouagadougou (Burkina Faso). The study was conducted firstly by microbiological identification of ESBLs-producing by Escherichia coli and Klebsiella pneumoniae using API 20 E gallery;secondly the antibiogram was performed by the diffusion method and finally the molecular characterization was made by conventional PCR to search for the blaTOHO gene. The visualization of the specific bands was made using the ultraviolet lamp (Gene Flash) for the photography of the gels. Data were entered and analyzed using Excel 2013 and EPI Info version 6.0 software. A p-value < 0.05 was considered as significant. We obtained at all 39 strains constituted by 21 (53.8%) Escherichia coli and 18 (46.2%) Klebsiella pneumoniae. Molecular characterization showed the presence of the blaTOHO gene in 25 bacterial strains (64.1%). It was therefore established in this study the existence of blaTOHO gene at Saint Camille Hospital in Ouagadougou in Burkina Faso. Our study made it possible to know the distribution of the blaTOHO gene in Escherichia coli and Klebsiella pneumoniae.

辽宁省主要设施农业集散地大棚土壤ARGs与MGEs分布特征分析

为分析设施农业集散地大棚土壤中抗生素抗性基因(antibiotic resistance genes,ARGs)污染与可移动基因元件(mobile genetic elements,MGEs)的分布特征,于辽宁省6个主要设施农业集散地采集温室大棚土壤样品进行实验分析。由于长期施用畜禽粪肥,致使土壤中ARGs的相对丰度和多样性显著增加。对采样点的土壤进行ARGs及MGEs种类和丰度的检测,并对其相关性进行分析。结果表明:土壤样品中检测出50种ARGs和10种MGEs,其中tetG-01、tetG-02、tetM-01、tetM-02、tetPA、tetPB-03、tetT、oprJ、acrA-04、sul2、dfrA1、folA、blaTEM、fox5、ermX、ermB、ermF、ermT-02以及intI-1、tnpA-01、tnpA-05的检出率为100%,且抗性机制主要为细胞保护;土壤中部分ARGs的相对丰度与MGEs的相对丰度之间存在一定的正相关。

Mitigating microbiological risks of potential pathogens carrying antibiotic resistance genes and virulence factors in receiving rivers:benefits of wastewater treatment plant upgrade

Wastewater treatment plants(WWTPs)with additional tertiary ultrafiltration membranes and ozonation treatment can improve water quality in receiving rivers.However,the impacts of WWTP upgrade(WWTP-UP)on pathogens carrying antibiotic resistance genes(ARGs)and virulence factors(VFs)in rivers remain poorly understood.In this study,ARGs,VFs,and their pathogenic hosts were investigated in three rivers impacted by large-scale WWTP-UP.A five-year sampling campaign covered the periods before and after WWTP-UP.Results showed that the abundance of total metagenome-assembled genomes(MAGs)containing both ARGs and VFs in receiving rivers did not decrease substantially after WWTP-UP,but the abundance of MAGs belonging to pathogenic genera that contain both ARGs and VFs(abbreviated as PAVs)declined markedly.'Genome-resolved metagenomics further revealed that WWTP-UP not only reduced most types of VFs and ARGs in PAVs,but also effectively eliminated efflux pump and nutritional VFs carried by PAVs in receiving rivers.WWTP-UP narrowed the pathogenic host ranges of ARGs and VFs and mitigated the cooccurrence of ARGs and VFs in receiving rivers.These findings underline the importance of WWTPUP for the alleviation of pathogens containing both ARGs and VFs in receiving rivers。