A:L1 ST128型鸭源多杀性巴氏杆菌的耐药性及毒力分析

Resistance and Virulence Analysis of Type A:L1 ST128 Pasteurella multocida from Ducks

旨在阐明贵州某规模化鸭场临床疑似鸭霍乱的病原菌耐药性及毒力特征,通过细菌的分离鉴定、多位点序列分型(MLST)、ERIC-PCR同源性分析、药敏试验、动物回归试验、细菌全基因组测序以及基因组局部比较分析对分离株进行系统研究。结果显示,分离得到5株鸭源多杀性巴氏杆菌(PmCW1~5),均为A:L1 ST128型且同源性较高;分离株均对氨苄西林、阿莫西林、左氧氟沙星和林可霉素4种药物耐药,其中PmCW1还对环丙沙星低水平耐药;对强毒株PmCW1的全基因组数据分析显示,PmCW1中存在β-内酰胺类、喹诺酮类、四环素类、大环内酯类和多肽类等耐药基因,同时存在多药外排泵及多药耐药蛋白基因,耐药表型与耐药基因检测结果基本相符;PmCW1中存在的毒力基因总数为201个,主要是脂寡糖/脂多糖(LOS/LPS)、荚膜、黏附因子等编码基因;此外,还检测到IV型菌毛基因(ptfA、comE、hofB、hofC、vfr)、铁摄取相关蛋白基因(ccmABCEF、hgbBC、fur、hscB等)以及部分外膜蛋白基因(ompP5等)等;PmCW1具有典型的A:L1型多杀性巴氏杆菌的特征。综上表明,本研究分离得到的ST128型鸭源多杀性巴氏杆菌目前鲜有报道,对其耐药性及毒力的研究可为鸭霍乱的临床用药及疫苗研发提供理论依据。

The aim of this study was to characterize the drug resistance and virulence of pathogens from ducks suspected of cholera in a farm in Guizhou.The pathogenic bacteria were cultured and confirmed by PCR.Capsule genotyping and lipopolysaccharide genotyping,multilocus sequence typing(MLST),ERIC-PCR,animal regression test,drug susceptibility test,whole genome sequencing(WGS)and comparative analysis of local genomes were conducted on those isolated strains.Five Pasteurella multocida isolates(PmCW1-5)were identified as A:L1 ST128 and shared high homology.All of them were resistant to ampicillin,amoxicillin,levofloxacin,and lincomycin.PmCW1 also showed low level resistance to ciprofloxacin.WGS data showed PmCW1 which is highly virulent also harbored genes mediatingβ-lactams,quinolones,tetracyclines,macrolides and peptides resistance and encoding multi-drug efflux pumps and multi-drug resistance proteins.Meanwhile,PmCW1 carried 201 different virulence-mediating genes including those encoding lipooligosaccharide/lipopolysaccharide(LOS/LPS),capsule,adhesion factor,and etc.In addition,type IV fimbriae genes(ptfA,comE,hofB,hofC,vfr),iron uptake related protein genes(ccmABCEF,hgbBC,fur,hscB),outer membrane protein genes(ompP5)were also detected.PmCW1 has the characteristics of typical A:L1 P.multocida.P.multocida ST128 isolated from ducks in this study has been rarely reported.The drug resistance and virulence analysis on those isolates will provide theoretical basis for clinical medication and vaccine development of duck cholera.