北京某医院感染性腹泻患者致泻性大肠埃希菌毒力和耐药特征分析*

目的 明确本院感染性腹泻患者致泻性大肠埃希菌毒力和耐药特征。方法 采用VITEK MS微生物质谱检测系统初步鉴定,多重实时荧光PCR检测毒力基因,对本院感染性腹泻患者临床分离的致泻性大肠埃希菌(Diarrheagenic Escherichia coli, DEC)进行5种型别鉴定。微量肉汤稀释法和E-test法药敏试验检测DEC菌株的耐药表型特征。二代测序及生物信息学分析其耐药分子特征。采用Fisher确切概率法进行统计学分析。结果 本院DEC检出率为11.9%,其中EAEC占比37.5%,非典型EPEC占比34.38%,ETEC占比25.0%,EIEC占比3.12%,未检出EHEC菌株。32株DEC对氨苄西林、四环素、甲氨苄啶/磺胺异恶唑耐药率最高,分别为53.12%、43.75%和37.5%。ESBLs(+)株占比18.75%,其多重耐药菌株检出率为83.83%,显著高于ESBLs(-)菌株,差异有统计学意义(P=0.042)。32株DEC共有25个ST型,优势基因型为ST10共4株(12.5%),ST28、ST31和ST3153各2株(各占比6.25%),其他21个型别各1株菌...

Analysis of virulence and drug resistance characteristics of diarrheagenic Escherichia coli isolated from patients with infectiousdiarrhea in a hospital in Beijing

Abstract : Objective ''To investigalte the virulence and drug resistance characteristics of diamheagenic Escherichia coli isolated frompatients with infectious diarrhea in our hospital. MethodsThe preliminary identification of microbes was carried out by the VITEK-MSmicrobial mass spectrometry detection system and virulence genes were detected by the muliplex real-time PCR. Five types of diarrheargenic Escherichia coli (DEC) clinically isolated from patients with infectious diarrhea in our hospial were identified. The drng resist-ance characteristics of DEC strains were detected by the microbroth dilution and E-test. The drug-resistant molecular characteristicswere analyzed by the next-generation sequencing and bioinformatics. The Fisher exact probability method was used for statistical analy-sis.Results The detection rate of DEC in our hospital was 11.9% ,with enteroaggregative E.coli(EAEC) accounting for 37.5% , a-typical enteropathogenic Escherichia coli (EPEC) accounting for 34.38% , enterotoxigenic E. coli (ETEC) accounting for 25.0% , andenteroinvasive E.coli (EIEC) accounting for 3.12%. None of enterohemorhagic E. coli (EHEC) strain was detected. The resistancerales of 32 DEC strains to ampicillin, tetracyeline,and trimethoprim/sulfamethoxazole were 53.12%,43.75%, and 37.5%6 , respec-tively.ESBLs ( +) strains accounted for 18.75% , and the detection rate of multidrug-resistant strains was 83.83% , significantly higherthan that of ESBLs ( -) strains ( P=0.042).A total of 25 ST genotypes were obtained from 32 DEC strains. The dominant genotypeswere ST10 (4 strains,12.5% ) , followed by ST28 (2 strains , 6.25% ) , ST31(2 strains , 6.25%) , ST3153 (2 strains ,6.25% ) , andthe other 2l genotypes ( l strain,3.13% ) . One carbapenem resistant strain carrying the bla DM. gene was detected in EAEC.Conclu-sion Four vinulence genes such as aggR , pic , astA , and eae , are more common in the DEC of patients with infectious diarrhea in ourhospital ,with EAEC and EPEC as the main subhtypes. The genotypes are highly polymorphic , and mulidnug-resistant strains have been detected.