肺炎克雷伯菌中 K1、K2血清型菌株的分布及其耐药性分析

Distribution and antibiotic resistance of Klebsiella pneumoniae strains in terms of K1 and K2 serotypes

目的了解K1、K2血清型肺炎克雷伯菌、毒性因子rmpA在临床感染中的分布及耐药性。方法拉丝试验确定144株肺炎克雷伯菌黏液表型,用多重聚合酶链反应(PCR)检测K1、K2和rmpA基因。结果 144株不同感染来源的肺炎克雷伯菌中,黏液型菌株占62.5%(90/144);K1、K2血清型阳性率为52.1%(75/144),rmpA阳性率为65.3%(94/144),其中K1、K2血清型与rmpA共同阳性菌株占K1、K2血清型总数的90.7%(68/75)。K1、K2血清型、rmpA基因黏液型和非黏液型菌株分别为63.3%(57/90)、85.6%(77/90)和33.3%(18/54)、31.5%(17/54)。K1、K2血清型肺炎克雷伯菌在有无rmpA基因肺炎克雷伯菌中分别为72.3%(68/94)和14.0%(7/50)。黏液型菌株在42例肝脓肿、16例其他部位脓肿、37例血流感染、14例社区获得性肺炎(CAP)、21例尿路感染(UTI)和14例胆道感染中分别占85.7%(36/42)、81.3%(13/16)、40.5%(15/37)、85.7%(12/14)、52.4%(11/21)和21.4%(3/14)。K1、K2血清型分别为88.1%(37/42)、56.3%(9/16)、29.7%(11/37)、64.3%、(9/14)、38.1%(8/21)和7.1%(1/14)。K1血清型在肝脓肿占61.9%(26/42);K1、K2血清型在其他部位脓肿、CAP、UTI和血流感染中比例相近;非-K1、K2血清型则多见于胆道感染。黏液型和非黏液型菌株产超广谱β内酰胺酶(ESBL)率分别为5.6%和33.3%。前者对多数抗菌药物耐药率低于后者。结论 rmpA基因与肺炎克雷伯菌黏液表型密切相关,并多与K1、K2血清型肺炎克雷伯菌共存,K1、K2血清型肺炎克雷伯菌是肝脓肿和CAP的重要病原菌,在其他部位脓肿、UTI、血流感染也较常见,K1血清型肺炎克雷伯菌在肝脓肿多见,K1、K2血清型肺炎克雷伯菌在其他感染中比例相近。黏液型菌株产ESBL率和对多数抗菌药耐药率低于非黏液型菌株。

Objective To investigate the distribution and antibiotic resistance of the K lebsiella pneumoniae strains isolated from clinical infections in terms of serotypes K1 ,K2 and virulence factor rmpA gene .Methods The hypermucoviscous phenotype of K .pneumoniae isolate was determined by string test .K1 and K2 serotypes and rmpA gene were detected using multiplex polymerase chain reaction .Results Of the 144 strains of K .pneumoniae ,the prevalence of hypermucoviscous phenotype ,K1 , K2 serotypes and rmpA gene was 62 .5% （90/144） ,52 .1% （75/144） and 65 .3% （94/144） ,respectively .The prevalence of K1 ,K2 and rmpA K .pneumoniae strains was 90 .7% （68/75） in K1 ,K2 serotypes .The prevalence of K1 ,K2 isolates and rmpA in hypermucoviscous or non‐hypermucoviscous phenoype was 63 .3% （57/90） ,85 .6% （77/90） and 33 .3% （18/54） , 31 .5% （17/54） ,respectively .The prevalence of serotype K1 ,K2 with or without rmpA gene was 72 .3% （68/94） and 14 .0% （7/50 ） respectively . Of the 42 K . pneumoniae strains isolated from liver abscess ,85 .7% （36/42） were hypermucoviscous phenotype and 88 .1% （37/42 ） were serotypes K1 , K2 . For the strains from other abscess , bacteremia ,community acquried pneumonia （CAP） ,urinary tract infection （UTI） and biliary tract infection ,the prevalence of hypermucoviscous phenotype was 81 .3% （13/16） ,40 .5%（15/37） ,85 .7% （12/14） ,52 .4% （11/21） and 21 .4% （3/14） ,respectively ,and the prevalence of serotypes K1 ,K2 was 56 .3% （9/16） ,29 .7% （11/37） ,64 .3% （9/14） ,38 .1% （8/21） and 7 .1% （1/14） ,respectively .K1 serotype isolate accounted for 61 .9% of the strains from liver abscess .The ratio between serotype K1 and K2 was similar in the isolates from other abscess ,CAP ,UTI or bacteremia .Non‐K1 ,K2 serotype isolates were common in biliary tract infection .The prevalence of extended‐spectrum beta‐lactamases （ESBLs ） was 5 .5% in hypermucoviscous phenotypes and 33 .3% in the non‐hypermucoviscous phenotypes .Conclusions rmpA gene is associated with the hypermucoviscous phenotype of K .pneumoniae strains and commonly identified in K1 ,K2 serotype isolates .Serotypes K1 ,K2 isolates are important pathogens in liver abscess and CAP ,and also common in other abscess ,UTI and bacteremia .K1 serotype isolate was most common in liver abscess .The prevalence of K1 or K2 serotype was similar in other infections . The prevalence of ESBLs is lower in hypermucoviscous strains than in non‐hypermucoviscous strains and is associated with lower resistance rate to most of the antibiotics tested .