血流感染肺炎克雷伯菌pLVPK毒力质粒的分布及与耐药的关系

Study on the relationship between the distribution of the virulence plasmid pLVPK and the resistance in Klebsiella pneumoniae causing bloodstream infections

目的了解血流感染肺炎克雷伯菌中pLVPK毒力质粒的分布情况,分析其与荚膜血清分型及耐药之间的关系。方法收集医院2016年1月一2017年6月所有非重复血流感染的肺炎克雷伯菌96株,使用Vitek-Compact全自动微生物分析系统进行菌株鉴定及药物敏感性分析;PCR方法检测6种常见高毒力荚膜血清型、7种常见毒力基因、13种常见耐药基因及毒力质粒pLVPK相关基因,使用X2检验进行统计学分析。结果血流感染肺炎克雷伯菌株中携带pLVPK毒力质粒率39.6%。其中毒力质粒pLVPK阳性菌株K1荚膜血清分型率显著高毒力质粒pLVPK阴性菌株(P<0.05),而在其他非高毒力荚膜血清分型上,毒力质粒pLVPK阳性菌株显著低于毒力质粒pLVPK阴性菌株(P<0.05)。pLVPK毒力质粒阳性菌株的毒力基因携带率均显著高于pLVPK毒力质粒阴性菌株(P<0.05)。而pLVPK毒力质粒阳性菌株在耐药性则显著低于pLVPK毒力质粒阴性菌株(P<0.05),其中pLVPK毒力质粒阳性菌株对blaKPC、blaTEM、blaCTX-M、qnB及acc(6')-Ib-cr基因的携带显著低于pLVPK毒力质粒阴性菌株(P<0.05)。结论pLVPK毒力质粒主要集中在K1荚膜血清分型血流感染肺炎克雷伯菌株,pLVPK毒力质粒与毒力基因的携带成正相关,而pLVPK毒力质粒也直接影响了血流感染菌株的耐药性及耐药基因的携带。

Objective To investigate the distribution of virulence plasmid pLVPK in Klebsiella pneumoniaecausing bloodstream infections, and analyze the relationship between the virulence plasmid pLVPK and the serotypeand resistance. Methods Ninety-four non-repetitive Klebsiella pneumoniae were were collected from the FirstAffiliated Hospital of Nanchang University from January 2016 to June 2017. The bacteria identification and drugsusceptibility was identified with the Vitek 2 compact system. The capsular serotypes, resistance genes and virulencefactors were detected by polymerase chain reaction and DNA sequencing. Results The carriage rate of the virulenceplasmid pLVPK in Klebsiella pneumoniae causing bloodstream infections was 39.6%. The carriage rates of thevirulence plasmid pLVPK in the K1 serotype strains were significantly higher, while the non-hyperviurlent serotypesstrains were significantly lower (P<0.05). The carriage rates of the virulence genes in the pLVPK positive strains weresignificantly higher than the pLVPK negative strains (P<0.05). However, the resistant rates of the virulence genes in the pLVPK positive strains were significantly lower than the pLVPK negative strains (P<0.05). Among them, the carriage rates of blaKPC、blaTEM、blaCTX-M、qnB and acc( 6 ')-Ib-cr gene in the pLVPK positive strains were significantly lower than the pLVPK negative strains (P<0.05). Conclusions The virulence plasmid pLVPK was mainly located in the K1 capsule serotype in Klebsiella pneumoniae causing bloodstream infections in our hospital. Its carriage was positively correlated with the virulence genes, while the virulence plasmd pLVPK also directly affects the resistance and resistant genes carriage in Klebsiella pneumoniae causing bloodstream infections.