MLST和PFGE在耐碳青霉烯类肺炎克雷伯菌医院感染监测中的应用

Application of MLST and PFGE in the monitoring of carbapenem-resistant Klebsiella pneumoniae healthcare-associated infection

目的探讨某院重症监护病房(ICU)患者、医院环境中耐碳青霉烯类肺炎克雷伯菌(CRKP)菌株的同源性,为医院感染防控提供理论依据。方法收集2017年9—12月某三甲医院ICU患者、环境中连续分离的CRKP菌株,进行耐药表型、碳青霉烯酶基因检测,采用多位点序列分型(MLST)和脉冲场凝胶电泳(PFGE)进行分子同源性分析。结果共收集10株CRKP菌株,其中9株分离自5例患者的临床感染标本,1株分离自气压治疗仪面板。10株菌均携带产KPC酶基因;MLST分型均为ST11型;共有5种PFGE带型,其中5株带型完全一致,为流行菌株,1株菌株与流行菌株带型仅相差1条条带,其余4株菌带型相近,但与流行株带型差异较大。气压治疗仪面板分离的1株CRKP菌株与患者来源的4株CRKP菌株耐药表型、PFGE型别及ST型别完全一致,考虑为仪器共用造成的医院感染。分离自同一重症胰腺炎患者腹腔引流液、血标本的CRKP菌株PFGE带型完全一致,推测CRKP可能通过腹腔感染入血。结论PFGE和MLST对明确医院感染细菌传播路径,个体细菌感染路径以及遗传变异有重要意义,有助于从切断感染途径方面入手指导控制多重耐药菌的传播。

Objective To explore the homology of carbapenem-resistant Klebsiella pneumoniae(CRKP)strains from patients and environment in an intensive care unit(ICU)of a hospital,and provide theoretical basis for the prevention and control of healthcare-associated infection(HAI).Methods CRKP strains continuously isolated from patients and environment in ICU in a tertiary first-class hospital between September and December 2017 were collected,drug resistance phenotype and carbapenemase genes were detected,molecular homology analysis was performed with multilocus sequence typing(MLST)and pulsed-field gel electrophoresis(PFGE).Results A total of 10 strains of CRKP were collected,9 of which were isolated from clinical infection specimens of 5 patients,and 1 was isolated from the panel of the barotherapy instrument.10 strains all carried KPC gene;MLST types were all ST11;there were 5 types of PFGE bands,5 strains had identical bands,which were epidemic strains,1 strain was only 1 band different from epidemic strain,the other 4 strains had similar band types,but they were significantly different from that of the epidemic strain.Drug resistance phenotype,PFGE type and ST type of 1 CRKP strain isolated from panel of barotherapy instrument was identical with 4 CRKP strains from patients,and was considered as HAI due to instrument sharing.PFGE band type of CRKP strains isolated from the abdominal drainage fluid and blood specimen of the same patient were exactly the same,which was speculated that CRKP might be infected bloodstream through the abdominal cavity.Conclusion PFGE and MLST are of great significance to clarify bacteria transmission route of HAI,individual bacterial infection route and genetic variation,which is conductive to cutting off infection route and strongly guiding the control of multidrug-resistant organism transmission.