肺炎克雷伯菌中携带碳青霉烯酶KPC-2基因的质粒分型

Plasmids typing of genes carrying bla_(KPC-2) in Klebsiella pneumoniae isolated at a tertiary hospital in Shanghai

目的 :观察华山医院临床耐碳青霉烯类肺炎克雷伯菌中携带bla_(KPC-2)质粒的分型情况,以了解其流行变迁。方法:共收集华山医院临床连续不重复的bla_(KPC-2)阳性碳青霉烯类耐药肺炎克雷伯菌38株,对其进行多位点序列分型(multilocus sequence typing,MLST)分型,并用松弛酶对质粒进行分型。结果:8株肺炎克雷伯菌所携带的bla_(KPC-2)阳性质粒属于MOBP3亚型,另30株均为MOB_(F12)亚型。同时,进化树显示,本批菌株所含有的MOB_(F12)亚型质粒位于2个不同分支上,提示该批菌株的MOB_(F12)亚型质粒具有不同的生物来源。结论:首次运用松弛酶对肺炎克雷伯菌所携带的bla_(KPC-2)阳性质粒进行分型,发现其中8株属于MOBP3亚型,30株为MOB_(F12)亚型,且MOB_(F12)亚型菌株具有不同的生物来源,反映了华山医院临床耐碳青霉烯类肺炎克雷伯菌中携带bla_(KPC-2)质粒的多样性。

Objective: To investigate the plasmids typing of genes carrying blaKPC-2in carbapenemase resistant Klebsiella pneumoniae for exploring its epidemiological evolution. Methods: Thirty-eight carbapenem-resistant Klebsiella pneumoniae isolates obtained consecutively from Huashan Hospital were collected, all carrying blaKPC-2-bearing plasmids.All the strains were subjected to multilocus sequence typing(MLST). Relaxase analysis was used to classify these plas-mids. Results: Eight of the blaKPC-2-bearing plasmids belonged to the MOBP3 and 30 blaKPC-2-bearing plasmids belonged to the MOBF12. Phylogenetic analysis revealed that the MOBF12 plasmids were located at two different branches, respectively,suggesting they had different biological origin. Conclusions: It is the first time that relaxase has been used for plasmids typing of genes carrying blaKPC-2in carbapenemase resistant Klebsiella pneumoniae, and found 8 belonged to the MOBP3and30 belonged to the MOBF12, and the MOBF12 having different biological origin, denoting the epidemiological evolution of blaKPC-2bearing plasmid in carbapenemase resistant Klebsiella pneumoniae.