Guo Ling, An Jingna, Ma Yanning, Ye Liyan, Luo Yanping, Tao Chuanmin, Yang Jiyong
Department of Microbiology, Chinese PLA General Hospital, Beijing, China.
Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China.
PLoS One. 2016 Aug 4;11(8):e0160754. doi: 10.1371/journal.pone.0160754. eCollection 2016.
In China, the spread and outbreak of OXA-48-producing Enterobacteriaceae remains largely unknown.
OXA-48-producing isolates were analyzed for genetic relatedness by pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility by E-test, and sequence type (ST) by multilocus sequence typing. S1-PFGE and southern blotting were used for plasmid profiling, and PCR and subsequent sequencing were performed to determine the genetic environment of blaOXA-48 gene.
In total, 37 non-duplicated OXA-48-producing K. pneumoniae (OXAKp) isolates were recovered. From December 2013 to August 2014, an outbreak was observed at a respiratory ICU. The 37 isolates of K. pneumoniae were categorized into four PFGE types (A, B, C, and D). The predominant strains associated with the outbreak were strains with PFGE type A and B, which belonged to ST383 and ST147, respectively. Plasmid sequencing revealed that the blaOXA-48-carrying plasmid is 69,069 bp in length and belongs to the IncL/M incompatibility group. Sequence analysis revealed that the IS1999 element was located upstream of the blaOXA-48 gene and was truncated by IS1R.
In this study, the dissemination and outbreak of OXAKp isolates were clonal, and ST147 and ST383 K. pneumoniae were the predominant clones that were associated with the outbreak. Meanwhile, the horizontal transfer of plasmids potentially mediate the spread of blaOXA-48 gene between different K. pneumoniae strains.
在中国，产OXA - 48型肠杆菌科细菌的传播和暴发情况仍 largely未知。
通过脉冲场凝胶电泳（PFGE）分析产OXA - 48型分离株的遗传相关性，采用E-test法检测抗菌药物敏感性，通过多位点序列分型确定序列类型（ST）。利用S1 - PFGE和Southern印迹法进行质粒图谱分析，并通过PCR及后续测序确定blaOXA - 48基因的遗传环境。
共分离出37株非重复的产OXA - 48型肺炎克雷伯菌（OXAKp）分离株。2013年12月至2014年8月期间，在呼吸重症监护病房观察到一次暴发。这37株肺炎克雷伯菌分离株分为四种PFGE型（A、B、C和D）。与暴发相关的主要菌株是PFGE型A和B的菌株，分别属于ST383和ST147。质粒测序显示，携带blaOXA - 48的质粒长度为69,069 bp，属于IncL/M不相容群。序列分析表明，IS1999元件位于blaOXA - 48基因上游，并被IS1R截断。
在本研究中，OXAKp分离株的传播和暴发是克隆性的，ST147和ST383肺炎克雷伯菌是与暴发相关的主要克隆。同时，质粒的水平转移可能介导blaOXA - 48基因在不同肺炎克雷伯菌菌株之间的传播。
