2015-2018年黏菌素耐药肺炎克雷伯菌的分子流行病学研究

Molecular epidemiology of colistin resistant Klebsiella pneumoniae isolates from 2015-2018

目的对黏菌素耐药肺炎克雷伯菌的分子流行病学进行调查。方法通过琼脂稀释法和微量肉汤稀释法测定中国细菌耐药监测研究(CARST)于2015-2018年收集的肺炎克雷伯菌的最低抑菌浓度;通过聚合酶链反应和Sanger测序检测黏菌素相关耐药基因;通过接合实验验证mcr-1和mcr-8所在质粒的水平传递性;通过多位点序列分型对黏菌素耐药菌株进行同源性分析。结果共有29株肺炎克雷伯菌对黏菌素耐药。其中,5株携带mcr-1,4株携带mcr-8,15株菌存在双组分系统基因突变;2株mcr-1阳性菌株和1株mcr-8阳性菌株可以通过接合实验使大肠埃希菌J53获得黏菌素抗性。29株黏菌素耐药肺炎克雷伯菌分属23个ST型,彼此无明显关联。结论黏菌素作为多重耐药肺炎克雷伯菌的少数治疗选择之一,应及时采取措施阻止其耐药情况加剧。

Objective To investigate the molecular epidemiology of colistin resistant Klebsiella pneumoniae isolates. Methods Klebsiella pneumoniae isolates were collected by China Antimicrobial Resistance Surveillance Trial(CARST) from 2015-2018. Antibacterial susceptibility test was performed by agar dilution method and microdilution broth method. Colistin resistance genes were detected by polymerase chain reaction(PCR) and Sanger sequence. Conjugation experiment was performed to verify the transferability of plasmids carrying mcr-1 or mcr-8. Homology analysis was performed by Multilocus sequence typing(MLST). Results There were 29 Klebsiella pneumoniae isolates resistant to colistin. Five isolates carried mcr-1 and 4 isolated carried mcr-8, the two-component system gene mutations were found in 15 isolates. Two mcr-1 positive isolates and 1 mcr-8 positive isolate succeed to transfer colistin resistance to Escherichia. coli J53. Twenty-nine colistin resistant Klebsiella pneumoniae isolates belonged to 23 ST types. Conclusion As one of the few treatment options for multidrug-resistant Klebsiella pneumoniae, appropriate measures should be taken to prevent increased colistin resistance.