重症监护病房耐碳青霉烯类肺炎克雷伯菌分子流行病学研究

 目的 分析重症监护病房(ICU)临床来源耐碳青霉烯肺炎克雷伯菌(CRKP)的分子特征及流行情况,为感染控制及药物治疗提供实验室数据。方法 收集2018年7月-2020年7月某院ICU分离的51株CRKP,采用微量肉汤稀释法测定最低抑菌浓度,多位点序列分型和脉冲场凝胶电泳分析菌株同源性,检测菌株耐药和毒力基因,接合试验验证质粒的转移性。结果 药敏试验显示,CRKP对头孢他啶/阿维巴坦全部敏感,对替加环素耐药率最低(3.9%),其次是阿米卡星(49.0%)、多粘菌素(64.7%),对亚胺培南(96.1%)、美罗培南(98.0%)、左氧氟沙星(98.0%)和头孢他啶(100.0%)均高度耐药。51株CRKP中,mCIM试验阳性菌株49株(96.1%),eCIM试验阳性菌株1株(2.0%)。碳青霉烯酶基因bla_KPC-2阳性菌株占96.1%。所有分离株中,高黏液表型阳性4株(7.8%),毒力基因阳性情况分别为:uge 100.0%,mrkD 94.1%,kpn 94.1%,fim-H 72.5%,aero 2.0%,rmpA 2.0%。ST11 CRKP在ICU中占98.0%(50/51),ST1373占2.0%(1/50)。检出1株ST1373的高毒力肺炎克雷伯菌。携带bla_KPC-2基因菌株的接合试验成功率为12.2%。结论 ICU存在产KPC-2的ST11 CRKP单克隆传播,同时携带一定的毒力基因。携带bla_KPC-2基因的质粒可通过接合水平传播。头孢他啶/阿维巴坦对CRKP有较高的敏感性,可供临床治疗选择使用。

Molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae in intensive care unit

Objective To analyze the molecular characteristics and prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKP)isolated from the intensive care unit(ICU),and provide laboratory data for infection control and antimicrobial treatment.Methods 51 CRKP strains isolated from ICU of a hospital from July 2018 to July 2020 were collected,minimum inhibitory concentration(MIC)was determined by broth microdilution method,homology of strains was analyzed by multi-locus sequence typing(MLST)and pulsed-field gel electrophoresis(PFGE),resis-tance and virulence genes of strains were detected,transferability of plasmid was verified with conjugation testing.Results Antimicrobial susceptibility testing showed that CRKP strains were all susceptible to ceftazidime/avibactam,resistance rate to tegacyclin was the lowest(3.9%),followed by amikacin(49.0%)and polymyxin(64.7%),while strains were all highly resistant to imipenem(96.1%),meropenem(98.0%),levofloxacin(98.0%)and ceftazidime(100.0%).Among 51 CRKP strains,49 strains(96.1%)were positive in mCIM testing,1 strain(2.0%)was positive in eCIM testing.Carbapenemase gene blaKPC-2 positive strains accounted for 96.1%.Among all isolates,4 strains(7.8%)exhibited the hypermucoviscous phenotype,positive rates of virulence genes were uge(100.00%),mrkD(94.1%),kpn(94.1%),fim-H(72.5%),aero(2.0%),and rmpA(2.0%).ST11 and ST1373 CRKP accounted for 98.0%(50/51)and 2.0%(1/50)respectively among ICU strains.One highly virulent Klebsiella pneumoniae strain ST1373 was isolated.The success rate of conjugation testing of blaKPC-2-harboring strains was 12.2%.Conclusion There is a monoclonal transmission of ST11 CRKP that produces KPC-2 in ICU,and it carries certain virulence genes.The plasmid of blaKPC-2-harboring gene can be transmitted horizontally through conjugation.Ceftazidime/avibactam has high susceptibility to CRKP and can be used in clinical treatment.