105例呼吸机相关性肺炎患者肺炎克雷伯菌临床与微生物学特征分析

Clinical and Microbiological Characteristics of Klebsiella pneumoniae Ventilator-associated Pneumonia:A Retrospective Study of 105 Cases

目的分析呼吸机相关肺炎(VAP)患者下呼吸道分离所得肺炎克雷伯菌的临床及微生物学特征。方法回顾性分析2013年1月至2018年12月在河南省人民医院确诊的105例呼吸机相关肺炎患者的临床特征,同时对分离的105例肺炎克雷伯菌进行分子生物学研究。以PCR方法检测主要荚膜血清型和毒力基因,多位点序列分析(MLST)方法对菌株进行同源性分析。结果24.8%(26/105)的肺炎克雷伯菌呼吸机相关肺炎是由高黏液性菌株引起。与经典肺炎克雷伯菌相比,高黏液性肺炎克雷伯菌感染更容易引起患者菌血症与高死亡率。高黏液性肺炎克雷伯菌中,毒力基因rmpA、aerobactin检出率均为88.5%,血清型K1与K2的检出率分别为15.4%与26.9%。相关性分析表明rmpA、aerobactin基因表达与高黏液性肺炎克雷伯菌表型呈正相关,并且rmpA与aerobactin基因同时存在于高黏液性肺炎克雷伯菌中。共发现3株产超广谱β内酰胺酶(ESBLs)的高黏液性肺炎克雷伯菌菌株。在105例肺炎克雷伯菌院内感染病例中,多位点分析鉴定出24种不同的ST分型。结论高黏液性肺炎克雷伯菌已经成为院内感染呼吸机相关肺炎的常见致病菌,其中包括产ESBLs的高黏液性肺炎克雷伯菌,应引起临床医师高度重视,采取有效措施控制其传播。

Objective The purpose of this study was to investigate the clinical characteristics of Klebsiella pneumoniae(K.pneumoniae)-associated ventilator-associated pneumonia(VAP)and the molecular characteristics of K.pneumoniae strains.Methods We retrospectively reviewed 105 mechanically ventilated patients with K.pneumoniae collected from Henan Provincial People’s Hospital from January 2013 to December 2018.The molecular characteristics of the K.pneumoniae strains were examined using PCR and multilocus sequence typing methods.Results Hypermucoviscous K.pneumoniae(hvKP)was found in 26 of 105(24.8%)isolates of K.pneumoniae.Hypermucoviscous strains-associated infection was inclined to develop bacteremia and had a higher mortality rate than classic K.pneumoniae strains infection.The prevalence of rmpA and aerobactin genes was 88.5%and 88.5%,respectively,and serotypes K1 and K2 accounted for 15.4%and 26.9%of the hypermucoviscous strains,respectively.Strains carrying rmpA and aerobactin genes were significantly associated with hypermucoviscous phenotype,and rmpA and aerobactin coexisted in hypermucoviscous strains.Three ESBLs-producing hvKP strains were found.Multilocus sequence typing analysis identified 24 different sequence types from 105 strians of K.pneumoniae.Conclusion The emerging hypermucoviscous K.pneumoniae was prevalent in patients with hospital-acquired infection.Three ESBLs-producing hvKP strains were identified.Clinicians should pay attention to hvKP-induced VAP and take effective strategy to control infection caused by hvKP.