CRKP血流感染危险因素和耐药及毒力特征

Risk factors for CRKP bloodstream infection, drug resistance and virulence characteristics

目的分析碳青霉烯类耐药肺炎克雷伯菌(CRKP)血流感染危险因素、耐药及毒力特征。方法收集南昌大学第一附属医院从血液中分离的肺炎克雷伯菌(KP)248株,采用全自动微生物分析仪进行生化鉴定和药敏试验,根据药敏结果分为CRKP组73株,碳青霉烯类敏感的肺炎克雷伯菌(CSKP)组175株。病例系统查询两组KP血流感染患者所对应的临床资料,聚合酶链反应(PCR)检测两组菌株的耐药基因、荚膜血清型基因和毒力基因。结果多因素Logistic回归分析显示肾脏疾病、烧伤、机械通气、留置导尿管、留置引流管、碳青霉烯类抗菌药物使用和替加环素使用是碳青霉烯类抗菌药物耐药的独立危险因素(P<0.05)。血流感染中CRKP组患者病死率53.42%高于CSKP组患者(P<0.05)。CRKP组对15种抗菌药物的耐药率均大于CSKP组(P<0.05)。73株CRKP菌株中检测出KPC基因69株,阳性率为94.52%;NDM基因4株,阳性率为5.48%;其中有1株同时携带KPC和NDM基因。CRKP组检出3株K1型、2株K2型、1株K20型、2株K54型。结论本研究血流感染中CRKP菌以KPC为主,但也存在NDM的流行。CRKP菌株多药耐药情况严重,患者病死率高,并且出现高毒力血清荚膜分型。临床应针对CRKP血流感染独立危险因素,加以干预和控制。

OBJECTIVE To investigate the risk factors for carbapenem-resistant Klebsiella pneumoniae(CRKP) bloodstream infection and analyze the drug resistance and virulence characteristics. METHODS A total of 248 strains of Klebsiella pneumoniae were isolated from blood specimens of the First Affiliated Hospital of Nanchang University. The biochemical identification and drug susceptibility testing were performed by using automatic microorganism analysis system, the strains were divided into the CRKP group with 73 strains and the CSKP(carbapenem-sensitive K.pneumoniae) group with 175 strains according to the result of drug susceptibility testing. The clinical data corresponding to the patients with K.pneumoniae bloodstream infection were searched by case system. The drug resistance genes, capsular serotypes and virulence genes were detected by means of polymerase chain reaction(PCR). RESULTS Multivariate logistic regression analysis showed that the renal disease, burn wound, mechanical ventilation, urinary catheter indwelling, drainage tube indwelling, carbapenems and tigecycline were the independent risk factors for the resistance to carbapenems(P<0.05). The mortality rate of the patients with bloodstream infection was 53.42% in the CRKP group, significantly higher than that in the CSKP group(P<0.05). The drug resistance rates to 15 types of antibiotics were significantly higher in the CRKP group than in the CSKP group(P<0.05). 69 of 73 CRKP strains were detected with KPC gene, with the positive rate 94.52%;4 strains were detected with NDM gene, with the positive rate 5.48%;1 strain was detected with both KPC gene and NDM gene. There were 3 strains of K1, 2 strains of K2, 1 strain of K20 and 2 strains of K54 in the CRKP group. CONCLUSION The CRKP strains carrying with KPC gene are dominant among the patients with bloodstream infection, NDM gene is also prevalent. The CRKP strains are highly multidrug-resistant, the mortality rate is high, and highly virulent capsular serotypes have emerged. It is necessary for the hospital to take targeted intervention measures according to the independent risk factors for the CRKP bloodstream infection.