血流感染CRKP的临床特点及高毒力血清型分析

Analysis of the clinical characteristics and hypervirulent serotype of CRKP bloodstream infections

目的了解耐碳青霉烯肺炎克雷伯菌(carbapenemresistant Klebsiella pneumoniae,CRKP)血流感染的临床特点及高毒力血清型的分布情况。方法收集我院2016年11月—2017年9月血培养标本分离出的非重复CRKP22株,采用美国BD公司生产的Phonenix-100全自动细菌鉴定/药敏系统进行菌株鉴定和药敏试验,药敏试验同时联合纸片扩散法(KB法),改良Hodge试验筛查碳青霉烯酶表型。采用PCR方法及基因测序检测肺炎克雷伯菌的体外溶血酵素基因khe、2种常见耐药基因(blaKPC、blaIMP)和6种高毒力血清型(K1、K2、K5、K20、K54、K57)。结果22例CRKP有5例存活,17例死亡,死亡率达77.3%;科室分布主要在重症医学科(59.1%),神经内科重症病房(22.7%),泌尿外科(9.1%),血液科(4.5%)等。PCR测序显示22株CRKP有17株检出blaKPC基因,未检出blaIMP基因;高毒力血清型检测结果为K1型1株(占4.5%),K5型2株(占9.1%),K20型2株(占9.1%),主要分布在不携带blaKPC基因的菌株中。22株CRKP对亚胺培南和美罗培南的耐药率为100%,对替加环素和多黏菌素的敏感率高达100%,毒力菌株与非毒力菌株对复方磺胺甲噁唑的耐药率差别不大,分别为60.0%和52.9%,但对阿米卡星和庆大霉素的耐药率差别较大,表现为毒力菌株的耐药率低于非毒力菌株。结论我院流行的CRKP血流感染菌株主要分离自重症医学科和神经内科重症病房患者,且死亡率较高;毒力菌株与非毒力菌株对氨基糖苷类抗生素的耐药情况有差别,临床在治疗过程中应区别对待,并加强防控。

Objective To investigate the clinical characteristics and the distribution of hypervirulent serotype of CRKP bloodstream infections.Methods A total of 22 non-repeated CRKP isolates from blood culture between November 2016 and September 2017 were collected in our hospital.Identification and drug resistance were tested by the BD Phoenix-100 system combined with the K-B method.The Modified Hodge Test was used for the screening of carbapenemase.The gene khe,two common drug resistant genes(blaKPC and blaIMP)and six hypervirulent serotypes(K1,K2,K5,K20,K54,and K57)were detected by PCR.Results Among the 22 patients with CRKP five cases were survived,and 17 cases were dead,with the fatality rate of 77.3%.Most of the patients were in the intensive care unit(59.1%),neurological intensive care unit(22.7%),the department of urology(9.1%),and the department of hematology(4.5%).PCR results showed that the blaKPC gene wasfound in 17 isolates,but the blaIMP gene wasnot detected.Three kinds of hypervirulent serotype were detected,including one isolate of K1(4.5%),two isolates of K5(9.1%),and two isolates of K20(9.1%),mainly distributed in isolates without the blaKPC gene.The resistance rates of 22 CRKP to imipenem and meropenem were 100%.All of them were most sensitive to tigecycline and colistin,and the sensitive rates were 100%.There was a slight difference between hypervirulent and avirulent isolates in resistance rates to cotrimoxazole,which were 60.0%and 52.9%,respectively.However,the difference was big to amikacin and gentamicin,and the resistance rates of hypervirulent isolate were lower than avirulent isolates.Conclusion 22 CRKP isolates from blood culture in our hospital were mainly collected from ICU and NICU,with high fatality rates;the difference between hypervirulent and avirulent isolates in aminoglycoside antibiotic resistance rates was big,and therefore clinical doctors should treat them differently.Meanwhile,prevention and control measures should be used for CRKP bloodstream infections.