肺炎克雷伯菌介导致碳青霉烯类耐药的基因检测研究

目的：分析碳青霉烯类耐药型肺炎克雷伯菌的耐药性及耐药基因型。方法分离碳青霉烯类耐药型肺炎克雷伯菌14株，分别采用E-test实验、改良的Hodge试验、脉冲场琼脂糖凝胶电泳分型及多位点序列分型测定其耐药性、耐药基因型及主要流行序列型。结果14株碳青霉烯类耐药型肺炎克雷伯菌对常用碳青霉烯类抗生素亚胺培南和美罗培南呈中高度耐药，最低抑菌浓度（MIC）分别为8～64 mg/L、16～128 mg/L；对常见头孢类抗生素头孢哌酮、头孢西丁、头孢他啶和头孢吡肟均呈高度耐药，MIC 32～256 mg/L；对喹诺酮类药物环丙沙星呈中度耐药，MIC 3～32 mg/L；对氨基糖苷类抗生素阿米卡星不稳定，MIC〈0.12～256 mg/L。本组碳青霉烯类耐药型肺炎克雷伯菌碳青霉烯酶表型检测均为阳性，基因型属KPC-2；脉冲电泳分型显示A克隆2株、B克隆9株、C克隆3株，多位点序列分型显示ST119株、ST154株、ST4391株，分型结果基本一致。结论碳青霉烯类耐药型肺炎克雷伯菌对部分其他种类的抗生素亦有较强耐药性，KPC-2型碳青霉烯酶是本院肺炎克雷伯菌产生青霉烯类耐药性的主要原因，主要流行克隆型和序列型分别为B型、ST11型。

Genetic testing of carbapenems-resistant Klebsiella pneumoniae

Objective To analyze the antibiotic resistance and genotype of Klebsiella pneumoniae （KNP） resistant to carbapenems. Methods 14 strains of Klebsiella pneumonia resistant to carbapenems were separated. The antibiotic resistance capacity, drug-resistant phenotype and genic sequence type were detected with E-test, reformative Hodge-test, pulsed-field gel electrophoresis （PFGE） and multilocus sequence typing （MLST）. Results The MICs of KNP to imipenem and meropenem were 8～64 mg/L and 16～128 mg/L respectively, with moderate to high antibiotic resistance capacity to carbapenems. The antibiotic resistance capacities to cefoperazone, cefoxitin, ceftazidime and cefepime were all high with MIC of 32～256 mg/L, and to ciprofloxacin it showed a moderate antibiotic resistance capacity with MIC of 3～32 mg/L,while to amikacin, it is unstable with MIC of 0.38～256 mg/L. All 14 stains of KNP could produce Klebsiella pneumoniae carbapenemase 2 （KPC-2）. PFGE results showed cloning types of A （n=2）, B （n=9） and C （n=3）. Meanwhile, MLST results showed ST types of ST11 （n=9）, ST15 （n=4） and ST439 （n=1）. Conclusion Carbapenems-resistant KNP also resists to some other kinds of antibiotics, and KPC-2 is the primary cause of that resistance in our hospital, where the major epidemic cloning and sequence types are type B and type ST11 respectively.