临床分离的耐碳青霉烯肺炎克雷伯菌的耐药机制研究

摘要

Objective To explore the molecular mechanisms of carbapenem-resistant Klebsiella pneumoniae.Methods Carba NP confirmatory test were used to detect carbapenemases.Carbapenemase genes,ESBL genes and plasmid-mediated AmpC genes were amplified by polymerase chain reaction (PCR).The genetic correlation analysis was carried out by using multiple sequence type (MLST).Results 42 out of the 50 carbapenem-resistant Klebsiella pneumoniae strains were KPC-2-positive strains,1 strain was positive for NDM-1,the other 7 strains were not detected for any carbapenemase genes.The percentages of KPC-2-positive Klebsiella pneumoniae with the bla CTX-M,bla SHV,bla TEM,bla DHA were 21.5 ％,42.9 ％,69.1％ and 4.8％ respectively.The results of MLST showed that 37 out of 42 KPC-2 positive strains were ST11.Conclusion The production of KPC-2 is the main mechanism of Klebsiella pneumoniae resistance to carbapenem and there is an outbreak of ST11 KPC-2 Klebsiella pneumoniae in this hospital.%目的 探究肺炎克雷伯菌对碳青霉烯类抗菌药物耐药的分子机制.方法 通过Carba NP确证试验检测碳青霉烯酶表型;PCR扩增碳青霉烯酶基因,质粒介导AmpC酶基因,超广谱β-内酰胺酶基因;采用多序列位点分型(MLST)对菌株进行遗传相关性分析.结果 50株耐碳青霉烯肺炎克雷伯菌中,42株PCR扩增KPC-2阳性,1株NDM-1阳性,其余7株未检测到碳青霉烯酶基因;产KPC-2肺炎克雷伯菌相关耐药基因的携带率为:bla CTX-M 21.5％,bla SHV 42.9％,bla TEM 69.1％和bla DHA 4.8％;MLST结果显示42株KPC-2阳性菌株中,37株为ST11型.结论 KPC-2的产生是肺炎克雷伯菌对碳青霉烯类抗菌药物耐药的主要机制,且该院存在着ST11产KPC-2肺炎克雷伯菌的暴发流行.