耐碳青霉烯类肠杆菌科细菌的耐药机制探讨

Mechanism of carbapenems-resistant Enterobacteriaceae

目的探讨耐碳青霉烯类肠杆菌科细菌的耐药机制。方法收集上海交通大学附属第六人民医院2011年1月—2013年12月临床分离到的80株碳青霉烯类抗菌药物耐药的肠杆菌科细菌,采用Vitek Compao60鉴定系统进行细菌鉴定和药物敏感性检测,用纸片扩散法检测细菌对亚胺培南和美罗培南的敏感性,用改良Hodge试验、抑制剂的双纸片增效试验检测碳青霉烯酶表型,用聚合酶链反应(PCR)检测blaKPC、blaIMP、blaOXA23、blaOXA51、blaOXA48、blaVIM、blaNMD。结果 80株菌株对常见多种抗菌药物耐药;改良Hodge试验和硼酸抑制试验与KPC酶检测的一致率分别为47.5%和97.5%;blaKPC、blaIMP、blaOXA23、blaOXA51、blaOXA48、blaVIM和blaNMD的检出率分别为88.75%、5.00%、3.75%、3.75%、0.00%、0.00%和0.00%,所有基因均阴性的检出率为5.00%。结论上海交通大学附属第六人民医院肠杆菌科细菌耐碳青霉烯类抗菌药物的主要机制是携带KPC-2型碳青霉烯酶,硼酸抑制试验能快速、准确地检测出KPC酶。

Objective To study the mechanism of carbapenems-resistant Enterobacteriaceae. Methods A total of 80 isolates of Enterobacteriaceae being resistant to carbapenems were isolated from patients in Shanghai Sixth People＆#39;s Hospital from January 2011 to December 2013. The isolates were identified by Vitek Compao60 automatic system,and antimicrobial susceptibility was determined as well. The susceptibilities to imipenem and meropenem were determined Kirby-Bauer disc diffusion method. The modified Hodge test and inhibitor-potentiated double-disc diffusion test were performed for determining carbapenemase phenotype. Polymerase chain reaction（PCR） was performed for determining blaKPC,blaIMP,blaOXA23,blaOXA51,blaOXA48,blaVIM and blaNMD. Results The isolates were resistant to many antibiotics. The consistencies of modified Hodge test and aminophenylboronic acid inhibition test to KPC were 47.5% and 97.5%. The determination rates of blaKPC,blaIMP,blaOXA23,blaOXA51,blaOXA48,blaVIM and blaNMD were 88.75%,5.00%,3.75%,3.75%,0.00%,0.00% and 0.00%. The determination rate of isolates being negative for all the tested genes was 5.00%.Conclusions KPC-2 carbapenemase is the main mechanism of carbapenems-resistant Enterobacteriaceae in Shanghai Sixth People＆#39;s Hospital. The inhibitor-potentiated double-disc diffusion test can determine KPC easily and correctly.