Bina Masoume, Pournajaf Abazar, Mirkalantari Shiva, Talebi Malihe, Irajian Gholamreza
Dept of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Dept of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Iran J Pathol. 2015 Summer;10(3):199-205.
The production of carbapenemases especially Klebsiella pneumoniae carbapenemase (KPC) is the most important mechanism of enzymatic resistance in isolated Enterobacteriaceae such as K. pneumoniae . The purpose of this study was detected of the carbapenemase producer K. pneumoniae strains with phenotypic and genotypic methods.
Out of 800 strains, 270 K. pneumoniae strains (33.7%), were obtained. Antibiotic susceptibility test was performed by disk diffusion method in accordance with CLSI guidelines. Carbapenem resistant strains were identified by the Modified Hodge Test based on CLSI instruction and PCR for surveying the presence of bla -KPC gene.
A total 270 K. pneumoniae strains were collected. Antibiotic susceptibility test results showed the highest and lowest resistance was related to piperacillin (60.6%) and carbapenems (14.6%) respectively. 80.5% (33 of 41) isolates were positive by MHT, but all of them (100%) were negative for amplification of the bla -KPC gene in the PCR method.
The MHT was an appropriate method for approving carbapenemase production. Moreover, a laboratory could accept the carbapenemase production with PCR method for the bla-KPC gene, which has the additional profit of validating which KPC is present.
碳青霉烯酶的产生,尤其是肺炎克雷伯菌碳青霉烯酶(KPC),是肺炎克雷伯菌等分离出的肠杆菌科细菌产生酶耐药性的最重要机制。本研究的目的是采用表型和基因型方法检测产碳青霉烯酶的肺炎克雷伯菌菌株。
从800株菌株中获得了270株肺炎克雷伯菌菌株(33.7%)。按照CLSI指南采用纸片扩散法进行药敏试验。根据CLSI说明通过改良Hodge试验鉴定耐碳青霉烯菌株,并采用PCR检测bla-KPC基因的存在情况。
共收集到270株肺炎克雷伯菌菌株。药敏试验结果显示,耐药率最高和最低的分别是哌拉西林(60.6%)和碳青霉烯类(14.6%)。80.5%(41株中的33株)的分离株改良Hodge试验呈阳性,但PCR法检测bla-KPC基因扩增均为阴性(100%)。
改良Hodge试验是确认碳青霉烯酶产生的合适方法。此外,实验室可以采用PCR法检测bla-KPC基因来确认碳青霉烯酶的产生,该方法还有助于验证存在哪种KPC。