碳青霉烯耐药克雷伯菌耐药机制研究

Resistance mechanism of carbapenem resistant Klebsiella

目的:探讨碳青霉烯耐药克雷伯菌的耐药机制。方法:临床微生物实验室分离到36株碳青霉烯耐药克雷伯菌,改良Hodge试验、EDTA协同试验及PCR法检测碳青霉烯酶耐药基因,PCR法检测ESBLs及Ampc酶耐药基因,PCR、实时荧光定量PCR(RT-PCR)法检测外膜蛋白基因Ompk35及Ompk36存在及表达情况。结果:9株改良Hodge试验阳性,EDTA协同试验均阴性,碳青霉烯酶耐药基因均阴性;36株碳青霉烯耐药克雷伯菌至少存在1种β内酰胺酶耐药基因;外膜蛋白基因无缺失,33株存在外膜蛋白表达量下降。结论:分离的碳青霉烯耐药克雷伯菌耐药机制可能为ESBLs及Ampc酶表达合并外膜蛋白表达下降。

Objective： To investigate the mechanism of carbapenem resistant Klebsiella. Methods： Thirty-six carbapenem resistant Klebsiella were collected. Modified Hodge test, EDTA synergy test and PCR were applied to detect genes of ESBLs and Ampc carbapenemases. PCR and RT-PCR test were conducted to detect gene of outer membrane protein Ompk35 and Ompk36 and their expressions. Results： Nine strains were found by modified Hodge test positive. EDTA co-test results were negative. Carbapenemase resistance genes detection results were all negative. Thirty-six strains of carbapenem resistant Klebsiella showed at least one β-lactamase resistance gene. There was no deletion of membrane protein gene, and 33 cases showed decreased expression of outer membrane protein.Conclusion： The probable drug-resistant mechanism of the Klebsiella isolated is the combined expression of the ESBLs and Ampc enzyme and may decrease expression of out membrane protein.