多重耐药铜绿假单胞菌β内酰胺类抗生素耐药基因和膜孔蛋白基因研究

Prevalence and characterization of β-lactamase genes and porin-encoding gene in multidrug resistant Pseudomonas aeruginosa

目的分析临床分离的20株多重耐药铜绿假单胞菌(MDR-PAE)中的β内酰胺类耐药基因和膜孔蛋白基因的存在状况。方法收集2009年2月至2010年4月南京医科大学第二附属医院住院患者中分离的MDR-PAE20株,采用PCR及序列分析方法对23种β内酰胺类抗生素耐药基因和膜孔蛋白基因进行检测及基因序列分析。结果 20株MDR-PAE菌中检出TEM、PER、DHA、OXA-10群等4种β内酰胺酶基因,阳性率分别为25%、20%、5%、20%,6株细菌检出1种以上β内酰胺酶基因;膜孔蛋白编码基因OprD2均缺失(缺失率为100%)。结论本组20株MDR-PAEβ内酰胺类耐药基因的携带率较低,该菌对亚胺培南耐药与其膜孔蛋白编码基因OprD2缺失有关,而对其他抗菌药物的耐药可能与其外排泵的增强表达有关。

Objective To analyze the prevalence of β-lactamase genes and porin gene in 20 clinical strains of multidrug resistant P.aeruginosa(MDR-PAE).Methods Twenty MDR-PAE strains were isolated from the patients in the Second Affiliated Hospital of Nanjing Medical University during February 2009 and April 2010.A total of 23 β-lactamase genes as well as porin gene were analyzed by PCR and verified by DNA sequencing.Results Of the 20 MDR-PAE strains,TEM,PER,DHA and OXA-10 cluster genes were identified.The prevalence of above genes was 25%,20%,5% and 20%,respectively.Six of the twenty strains carried more than 1 β-lactamase gene.The porin-encoding gene OprD2 was deleted in all the 20 strains.Conclusions The prevalence of β-lactamase genes in this group of MDR-PAE strains is relatively low.The imipenem resistance of P.aeruginosa is associated with the loss of porin gene OprD2.The resistance of P.aeruginosa to other kinds of antimicrobial agents may have to do with the increased expression of efflux pumps.