耐亚胺培南铜绿假单胞菌oprD2基因与金属酶的检测

Detection of the genes encoding oprD2 and metallo-β-lactamases in imipenem-resistant Pseudomonas aeruginosa

目的研究oprD2基因与金属酶(MBL)在亚胺培南耐药机制中的作用。方法对天津地区3所综合医院临床分离60株亚胺培南耐药的铜绿假单胞菌,以2-巯基乙醇(2-MPA)为酶抑制剂,在MH平皿上用纸片扩散法进行抗生素协同敏感性检测,并用PCR检测MBL基因和oprD2基因。结果60株临床分离的耐亚胺培南铜绿假单胞菌(imipenem-resistant Pseudomonas aeruginosa,IRPA)中,2-MPA方法筛选出15株(25%)MBL阳性;以PCR方法检测,22株(36.4%)oprD2基因阳性,19株(31.7%)产生IMP-1型MBL,未发现VIM-2与IMP-2酶,7株IRPA同时含有IMP-1和oprD2基因。结论IMP-1为天津地区IRPA产MBL的主要类型,也是临床分离铜绿假单胞菌亚胺培南耐药的重要原因之一。

Objective To evaluate the association between presence of oprD2 and metallo-13- lactamases （MBLs） genes and imipenem resistance. Methods The 2-mercaptoethanol （2-MPA） was used as enzyme inhibitor. The synergistic antimicrobial susceptibility testing was done by K-B method with MH agar. The metallo-beta-lactamase genes and OprD2 gene were detected by PCR. Results Of the 60 clinical isolates of imipenem-resistant P. aeruginosa （IRPA）, 15 （25%） were MBL-positive using phenotypie methods, 22 （36.36%） positive for oprD2 gene, 19 （31. 66%） positive for IMP-1 type MBL by PCR. Neither VIM-2 nor IMP-2 type MBL gene was identified among thesestrains. Conclusions IMP-1 is the most prevalent MBL type in Tianjin. The IMP-1-producing isolates are an important contributor to imipenem resistance.