金属β-内酰胺酶最佳酶抑制物的研究

目的探讨临床微生物实验室金属β-内酰胺酶最佳酶抑制物选择,建立一种避免金属酶漏检的方法。方法以Cucl2、Hgcl2、Fecl2、二乙烯三胺五乙酸、乙二胺四乙酸、2-巯基丙酸、巯基乙醇、巯基乙酸与头孢他啶(CAZ)药物纸片增效法测定质控菌株金属酶,从中评估出抑菌最强的酶抑制物与头孢他啶(CAZ)联合检测临床分离的100份耐亚胺培南和(或)头孢他啶铜绿假单胞菌,结果与聚合酶链反应(PCR)检测金属酶基因进行比较。结果增效法检测100份耐亚胺培南和(或)头孢他啶铜绿假单胞菌中有9份金属酶阳性,与PCR检测结果一致,阳性株中3株IMP-1扩增阳性,6株VIM扩增阳性,经基因测序确认为VIM-2型。结论用EDTA、2-巯基丙酸和头孢他啶(CAZ)药物纸片联合检测金属酶,可避免金属酶的漏检,其方法简便,结果可靠,可在基层微生物实验室开展使用。

Study on Optimal Inhibitors of Metallo-beta-lactamase

Objective To explore the optimal inhibitors of metallo-beta-lactamase in clinical microbiology laboratory and to establish a method for avoiding failure in detection of metallo-beta-lactamase.Methods By using Cucl2,Hgcl2,Fecl2,DTPA,EDTA,2-Mercapzopropionic acid,mercaptoethanol,and mercaptoacetic acid as enzyme inhibitor and ceftazidime(CAZ) as the substrate,the potentiated tests of microbial sensitivity were performed by KB method on MH agar.The strongest inhibitor was evaluated in this test,Metallo-beta-lactamase produced by 100 imipene(IMP) and/or ceftazidime(CAZ)-resistant strains of Pseudomonas aeruginosa isolated from clinical specimens were detected by using the strongest inhibitor,and the result was compared with the result of metallo-beta-lactamase gene PCR verification.Results There were 9 strains of bacteria produced metallo-beta-lactamase in the tested 100 strains of Pseudomonas aeruginosa and the results of potentiated tests were consistent with those of PCR.Three were positive in PCR analyses with blaIMP primers,and 6 with blaVIM and were verified by VIM-2 DNA sequencing.Conclusions By using EDTA and 2-MPA, the inhibitor-potentiated disk diffusion test can avoid failing detection of metallo-beta-lactamase,and it is a convenient and creditable test that is fitted with clinical microbiology laboratory use.