协同法过筛检测金属β内酰胺酶的研究

Study on screening assay of metallo-β-lactamase by antibiotic sensitivity synergic methods

目的 探讨并建立在临床微生物实验室可用于常规过筛检测金属 β内酰胺酶 (BKA)的方法 ,为临床合理选择抗生素提供确切的依据。方法 以EDTA·K2 为酶抑制剂 ,头孢他啶、头孢噻肟、亚胺培南为底物 ,在MH平板上用纸片扩散法进行抗生素协同敏感性检测并与聚合酶链反应(PCR)检测金属BLAblaIMP结果进行比较。结果 金属BLA阳性的菌株在 3种底物纸片中至少有 1种与EDTA·K2 纸片有协同作用 ;在 132株受试菌中PCR检测的金属BLAblaIMP基因阳性菌株 6 3株、协同法阳性 88株 ;两者同时阳性的 6 1株 ,PCR法阳性而协同法阴性 2株 ,PCR法阴性而协同法阳性 2 7株 ,两者均阴性 4 4株。结论 协同法检测革兰阴性杆菌中的金属BLA方法简便、结果可靠、成本低廉 。

Objective To discuss and establish a method for screening of the metallo β lactamase in the clinical microbiology laboratory in order to help choosing antibiotics. Methods The enzyme inhibitor was EDTA.K 2, and the substrate were ceftazidime, cefotaxime. and imipenem. The microbiology sensitivity synergic tests, were processed by KB method in the M H agar. and compared with the PCR results of metallo beta lactamase gene detection. Results The metallo β lactamase producing bacteria, synergize with EDTA K2 disc at least in one of the three kinds of substrate In 132 of imipenem resistance strains, the metallo β lactamase positive strains were detected by this method was 88 and that by PCR was 63, respectively. 61 strains were positive detected by the two methods synchronously, as well as 44 strains were negative, 2 strains were positive detected by PCR assay but negative by this method, and, 27 strains were contrary. Conclusion This method was simple, credible and cheap. It was suitable for screening detection of the metallo β lactamase routinely in the clinical microbiology laboratory.