AmpC酶检测方法的探讨

Study on new method for detection of AmpC beta-lactamases

目的建立简便检测肠杆菌科细菌中Amp C酶的方法。方法分别采用双纸片确证法和多剂量协同法检测35株大肠埃希菌和肺炎克雷伯菌,并用三维试验和Amp C酶酶量直接测定法进行对比,同时检测这些菌产ESBL的情况。结果双纸片确证法检测出12株Amp C酶,不受ESBL的干扰,与直接酶量检测法完全一致,敏感性高于三维试验,多剂量协同法敏感性较差。结论双纸片确证法可作为临床检测AmpC酶的方法。

Objective To establish a convenient method for detection of AmpC beta-lactamases in Enterobacteriaceae lacking high-yield chromosomal AmpC beta-laetamases. Methods Thirty-five nonduplicate isolates of Escherichia coli and Klebsiella pneumonia were collected. The diameters of inhibitory zone of eefoxitin were measured alone or in combination with cloxacillin by standard disc diffusion test. The synergic test was used to detect sensitivity of cefoxitin cooperating with cloxacillin. The M3D assay was used as the reference method, The amount of AmpC beta-lactamases was simultaneously measured for all isolates. Results Among 35 isolates, 12 were confirmed to be AmpC beta-lactamases by measuring the amount. Both the sensitivity and specialty of AmpC beta-lactamases phenotypic confirmatory test were 100%. The sensitivity of synergic tests was lower than that of other tests. Conclusion The established double disc phenotypic confirmatory test was a reliable method for detecting AmpC bcta-lactamases in Enterobacteriaceae lacking high-yield chromosomal AmpC beta-lactamases