用头孢西丁三相试验检测大肠埃希菌及肺炎克雷伯菌的质粒AmpC酶

目的：检测质粒介导的持续高产AmpC酶在大肠埃希菌及肺炎克雷伯菌中的携带率，为临床治疗提供指导。方法：采用头孢西丁纸片药敏试验（K-B法）作AmpC酶的初筛试验，头孢西丁三相试验间接法作AmpC酶的确证试验。结果：在检测的86株菌中，有9株菌K-B法初筛结果为阳性。在这9株菌中经头孢西丁三相试验确证有5株产AmpC酶，阳性率为5.8%。其中大肠埃希菌3株，肺炎克雷伯菌2株。结论：头孢西丁K-B法筛选试验结合头孢西丁三相试验可准确检出质粒介导的AmpC酶，可用于临床常规检测。

Detection of plasmid-mediated AmpC expressed in Escherichia coli and Klebsiella pneumoniae by cefoxitin three-dimensional test

Objective: To detect the prevalence rate of the plasmid-mediated AmpC expressed constitutively at high level in Escherichia coli and Klebsiella pneumoniae for providing guideline for clinical therapy. Methods: Cefoxitin susceptibility disk test (K-B method) was used for screening and indirect cefoxitin three-dimensional test was used for the confirming of plasmid-mediated AmpC. Results: Of 86 strains,9 isolates were positive by K-B screening method. Of the 9 positive isolates, 5 (three Escherichia coli, two Klebsiella pneumoniae) were positive by indirect cefoxitin three-dimensional confirming test, with a positive rate of 6.9%. Conclusion:Cefoxitin screening test combinated with indirect three-dimensional test can detect plasmid-mediated AmpC accurately and can be used in clinical routine detection.