Cloxacillin-potentiated Disc Diffusion Test to Detect AmpC ?-Lactamases in Gram-negative Bacilli Strains / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To develop a suitable and easy method for detecting AmpC ?-lactamases.METHODS The function with different cloxacillin concentrations in cloxacillin-potentiated disc diffusion test was compared and estimated with FOX three-dimensional extract test to show the best concentration of cloxacillin.RESULTS Cefoxitin three-dimesional test indicated that 48 strains were detected out to produce AmpC ?-lactamases among 130 clinical isolates of Gram-negative bacilli strains.when the discs contained 200 ?g cloxacillin the CAZ,CTX,CRO and ATM alone could separately detect 87.5%,87.5%,87.5% and 33.3% highly producing AmpC ?-lactamases strains.When the combination of CTX with CRO,almost 95.8% could be detected out.CONCLUSIONS With the combination of CTX and CRO,the cloxacillin-potentiated disc diffusion test can specifically detect AmpC ?-lactamases and easy to be used in clinical laboratories.