636. Comparison of Two Methods for Detecting Extended Spectrum beta-Lactamases
Session: Poster Abstract Session: Pharmacokinetics and Adverse Drug Reactions
Friday, October 21, 2011
Room: Poster Hall B1
Background: We detected a large number of extended spectrum beta-lactamases (ESBLs) producing gram-negative rods in our hospital. In order to evaluate the detecting methods for ESBLs , we compared the sensitivity and specificity of Disk Diffusion Screening test and  Double-Disk Synergy test respectively.

Methods: The disk diffusion screening test was performed to detect ESBLs from 126 Enterobacteriaceae strains isolated from the inpatients, while the double disk synergy test was also done. Disk Diffusion Confirmatory method was performed as golden standard.

Results:  95 suspected ESBLs-producing strains were identified by disk diffusion screening test; 78 strains producing ESBLs were detected by two-disc synergy test; 80 producing ESBLs strains were confirmed by disk diffusion confirmatory test. Compared with the reference method---Disk Diffusion Confirmatory test,  the sensitivity and specificity of the disk diffusion screening test to identify the ESBLs-producing strains are 100% and 75.4% respectively; while for the double-disk synergy test, the sensitivity and specificity are 97.5% and 90.5% respectively.

Conclusion:  The double-disk synergy method is simple, accurate, low cost and is suitable for routine application at different level of hospitals.

Subject Category: A. Antimicrobial agents and Resistance

Qinglian Guo, PH.D., clinical laboratory, Zhongnan hospital of Wuhan university, Wuhan, China


Q. Guo, None

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