Laboratory diagnosis of bloodstream infections caused by extended-spectrum 6-lactamase-producing E. coli and Klebsiella species

摘要

Extended-spectrum S-lactamase (ESBL)-producing organisms are resistant to the third-generation cephalbsporiris commonly used as empirical therapy for a wide range of serious infections. It is therefore important for laboratories to offer reliable ESBL detection methods. This study compares two combination disc methods (Oxoid and Mast Diagnostics) containing cepodoxime with and without clavulanate -with Vitek 2 for routine detection of ESBLs in Escherichia coli and Klebsiella spp.isolated from blood cultures. From December 2003 to April 2005, a total of 58 potential ESBLrproducing isolates (resistant to cefotaxime and/or xeftazidime) by BSAC disc susceptibility were tested by the combination discs and Vitek 2. The Advanced Expert System, a feature of Vitek 2, reports possible mechanisms of resistance, based on interpretive reading of MICs.