Evaluation of efficiency of screening extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in hospitals where the bacteria are increasingly prevalent

The disk screening methods for extended-spectrum R-lactamase-producing stra ins were evaluated. The confirmatory work is reduced significantly in setti ngs such as those in this study, by changing the cefpodoxime breakpoint to less than or equal to 20 mm and by not testing cefoxitin-resistant isolates . Cefotaxime and ceftazidime disk screening is reliable, and the laboratory -prepared cefotaxime- and ceftazidime-clavulanic acid disks are stable at - 20 degreesC for 12 weeks.