False extended-spectrum {beta}-lactamase phenotype in clinical isolates of Escherichia coli associated with increased expression of OXA-1 or TEM-1 penicillinases and loss of porins.

摘要

OBJECTIVES: Two clinical isolates of Escherichia coli, EC18 and EC21, were non-susceptible (MICs 4-16 mg/L) to cefpirome and cefepime, with marked synergy with clavulanate, yet were susceptible to cefotaxime and ceftazidime (MICs