Gene Mutations Responsible for Overexpression of AmpC β-Lactamase in Some Clinical Isolates of Enterobacter cloacae

摘要

AmpC regulatory genes in 21 ceftazidime-resistant clinical isolates of Enterobacter cloacae (MICs of ≥16 μg/ml) were characterized. All isolates exhibited AmpC overproduction due to AmpD mutation. Additionally, we found two AmpR mutants among the isolates. This is the first report of chromosomal ampR mutation in clinical isolates of E. cloacae.