AmpC - Organisms that produce AmpC beta-lactamase

Intrinsic resistance to ampicillin, co-amoxiclav and lower generation cephalosporins. With exposure to beta-lactams, induction or de-repression can occur and confer resistance to third generation cephalosporins

Usually susceptible to carbapenems and aminoglycosides

Using non-carbapenem beta-lactams (i.e. Piperacillin/tazobactam) when reported as susceptible is reasonable for SIMPLE infections requiring SHORT duration.