AmpC - Organisms that produce AmpC beta-lactamase

Intrinsic resistance to ampicillin/amoxicillin, cefazolin, and oral cephalosporins. With exposure to beta-lactams, induction or de-repression can occur and confer resistance to third generation cephalosporins.

Susceptible to carbapenems

May be susceptible to fluoroquinolones, TMP-SMX, and aminoglycosides which may be appropriate targeted therapy options.

Usually susceptible to aztreonam.