Gram negative organisms, usually "SPICEM" (see additional information), that have a chromosomal beta-lactamase.
Most AmpC organisms are nosocomially encountered, are GI flora and are part of the Enterobacteriaceae family.
Syndromes caused by the organism that possesses AmpC (see individual organism).
ESBLs vs. AmpC: Most ESBLs are plasmid-encoded, whereas AmpCs are usually inducible and chromosomal.
In the lab, AmpCs test resistant to cefoxitin and cefotetan. They test susceptible to aztreonam.
SPICEM stands for Serratia, Pseudomonas and Providencia, (Indole positive) Proteus vulgaris, Citrobacter, Enterobacter, and Morganella