AmpC - Organisms that produce AmpC beta-lactamase
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
Cause syndromes by the organism that possesses AmpC (see individual organism)
May require contact precautions if highly resistant.
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