AmpC - Organisms that produce AmpC beta-lactamase


Standard Precautions
Standard Precautions

General Information

Pathogen information

Gram negative organisms historically referred to as "SPICEM" organisms:
Serratia spp.
Providencia spp.
Citrobacter freundii (not applicable to other Citrobacter)
Enterobacter spp.
Morganella morganii

Primary therapeutic concern with AmpC is induction/de-repression of beta-lactamase enzyme with exposure to beta-lactams.

This can confer resistance to third generation cephalosporins and some beta-lactam/beta-lactamase inhibitors, leading to treatment failure with these antimicrobials.


Most AmpC organisms are healthcare-associated. They are Enterobacteriaceae that are part of the GI flora.

Associated syndromes

Cause syndromes by the organism that possesses AmpC (see individual organism)

Additional Information

ESBLs vs. ampC: Most ESBLs are plasmid-encoded beta-lactamases, whereas ampCs are usually inducible and chromosomal beta-lactamases.