- Beta lactams are strong inducers generally except
– 3rd and 4th gen cephalosporin
– Ticarcillin, piperacillin
- beta lactamase inhibitors are also strong inducers (clavulanic acid the strongest).
- Carbapenems are strong inducers but are stable. So does cefepime (carbapenem > cefepime)
- Other strong inducers are generally labile. most of the weak inducers are labile.
Weak and labile inducers (= not stable, easily hydrolyzed) will lead to selection of derepressed AmpC strains.
ESBL producing organisms: SPICE-M
- Indole positive proteus**
Inducible ampC producing organisms (ESPCM) – normally present in low levels (repressed), so inducible isnt so significant, but derepressed strains are !
- Enterobacter spp (E.aerogenes, cloacae)
- Serratia spp
- Morganella morganii
- Providencia rettgeri
- Citrobacter freundii
Basal = not inducible and expressed at low levels: E.coli, shigellae
- ESBL: carbapenems are first line. BL/BLI maybe options if low MIC
– Wild inducible type: BL/BLI, normally not clinically significant
– Derepressed type: carbapenems are first line, but cefepime is okay if susceptible and source control is done.