- 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.
James G. Smirniotopoulos et al. Patterns of Contrast Enhancement in the Brain and Meninges. RadioGraphics 2007; 27:525–551