SPICE organisms

Definition

• Gram-negative bacteria with inducible or derepressable beta-lactamases, primarily chromosomal AmpC

Organisms

• Serratia species
• Providencia
• Indole-positive Proteus species (e.g. Proteus vulgaris, but not Proteus mirabilis)
• Citrobacter species
  • C. koseri does not have an AmpC
• Enterobacter cloacae

Also:

• Hafnia alvei
• Acinetobacter, though not inducible or AmpC (merely very resistant_
• Morganella morganii
• Cronobacter
• Edwardsiella

Treatment

• Not penicillins or cephalosporins, as resistance will develop within a few days
• Carbapenems still work, as do aminoglycosides

Further Reading

• Jones R, Baquero F, Privitera G, Inoue M, Widermann B. Inducible β-lactamase-mediated resistance to third-generation cephalosporins. Clin Microbio Infect. 1997;3(1):S7-S20.
• https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciz173/5369903