ESBL: Extended-Spectrum Beta-Lactamase
- Organisms that have a beta-lactamase encoded on a plasmid, allowing for resistance to beta-lactam antibiotics, including extended-spectrum cephalosporins (such as 3rd generation cefotaxime, ceftriaxone, and ceftazidime), and aztreonam. Cefepime has suboptimal efficacy against these organisms
- NOT resistant to carbapenems (so use these to treat if organism is identified to be ESBL-positive)
- Organisms include:
- E. coli
- Pseudomonas aeruginosa
- Klebsiella pneumoniae
- Klebsiella oxytoca
- Proteus mirabilis
- Salmonella enterica
- Neisseria gonorrhoeae
- Haemophilus influenzae
AmpC-Inducible Beta-lactamase
- Organisms that have an inducible beta-lactamase encoded (as the AmpC gene) in their chromosome, allowing for resistance to beta-lactam antibiotics, including extended-spectrum cephalosporins (such as 3rd generation cefotaxime, ceftriaxone, and ceftazidime), and aztreonam
- NOT resistant to fourth-generation cephalosporins or carbapenems (so use these to treat)
- Formerly: SPACE/SPICE used as a mnemonic to remember these organisms
- Serratia
- Pseudomonas aeruginosa
- Acinetobacter
- Indole-positive proteus (i.e. Proteus vulgaris)
- Citrobacter
- Enterobacter
- Now also identified are Hafnia sp. and Providencia sp.
Carbapenemases
- Several different organisms may potentially contain plasmids with carbapenemases, but the most notable is the KPC (Klebsiella pneumoniae carbapenemase) enzyme of the K. pneumoniae species.
- Treatment is based off susceptibility testing
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