Β-lactamases: Difference between revisions
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Β-lactamases
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*** Common in ''[[Citrobacter]]'', ''[[Serratia]]'', and ''[[Enterobacter]]'' |
*** Common in ''[[Citrobacter]]'', ''[[Serratia]]'', and ''[[Enterobacter]]'' |
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** '''Class D''': not inhibited by EDTA, variably inhibited by clavulanic acid; hard to identify |
** '''Class D''': not inhibited by EDTA, variably inhibited by clavulanic acid; hard to identify |
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*** Common in ''[[ |
*** Common in ''[[Pseudomonas]]'' |
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*** Difficult to detect with routine screening |
*** Difficult to detect with routine screening |
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*** Examples include: |
*** Examples include: |
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Revision as of 00:39, 2 February 2020
Definition
- Bacteria containing a plasmid that codes for an extended-spectrum beta-lactamase (ESBL)
- Most common with Escherichia coli and Klebsiella
Classification
- Classes A, B, and C: serine β-lactamases
- Class A: inhibited by clavulanic acid or tazobactam
- Constitutively expressed plasmid
- Most common ESBL in Gram-negative bacteria
- Resistance to 2nd and 3rd generation cephalosporins
- Common in E. coli, Klebsiella, and Proteus spp.
- Examples include:
- Penicillinases: TEM-1 (common in GNBs), SHV-1
- ESBLs: CTX-M, TEM-3
- Carbapenemases: K. pneumoniae carbapenemase (KPC)
- Class C: not inhibited by clavulanic acid or EDTA, resistant to cefoxitin, inhibited by clox in vitro
- AmpC = chromosomal
- Often an inducible AmpC gene present in the genome
- Common in Citrobacter, Serratia, and Enterobacter
- Class D: not inhibited by EDTA, variably inhibited by clavulanic acid; hard to identify
- Common in Pseudomonas
- Difficult to detect with routine screening
- Examples include:
- ESBLs: OXA-11
- Carbapenemases: OXA-23, OXA-48
- Class A: inhibited by clavulanic acid or tazobactam
- Class B: metallo-β-lactamase, inhibited by EDTA, not inhibited by clavulanic acid
- Examples include:
- Carbapenemases:
- New Delhi metallo-beta-lactamase (NDM-1)
- IMP
- NDM
- Carbapenemases:
- Examples include:
Management
- Antibiotic therapy tailored to the resistance pattern
- Carbapenems, aminoglycosides, fluoroquinolones, and Septra typically work well
References
- ^ R. Cantón, M.I. Morosini, O. Martin, S. de la Maza, E. Gomez G. de la Pedrosa. IRT and CMT β-lactamases and inhibitor resistance. Clinical Microbiology and Infection. 2008;14:53-62. doi:10.1111/j.1469-0691.2007.01849.x.
