Β-lactamases: Difference between revisions
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Β-lactamases
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*** Most common ESBL in Gram-negative bacteria |
*** Most common ESBL in Gram-negative bacteria |
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*** Resistance to 2nd and 3rd generation cephalosporins |
*** Resistance to 2nd and 3rd generation cephalosporins |
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*** Examples include penicillinase, TEM-1 (common in GNBs), CTX-M, ''K. pneumoniae'' carbapenemase (KPC) family |
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*** Common in ''[[E. coli]]'', ''[[Klebsiella]]'', and ''[[Proteus]]'' spp. |
*** Common in ''[[E. coli]]'', ''[[Klebsiella]]'', and ''[[Proteus]]'' spp. |
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*** Examples include: |
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**** Penicillinases: TEM-1 (common in GNBs), SHV-1 |
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**** ESBLs: CTX-M, TEM-3 |
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**** Carbapenemases: ''K. pneumoniae'' carbapenemase (KPC) |
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** '''Class C''': not inhibited by clavulanic acid or EDTA, resistant to cefoxitin, inhibited by clox in vitro |
** '''Class C''': not inhibited by clavulanic acid or EDTA, resistant to cefoxitin, inhibited by clox in vitro |
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*** AmpC = chromosomal |
*** AmpC = chromosomal |
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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 ''[[Acinetobacter]]'' |
*** Common in ''[[Acinetobacter]]'' |
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*** Difficult to detect with routine screening |
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*** Examples include: |
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**** ESBLs: OXA-11 |
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**** Carbapenemases: OXA-23, OXA-48 |
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* '''Class B''': metallo-β-lactamase, inhibited by EDTA, not inhibited by clavulanic acid |
* '''Class B''': metallo-β-lactamase, inhibited by EDTA, not inhibited by clavulanic acid |
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** Examples include |
** Examples include: |
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*** Carbapenemases: |
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**** New Delhi metallo-beta-lactamase (NDM-1) |
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**** IMP |
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*** NDM |
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== Management == |
== Management == |
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Revision as of 00:29, 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 Acinetobacter
- 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.
