Β-lactam resistance: Difference between revisions
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Β-lactam resistance
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==Mechanisms== |
==Mechanisms== |
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*Porin channel mutations that reduce antibiotic influx |
*Porin channel mutations that reduce antibiotic influx |
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+ | ==β-lactamases== |
===Ambler Classification of ß-lactamases=== |
===Ambler Classification of ß-lactamases=== |
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*Can be treated empirically with [[ceftazidime-avibactam]] and [[aztreonam]] +/- [[colistin]] |
*Can be treated empirically with [[ceftazidime-avibactam]] and [[aztreonam]] +/- [[colistin]] |
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+ | ==Efflux Pumps== |
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+ | *Major cause of resistance in [[Pseudomonas aeruginosa]] and similar species |
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+ | *e.g. MexAB-OprM, which confers broad antimicrobial resistance including cephalosporins and some carbapanems |
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+ | ==Porin Loss== |
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+ | *Most common cause of carbapenem resistance in [[Pseudomonas aeruginosa]] |
[[Category:Antibiotics]] |
[[Category:Antibiotics]] |
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Revision as of 08:14, 2 August 2020
Mechanisms
- ß-lactamase production: enzymatic breakdown of beta lactam antibiotic
- Penicillin binding protein mutations (e.g. MRSA)
- Efflux pump mutations
- Porin channel mutations that reduce antibiotic influx
β-lactamases
Ambler Classification of ß-lactamases
- Based on amino acid sequences rather than function
- Classes A, C, and D are serine ß-lactamases
- Class A: original active-site serine ß-lactamases
- Class B: original metallo-ß-lactamases
- Class C: AmpC ß-lactamases
- Class D: OXA ß-lactamases
Specific ß-lactamases
NDM-1
- Broad-spectrum metallo-beta-lactamase and carbapenemase
- Can be treated empirically with ceftazidime-avibactam and aztreonam +/- colistin
Efflux Pumps
- Major cause of resistance in Pseudomonas aeruginosa and similar species
- e.g. MexAB-OprM, which confers broad antimicrobial resistance including cephalosporins and some carbapanems
Porin Loss
- Most common cause of carbapenem resistance in Pseudomonas aeruginosa
