Β-lactam resistance: Difference between revisions
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Β-lactam resistance
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| + | {{DISPLAYTITLE: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=== |
| − | + | *Also see [[Β-lactamases]] |
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| + | ====Ambler Classification of ß-lactamases==== |
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*Based on amino acid sequences rather than function |
*Based on amino acid sequences rather than function |
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| − | *Classes A, C, and D are serine ß-lactamases |
+ | *Classes A, C, and D are serine ß-lactamases, while class B are metallo-β-lactamases |
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| − | *'''Class A:''' original active-site serine ß-lactamases |
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| + | {| class="wikitable" |
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| − | *'''Class B:''' original metallo-ß-lactamases |
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| + | !Class |
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| − | *'''Class C:''' AmpC ß-lactamases |
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| + | !Binding Site |
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| − | *'''Class D:''' OXA ß-lactamases |
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| + | !Examples |
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| + | !Inhibitors |
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| + | |- |
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| + | |A |
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| + | |serine |
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| + | |TEM, SHV, KPC, CTX-M, GES |
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| + | |avibactam, vaborbactam, relebactam |
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| + | |- |
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| + | |B |
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| + | |metallo |
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| + | |VIM, NDM, IMP |
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| + | | |
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| + | |- |
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| + | |C |
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| + | |serine |
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| + | |AmpC, P99 |
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| + | |avibactam, vaborbactam, relebactam |
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| + | |- |
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| + | |D |
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| + | |serine |
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| + | |OXA (oxacillinase) enzymes |
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| + | |avibactam (OXA-48) |
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| + | |} |
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| + | ====Specific ß-lactamases==== |
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| + | *TEM-1: most common β-lactamase in Gram-negative bacteria |
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| + | *KPC: most common carbapenemase |
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| + | *OXA-48: most common carbapenemase in [[Acinetobacter]] |
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| − | === |
+ | ===Efflux Pumps=== |
| − | ====NDM-1==== |
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| − | *Can be treated empirically with [[ceftazidime-avibactam]] and [[aztreonam]] +/- [[colistin]] |
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| − | == |
+ | ===Porin Loss=== |
| − | * |
+ | *Most common cause of carbapenem resistance in [[Pseudomonas aeruginosa]] |
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| − | == |
+ | == Management == |
| + | * See also [[Carbapenem-resistant organisms]] |
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[[Category:Antibiotics]] |
[[Category:Antibiotics]] |
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Latest revision as of 12:10, 2 April 2022
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
- Also see β-lactamases
Ambler Classification of ß-lactamases
- Based on amino acid sequences rather than function
- Classes A, C, and D are serine ß-lactamases, while class B are metallo-β-lactamases
| Class | Binding Site | Examples | Inhibitors |
|---|---|---|---|
| A | serine | TEM, SHV, KPC, CTX-M, GES | avibactam, vaborbactam, relebactam |
| B | metallo | VIM, NDM, IMP | |
| C | serine | AmpC, P99 | avibactam, vaborbactam, relebactam |
| D | serine | OXA (oxacillinase) enzymes | avibactam (OXA-48) |
Specific ß-lactamases
- TEM-1: most common β-lactamase in Gram-negative bacteria
- KPC: most common carbapenemase
- NDM-1: broad-spectrum metallo-β-lactamase and carbapenemase
- OXA-48: most common carbapenemase in Acinetobacter
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
Management
- See also Carbapenem-resistant organisms
