Β-lactam resistance: Difference between revisions

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Β-lactam resistance
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= Beta-lactam resistance =
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{{DISPLAYTITLE:β-lactam resistance}}
   
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== Mechanisms ==
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==Mechanisms==
   
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* ß-lactamase production: enzymatic breakdown of beta lactam antibiotic
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*ß-lactamase production: enzymatic breakdown of beta lactam antibiotic
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* Penicillin binding protein mutations (e.g. MRSA)
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*Penicillin binding protein mutations (e.g. MRSA)
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* Efflux pump mutations
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*Efflux pump mutations
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* Porin channel mutations that reduce antibiotic influx
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*Porin channel mutations that reduce antibiotic influx
   
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== Ambler Classification of ß-lactamases ==
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===β-lactamases===
   
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*Also see [[Β-lactamases]]
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* Based on amino acid sequences rather than function
  
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* Classes A, C, and D are serine ß-lactamases
  
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* Class A: original active-site serine ß-lactamases
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====Ambler Classification of ß-lactamases====
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* Class B: original metallo-ß-lactamases
  
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*Based on amino acid sequences rather than function
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* Class C: AmpC ß-lactamases
  
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* Class D: OXA ß-lactamases
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*Classes A, C, and D are serine ß-lactamases, while class B are metallo-β-lactamases
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{| class="wikitable"
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!Class
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!Binding Site
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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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*NDM-1: broad-spectrum metallo-β-lactamase and carbapenemase
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*OXA-48: most common carbapenemase in [[Acinetobacter]]
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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]]
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== Management ==
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* See also [[Carbapenem-resistant organisms]]
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[[Category:Antibiotics]]

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

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

Management

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