View source for Β-lactam resistance

{{DISPLAYTITLE:β-lactam resistance}}

==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="wikitable"
!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]]

[[Category:Antibiotics]]