Β-lactam resistance: Difference between revisions

Revision as of 08:13, 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

@@ Line 1: / Line 1: @@
-== Mechanisms ==
+==Mechanisms==
-* ß-lactamase production: enzymatic breakdown of beta lactam antibiotic
+*ß-lactamase production: enzymatic breakdown of beta lactam antibiotic
-* Penicillin binding protein mutations (e.g. MRSA)
+*Penicillin binding protein mutations (e.g. MRSA)
-* Efflux pump mutations
+*Efflux pump mutations
-* Porin channel mutations that reduce antibiotic influx
+*Porin channel mutations that reduce antibiotic influx
-== Ambler Classification of ß-lactamases ==
+== 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
+*Based on amino acid sequences rather than function
-== Specific ß-lactamases ==
+*Classes A, C, and D are serine ß-lactamases
-=== NDM-1 ===
+*'''Class A:''' original active-site serine ß-lactamases
-* Broad-spectrum metallo-beta-lactamase and carbapenemase
+*'''Class B:''' original metallo-ß-lactamases
-* Can be treated empirically with [[ceftazidime-avibactam]] and [[aztreonam]] +/- [[colistin]]
+*'''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]]
 [[Category:Antibiotics]]