Antimicrobial resistance Flashcards
General mechanisms of gaining resistance
Loss of genetic material
Gain of genetic material (e.g. plasmids or integrons)
Mutation of genetic material
General mechanisms of antibiotic resistance
- enzymatic degradation of AB
- Altered target
- Decreased uptake/ Increased secretion
- Bypass pathway
Examples of enzymatic degration of AB
Beta-lactamases (many kinds, for all types of beta-lactams)
Aminoglycoside inactivating enzyme
What does SPACE mean?
S: Serratia P: Pseudomonas A: Acinetobacter C: Citrobacter E: enterobacter
Are AmpC producers
Examples of altered AB targets
altered PCP Ribosomal binding site alteration DNA gyrase alteration Change in aa on peptidoglycan chain Dihydroopterate synthetase alteration Dihydrofolate reductase alteration
Examples of bypass pathways
Using exogenous thymidine to make DNA instead of folate
Examples decreased uptake/ increased secretion of Ab
mefA pumps macrolides out
change in porin that allows B-lactam in
Mechanisms of resistance to B-lactams
1) beta-lactamases (ESBL is bad!)
2) Altered PBP
3) Porin mutation to increase efflux
Mechanisms of resistance to macrolides
1) change in ribosomal binding site
2) efflux pump (mefA)
Mechanisms of resistance to tetracyclines
Change in ribosomal binding site
Mechanisms of resistance to lincosamide
change in ribosomal binding site
Mechanisms of resistance to aminoglycosides
1) change in ribosomal binding site
2) inactivating enzymes
Mechanisms of resistance to fluoroquinolones
Point mutation in DNA gyrase/topoisomerase
Efflux pumps
Mechanisms of resistance to anti-folates
change in enzyme target site
bypass pathway using exogenous thymidine
Examples of superbugs
- MRSA
- VRSA
- VRE
- ESBL (bugs carrying ESBL..)
- CRE (carbapenem resistant enterobacteriaceae) with NDM (New Delhi metallo beta-lactamase) or KPC (Klebsiella pneumoniae cabapenemase)
