Antibiotic resistance Flashcards
Mechanisms of antibiotic resistance
Restrict access of antibiotic - altered membrane permeability.
Get rid of antibiotic - efflux via pumps in cell wall.
Inactivation of antibiotics - produce enzymes which degrade and inactivate antibiotics.
Alter metabolic pathways - use new pathways that bypass antibiotic’s target. Produce more substrate to out-compete competitive inhibitors.
Altered target site - inability for antibiotic to bind, lower affinity.
Co - amoxiclav mechanism
Amoxicillin - kills bacteria bind to PBP blocks transpeptidase , inhibits synthesis of cell wall.
Clavanic acid, binds irreversibly to beta lactamase.
C difficile and antibiotics
Broad spectrum antibiotics, like co - amoxiclav. Wipe out gut flora, c diff can now flourish and proliferate causing symptoms.
Spread of antibiotic resistant genes
Transformation - uptake of extracellular DNA
Conjugation - pilus mediated DNA transfer
Transduction - phage mediated DNA transfer.
Sources of antibiotic genes
plasmids - horizontal gene transfer
transposons - integrate plasmid into chromosomal DNA
Addressing resistance
tighter controls - restriction of ABs for serious infections
temporary withdrawals of certain classes
reduce use of broad spectrum ABs
quicker identification of infections caused by antibiotic strains.
modify existing mechanisms for ABs
Combination therapy