Antibiotics Resistance And Stewardship Flashcards
Antibiotic resistant
The ability of bacteria to resist the effects of an antibiotic to which they were once sensitive
Antimicrobial resistance
The ability of microbes (bacteria and other microorganisms such as viruses,fungi and parasites) to resist the effects of antimicrobial (e.g antibiotic , antiviral or anti fungal) to which they were once sensitive
Antibiotic stewardship
Practices and protocols that ensure that antibiotics are used prudently and appropriately in order to reduce resistance
Susceptibility to infection
Immune suppression
Surgery
Invasive lines
Other disruptions of defences
What factors drive the use of antibiotics between countries over time?
Infection rates
Quality of antibiotic prescriptions
Roughly how many classes of antibiotics?
14 since 1935 and 1968, then 5 more introduced
How might resistance develop?
Inherent resistance
-e.g mycoplasma (no cell wall)- resistance to beta lactams
De novo development of resistance
Transmission of resistance
Acquisition of colonisation by resistance bacteria
Example of De novo development of resistance
RPOB resistance to rifampicin
HIV resistance to RTI
List some antibiotic targets
Inhibition of cell wall synthesis
Ribosomal effects-inhibition of protein synthesis
Alteration of cell membranes
Inhibition of nucleic acid synthesis
Beta-lactams mechanism of action
Inhibits peptidoglycan synthesis- by covalently binding to PBP (penicillin-binding proteins)
=Prevents cross linkage in cell wall
Beta lactams are?
Antibiotics that contain a beta-lactam ring in their chemical structure
Initial use of beta lactams
1940s in gram positive bacteria
Resistant mechanism of beta -lactams
Change of PBP structure
Porin loss
Pumps
Does not cross membranes
Examples of antibiotics that inhibit cell wall synthesis
Beta lactams
Glycopeptides
Glycopeptides mechanism of action
Peptidoglycan cross linkage in cell wall disrupted
Disrupts peptidoglycan synthesis
Initial use of Glycopeptides
Initial use in 1960s in gram positive organism- no effect on gram negative
Resistance developed
Examples of class that inhibit protein synthesis - 30S ribosome subunit
Aminoglycosides
Tetracyclines
Quinolones mechanism of action
Inhibition of nucleic acid synthesis by:
Interrupts DNA gyrase and topoisomerases required for supercoiling of DNA; bind to alpha subunit
(No uncoiling of DNA)
Resistant mechanism of quinolones
Target changes
quinolones use before:
Use in 70s and 80s- broad spectrum antibiotics
Rifamycins mechanism of action
Used mainly in TB
Inhibits RNA polymerase B by binding so = inhibition of RNA synthesis
Resistant mechanism of Rifamycins
Target changes
Decreased uptake
Class examples that inhibit protein synthesis - 50 s ribosome subunit
Chloramphenicol
Macrolides + Lincomycins- both reversibly bind to 50S ribosome, MLS, block peptide elongation
Examples of Glycopeptides
Vancomycin, teicoplanin
