Antibiotics & Antimicrobial Stewardship Flashcards
How are antimicrobials classified?
Antibacterial, antifungal, antiviral and antiprotozoal agents
How are antibacterials classified?
Bacteriocidal or bacteriostatic, broad or narrow, mechanism of action, chem structure
What are the ideal features of antimicrobial agents?
Selectively toxic, few adverse effects, reach site of infect, oral/IV, long half-life, no interference with other drugs
What are the mechanisms of antibiotics?
Inhibit cell wall synthesis, interrupt cell wall function, inhibit nucleic acid synthesis, inhibit protein synthesis
Name a class of Abx that inhibits cell wall synthesis
Beta-lactams
Name a of class of Abx that interrupt cell membrane function
Polymixins
Name a class of Abx that inhibit nucleic acid synthesis
Quinolones
Name a class of Abx that inhibit protein synthesis
Tetracyclines, aminoglycosides
How is bacterial cell wall synthesis inhibited by Abx?
PBP blocked by Abx, or Abx blocks binding spot on cell wall for PBP
How is nucleic acid synthesis inhibited by Abx
Quinolones bind topoisomerase/DNA gyrase inhibited DNA replication
Outline how antibiotics stop bacterial protein synthesis
Abx interfere with the 30S + 50S ribosomes
Describe how Abx interfere with cell membrane function
Disrupt structure = lysis
What are the types of antimicrobial resistance
Intrinsic = no target/access for drug,
acquired = new genetic material,
adaptive = MO responds to stress
What are the mechanisms of resistance?
Inactivating enzymes = beta-lactamases,
altered target = change of antigens,
altered uptake = efflux pumps
What mechanisms enable antibiotic resistance to be acquired?
Horizontal gene transfer, vertical gene transfer = mother to daughter
By what methods can horizontal gene transfer take place?
Conjugation = plasmid transfer,
transduction = viral delivery,
transformation = genetic material from dead bacteria
How can the Abx sensitivity of a bacteria be measured?
Disc sensitivity testing,
MIC = minimum inhibitory testing
Name and outline a combination Abx
Co-amoxiclav = amoxicillin + clavulanic acid = acids inhibits lactamases, amox = kills G -ve
What are cephalosporins and how are they classified?
Beta-lactam Abx, 1st 2nd and 3rd generation = new gens have significantly greater G -ve antimicrobial properties
When are penicillin’s used?
Staph, step,
Some activity for G –ve
When are cephalosporins used?
G +ve and –ve, broad spec
When are carbapenems used?
Broad spec, G –ve, safe in penicillin allergy, kills anaerobes
Give an example of a glycopeptide and outline when it is used
Vancomycin = G +ve, requires therapeutic drug monitoring = small therapeutic window, some enterococci are resistant (VRE)
When are tetracyclines used?
E.g. doxycycline: Broad spec, used in penicillin allergy, oral only, chlamydia and some protozoa
