Bacteria I Flashcards
What is the definition of antibiotic?
Natural substance produced by one MO that can kill another
What are the mechanisms of antibacterial action?
Substrate analogues
Steric hindrance
Enzyme inactivation
Disruption or subversion
When might prophylaxis be used?
Ahead of invasive surgery
For decolonisation
To prevent recurrent infections
What methods are used for diagnostics of bacterial infection?
MALDI-ToF
Staining properties
Immunological techniques
How do you see if a bacteria is sensitive to a drug?
Disk diffusion assay
E-test
Broth or agar dilution
What are pharmacokinetics?
What the body does to a drug
What are the pharmodynamic considerations?
Concentration dependent and time dependent
What are the pharmacokinetic considerations?
Concentration of in vivo efficacy is concentration at the site of the action
What drugs have good & bad availability in the CSF?
Beta lactams - good
Amino glycosides and vancomycin - poor
What drugs have good and poor bioavailability in urine?
Trimethoprim and beta lactams - good
MLS antibiotics - poor
What is synergism?
Activity of two antibiotics is better than the sum of each by them self
E.g. Beta lactams and amino glycoside
What is the antagonism?
One agent diminished the activity of another
What is indifference?
Activity unaffected by the addition of another agent
What is clostridium difficile?
Antibiotic associated diarrhoea
Occasionally constituent of the normal intestinal flora
Assumed caused by abolition of colonisation resistance
E.g. Cephalosporins, ciprofloxacin & clindamycin
What does natural flora do?
Provide colonisation resistance
Major source of disease
Can contaminate species
