Basis Of Antimicrobial Chemotherapy Flashcards
What are two key factors for an effective antibiotic?
*clinically effective
*selective toxicity
When are antibiotics required?
*an infection is most likely to cause serious harm if not treated quick
*patient has poor immune response
*prophylaxis
What is empiric therapy?
*therapy given before pathogen is identified and tested for sensitivity to antibiotics
*requires knowledge of - most likely causative organism, drugs and their effectiveness, likelihood of resistance, benefits of therapy vs toxicity
What is the process of choosing the right antibiotic?
*clinical diagnosis
* EMPIRIC THERAPY
*isolation + identification of causative organism
*sensitivity testing of isolated pathogen
*knowledge of PK and PD properties of antibiotics
What are examples of pathogen sensitivity tests?
*agar diffusion test
*E-tests
What are limitations of sensitivity tests?
*experiment uses fixed concentrations
*site of infection
*pharmacodynamics
What are bactericidal antibiotics?
Cause microbial death and lysis at concentrations achieved clinically
What are bacteriostatic antibiotics?
*inhibit further bacterial growth but don’t kill at clinically achieved concentrations
*allows NEUTROPHILS and other host defences to eliminate pathogen
*a ‘budge’
What are examples of antibiotics that have a concentration dependent killing approach?
*metronidazole
*fluoroquinolones
*aminoglycosides
What are examples of antibiotics that have a time dependent killing approach?
*penicillins
*erythromycin
*cephalosporins
*linezolid
What are patient factors that should be considered when choosing an antibiotic?
*age
*allergy history
*previous exposure to antibiotics
*site of infection
*if female- pregnancy, breast feeding, oral contraceptives
What is pseudomembranous colitis?
Overgrowth of C. Diff in bowel causing intestinal disturbances
Antibiotics responsible- Clindamycin, penicillins, cephalosporins
Why would antibiotic combinations be used?
*provide broad spec cover
*provide synergy
*prevent emergence of resistance
*treat mixed infections
What are the four RIGHTS of medicine?
*right THERAPY
*right PATIENT
*right DOSE
*right TIME
