SELECTIVE TOXICITY Flashcards
How does abx have the ability to kill or suppress microbial pathogens w/o harming host??
selective toxicity
What are 3 examples of selective toxicity?
- Disruption of bacterial cell wall
- Inhibit enzyme unique to bacteria
- inhibit bacterial protein synthesis
Narrow spectrum abx kills what type of bacteria?
G+ cocci and G+ bacilli
G- aerobes
Mycobacterium tuberculosis
Abx that:
INHIBITS CELL WALL SYNTHESIS
PCN, cephalosporins, imipenem,
Vanco, caspofungin
Broad spectrum abx kills what type of bacteria?
G+ cocci and G- bacilli
abx that:
DISRUPTS CELL MEMBRANE
Amphotericin B, Daptomycin, Itraconazole
BACTERIOSTATIC (halt) inhibitors of protein synthesis
Clindamycin, erythromycin, linezolid, tetracyclines (CELT)
BACTERICIDAL (kills) inhibitors of protein synthesis
Aminoglycosides
Rx that interferes with synthesis OR integrity of bacterial DNA and RNA
Fluoroquinolones, metronidazole, rifampin (FluMeR)
Antimetabolites drugs
Flucytosine, sulfonamides, trimethoprim (FST)
Drug level for minimal inhibitory concentration (MIC)
4-8x
How do microbes become resistant?
- decrease penetration to target site
- alteration of target site
- inactivate drug by bacterial enzyme
Factors to consider when choosing abx
- which bacteria?
- pattern of resistance
- organism susceptibility
- achievable semen, tissue, or body fluid concentration
- allergy
- toxicity
- formulation/ bioavail
- adherence/ convenience
- cost and formulation options
Use of combination abx can result in what?
additive, potentiate or antagonistic effect
What generation of cephalosporin is most commonly used for surgery prophylaxis ?
first gen (cefazolin)
PCN is also known as______.
beta- lactam abx
What is the MOA of PCN?
Disruption of cell wall synthesis by inhibiting transpeptidases and activation of autolysin
The use of trimethoprim/sulfamethoxazole results in what effect?
potentiative
PCN G and V are___ spectrum PCN (penicillinase sensitive)
narrow
PCN G and V are useful for which microbes?
Streptococcus spp., N spp., many anaerobes, spirochetes, and others
Nafcillin, oxacillin, and dicloxacillin are _____ spectrum PCN
narrow; penicillinase resistant
Ampicillin and amoxicillin are ___ spectrum abx
broad spectrum
What microbes do nafcillin, oxacillin, and dicloxacillin kill?
S. aureus
Ampicillin and amoxicillin are effective against which microbes?
H. influenzaue, E. coli, P. mirabilis, enterococci, and N. gonorrhoeae
