Abx general Flashcards
Gram Stain
1st identification test run on specimen
identifies pathogen as Gram positive or gram negative and shape as cocci or bacilli
Gram neg=red
gram positive= violet
Infection
isolated organisms are from the specimen and causing the infection
Colonization
isolated organisms are from the specimen, but are NOT causing symptoms
Contamination
isolated organisms came from pt’s skin or the environment
Minimum Inhibitory Concentration (MIC)
lowest antimicrobial concentration that prevents visible growth of organism
Susceptible
can get enough drug into pt to tx infection (MIC<attainable serum levels)
Intermediate
may not be able to get enough drug into pt to tx the infection unless the drug is safe enough to give in high doses, or the drug concentrates exceptionally well at infection site.
Resistant
you cannot get enough drug into the pt to tx the infection (MIC > attainable serum levels)
Time Dependent Killers
killing dependent on the time the organism is in contact with drug. The duration that the drug concentrations are above the MIC is important
Ex: beta-lactams, vancomycin
Concentration dependent killers
dependent on the concentration of the drug that the organism is exposed to- higher the concentration the greater the killing
Ex: fluoroquinolones, aminoglycosides
Synergy
use 2 abx with 2 mechanisms of action and you have increased killing of bacteria
often used with enterococcus endocarditis or bacteremia, sepsis, pseudomonal infections
Post Antibiotic Effect (PAE)
organism growth is supressed for period of time after drug concentration falls below MIC
often can be dosed daily (aminoglycosides)
Intrinsic Resistance
naturally occurring resistance (drug cant penetrate organisms cell wall)
Acquired Resistance
a normally sensitive organism becomes resistant to a drug
Detoxifying Enzymes
can alter abx structure and function
beta-lactamase–> breaks down beta-lactam ring of penicillin abx
