Abx Flashcards
Prophylaxis
treating pts who are not yet infected or have developed the dz. (prevention of infection)
empiric therapy
drug/tx based solely on experience & relevant, clinical observational information including resistance patterns (unknown specifics about dz but you suspect a certain dz.)
definitive therapy
tx that is generally accepted as the specific cure of a disease (specific culture = target drug for organism)
normal flora
organisms that live symbiotically on/within host - rarely cause dz.
colonization
the process of a newly introduced microorganism that wins over normal flora
infection
invasion of the body by a pathogenic microorganism - reproduces and multiples - causes local cell injury, secretion of toxin, or antigen/antibody reaction in the host
superinfection
extreme proliferation of a parasitic organism during abx tx for a different infection (opportunistic)
contamination
infectious organism that is passed (virus) for one infected person to an object (and maybe on to another person)
bactericidal
substance that kills bacteria
bacteriostatic
agent that prevents growth of bacteria (bacteria cannot replicate)
MIC - minimum inhibitory concentration
the lowest concentration of Abx that INHIBITS bacterial growth
- effective antimicrobial tx needs to be greater than the MIC
MBC - minimum bactericidal concentration
minimum concentration of Abx that KILLS the bacteria of interest
- 99.9% decline in colony count at this concentration
Susceptible
An organism is called “susceptible” to drug when the infection czed by it is likely to respond to treatment w/ this drug, at the recommended dosage.
moderately susceptible
antibiotic that can be used for treatment at a higher dosage bc of its low toxicity or bc antibiotic is concentrated in the focus of infection (ex- urine
intermediate susceptibility
toxic antibiotic that can’t be used at a higher dosage
Resistant
term implies that organism is not expected to respond to a given drug, irrespective of the dosage & location of infection
Narrow spectrum
acts against a single or limited group of microorganisms (ie-isoniazid)
Extended spectrum
acts against gram Pos & some Gram Neg (ie- ampicillin)
Broad spectrum
ie- tetracycline, chloramphenicol
Bactericidal drugs
are those that kill target organisms, more aggressive & often chosen for critically ill.
Bacteriostatic drugs
inhibit or delay bacterial growth & replication at serum (or urine) levels, limiting spread of infection until body’s immune system can handle attack. (ex: tetracyclines, sulfonamides, & macrolides.
synergistic effect
the combination of two drugs is a GREATER effect than each of the drugs has individually (1+1=3)
additive effect
the combination of two drugs is EQUAL to the combined responses of the individual drugs if they were taken separately (1+1=2)
When to use combination therapy
1) tx before ID of organism is known
2) achieve synergistic effect
3) prevent the emergence of resistant organisms (bacteria becomes resistant to one drug, the other drug will kill it - preventing the emergence of resistant strains)
4) decrease dose-related toxicity - use smaller doses of multiple drugs rather than one large dose of one drug
5) tx polymicrobial infections (gram +/- etc.)
