Antimicrobial Summarizing Statements Flashcards
The three main factors affecting absorption of anitmicrobial drugs are:?
lipid solubility
acid stability
chelation with metal ions such as calcium, magnesium or iron
What is the MIC?
minimum inhibitory concentration is the lowest concentration of that drug that will prevent visible replication of an inoculum of 10^5 in a standardized in vitro test
What is the MBC?
minimum bactericidal concentration is the lowest concentration of the drug that will outright kill 99.9% of the inoculum in that same test
Binding of antimicrobial drugs to proteins such as albumin results in 3 findings/characteristics.
reduces in vivo drug activity
decreases tissue distribution
slows elimination of the drug by glomerular filtration
Why is penciling G particularly useful for strep and syphillus.
both are exquisitely susceptile to penicillin and the benathine salt of penicillin G greatly increases persistence of the drug in circulation
What is the added benefit of the aminopenicilins?
original penicillin is acid labil and not well absorbed from the gut, adding an amino grow causes it to be better absorbed and retain excellent activity of natural penicillins and better coverage of H. influenza, E. coli and proteus
Describe the niche of semi-synthetic penicillins?
methicillin susceptible Staph
What is the extended coverage of extended spectrum penicillins (piperacillin, ticarcillin).
includes good activity against variety of Gram negative, including Pseudomonas and are most often used in combination with a beta-lactamase inhibitor (i.e. amoxicillin/clavulanate and piperacillin/tazobactam)
combo is also more likely to produce diarrhea
Describe the major use for each of the generations of cephalosporins.
1st: gram positive, few gram negatives
2nd: better Gram neg coverage, decreased S. aureus
(*cefoxitin) has good anaerobe coverage
3rd excellent against strep, ceftazidime has Pseudamonas coverage
4th: cefepime: excellent strep, S. aureus and Psuedomonas
5th: ceftaroline: activity against MRSA, MRSE
What is the advantages of carbapenems
extensive activity against S.aureus, Streptocooci, Gram neg rods (including Pseduomonas- except Ertapenem) and anaerobes
should be reserved for resistant GNR or complicated polymicrobial infections
Name the class and activity of aztreonam.
axtreonam- good activity only against Gram negative rods, including Pseudomonas (can be used in with those allergic to beta lactams)
What are the strong points of vancomycin? What class is it?
glycopeptide that has activity of most gram positive, MRSA, MRSE, most enterocci and anaerobic gram positive bacteria as well; most enterococci except VRE
oral is great for C. difficult
What class of drug is daptomycin and what activity does it have?
cyclic lipopeptide (bactericidal) Gram positive and VRE, MRSE, MRSA
CANNOT be used against pneumonia
