Antimicrobials - General stuff and non-classified drugs Flashcards
Are nucleic acid synthesis inhibitors -static or -cidal? Give two examples
-cidal; fluoroquinolones and rifampin
What are 3 drug groups that inhibit folic acid synthesis?
Sulfonamides, trimethoprim, pyrimethamine
What circumstance would you generally prefer a bacteriocidal drug over a -static drug?
in immunosuppressed patients
What is the difference b/w synergism and additive effects of drugs?
additive: 1 + 1 = 2
synergism: 1 + 1 > 2
How do penicillin and aminoglycosides act synergistically?
penicillins make a hole in the cell wall, then aminoglycosides have better access for their effects
Why are penicillin and tetracycline antagonists?
Adding a -static drug generally prevents -cidal drugs from working because most -cidal drugs require cells to be active to work
What is the only protein synthesis inhibitor drug that is bacteriocidal?
aminoglycosides
What is the ultimate action of folic acid synthesis inhibitors?
Inhibit production of thiamine (also adenine and guanine) required for DNA/RNA synthesis
What is the mechanism of resistance against aminoglycosides?
Enzymatic inactivation (transfer of acetyl, phosphorylyl, or adenylyl groups)
What are the 2 mechanisms of resistance against macrolides?
- methyltransferases that alter 50S drug binding sites
2. active transport out of cells
What is the mechanism of resistance against tetracyclines?
active transport out of cells
What is the mechanism of action of polymyxin?
binds to phospholipids (LPS) in gram negative bacteria → disrupt cell membrane
What is amikacin?
an aminoglycoside
What is the mechanism of resistance against aminoglycosides, and what bug has an addition mechanism?
plasmin-endcoded aminoglycoside-modifying enzymes; pseudomonas has a mechanism to decrease entry into the bacterium
