Antibacterial Agents Flashcards
(98 cards)
Penicillins used in combination with tetracyclines produce additive or antagonistic effects?
antagonistic effects
Which antimicrobial agents act through inhibition of bacterial cell-wall synthesis?
penicillins, cephalosporins, imipenem/ meropenem, aztreonam, vancomycin
Which antimicrobial agents inhibit bacterial protein synthesis?
aminoglycosides, chloramphenicol, macrolides, tetracyclines, streptogramins, linezolid
What antimicrobials act through the inhibition of nucleic acid synthesis?
fluoroquinolone, rifampin
What antimicrobials act through inhibition of folic acid synthesis?
sulfonamides, trimethoprim, pyrimethamine
Primary mechanism of resistance for pens and cephalosporins?
production of beta-lactamases, which cleave the beta-lactam ring structure; change in penicillin-binding proteins; change in porins
Primary mechanisms of resistance to aminoglycosides?
formation of enzymes that inactivate drugs
Primary mechanism of resistance to macrolides?
formation of methyltransferases that alter drug binding sites of 50S ribosomal subunit, and active transport out of cells.
Primary mechanism of resistance to tetracycline drugs?
increased activity of transport systems that “pump” drugs out of the cell
Primary mechanism of resistance to sulfonamide drugs?
change in sensitivity to inhibition of target enzyme;
increased formation of PABA;
use of exogenous folic acid
What are the primary mechanisms of resistance in evading fluoroquinolone action?
change in sensitivity to inhibition of target enzymes;
increased acitivity of transport systems that promote drug efflux
What are primary mechanisms of microbials when trying to confer resistance in response to treatment with chloramphenicol?
formation of inactivating acetyltransferases
PBP stands for what?
penicillin binding proteins
Penicillin MOA
pens interact with cytoplasmic membrane binding proteins PBPs to inhibit transpeptidation involved in cross-linking the final steps in cell-wall synthesis
What are the drugs considered antistaph pens?
nafcillin
oxacillin
methicillin
Are antistaph pens beta lactamase sensitive or resistant?
resistant
What spectrum of organisms are antistaph pens effective against?
very narrow: staphylococci (not MRSA)
Name the natural Pens and what organisms the are useful against?
Pen G and Pen V
Narrow spectrum:
streptococci, pneumococci, treponema
Are natural pens beta lactamase resistant or sensitive?
beta lactam sensitive
Name some aminopenicillin drugs, their spectrum and organisms they are useful against?
Amoxicillin
Ampicillin
Broad spectrum
Gram (+) cocci, Listeria, E. coli, Borrelia, H. pylori
Are aminopenicillins beta lactase sensitive or resistant?
sensitive
What is the spectrum of action for antipseudomonal penicillins?
very broad
gram (+) cocci, gram (-) rods, pseudomonas
Are antipseudomonal pens beta lactamase sensitive or resistant?
sensitive
Which drugs act by enhancing the activity of pens because they inhibit betalactamase?
clavulanic acid, sulbactam