antibiotic action Flashcards
oxazolidinones
bind 23S rRNA and prevent 70S complex
streptomycin and tobramycin (and gentamycin and amikacin)
bind 30S to distort A site, inhibits protein synthesis
tetracyclines
bind 16S rRNA of 30S to prevent aa- tRNA to A site
rifampin and rifabutin
bind RNA polymerase and prevent transcription
macrolides (erythromycin)
-bind 23 rRNA in 50S to block translocation
-formation 50S subunit
chloramphenicol
bind 50S and inhibit peptidyltransferase
quinolones (ciprofloxacin)
interfere with type II topoisomerases and stabilize DNA double strand breaks
metronidazole
produce DNA radicals
sulfonamids and trimethoprim
Act to inhibit folic acid synthesis in bacteria
Bacitracin
Prevent recycling of lipid carrier
Polymixins
Binds phospholipids and disrupts inner/outer membranes of gram negative bacteria = topical and toxic
Isoniazid and Ethionamide
Inhibits SYNTHESIS of mycolic acid
Ethambutol
Inhibits ATTACHMENT of mycolic acid in the cell wall
Cycloserine
Cyclic analog of alanine; crosses blood brain barrier and is an NMDA receptor agonist
What are the polypeptide antibiotics?
Bacitracin
Polymixins
What are the beta-lactams?
Penicillins
Cephalosporins
Carbapenems
Monobactams
Penicillins
Mimicks the structure of D-Ala-D-Ala dipeptide; inhibits transpeptidation
What is the mechanism of resistance to penicillin?
Hydrolysis of B-lactam ring by B-lactamase
What is the mechanism of resistance to vancomycin (glycopeptides)?
Change in binding site in the peptidoglycan target
What is the mechanism of resistance to oxazolidinones (linezolid)?
Mutations in 23S rRNA
What is the mechanism of resistance to tetracyclines?
Efflux pump pushes drug out of cell
What is the mechanism of resistance to quinolones (ciprofloxacin)?
Mutations in genes encoding DNA gyrase and topoisomerase IV (type II topoisomerases)
