abx Flashcards
cell wall synthesis inhibitors
- beta lactams = penicillin, amoxicillin, nafcillin, ampicillin, methicillin, cephalosporins
- –peptidoglycan cross linking
- –allergy
- –altered PBP, beta-lactamase - glycopeptides = vancomycin
- –peptidoglycan chain elongation
- –skin rash
- –alteration of terminal aa on NAM
beta-lactams (6)
(cell wall synthesis inhibitor – other class is glycopeptides)
“illin” = penicillin, amoxicillin, nafcillin, ampicillin, methicillin & cephalosporins
–target peptidoglycan cross linking
–allergy side effect
–resistance from altered PBP & beta-lactamases
glycopeptides
(cell wall synthesis inhibitors – other class is beta-lactams)
vancomycin
- -target peptidoglycan chain elongation
- -side effect skin rash
- -resistance if bacteria alter terminal AA of NAM
protein synthesis inhibitors (6 categories)
- aminoglycosides (‘mycin’ but not erythro, azithro, or clinda) - target 30S
- tetracylcine (‘cyline’) - target 30S
- chloramphenicol (chlormycetin) - targets 50S (DANGER)
- fusidic acid - targets elongation factor (DANGER)
- macrolides (erythro/azithromycin) - target 50S
- Lincosamides (clindamycin) - target 50S
aminoglycosides (5)
(protein synthesis inhibitor)
- streptomycin
- gentamycin
- kanamycin
- neomycin
- tobramycin
- -target 30S irreversibly to prevent initiation
- -SE: nephrotoxicity, deafness (TOPICAL, if systemic – monitor!!)
- -Res: mutant 30S, block import, efflux
tetracycline
(protein synthesis inhibitor)
- tetracycline & doxycycline
- target 30S reversibly to prevent tRNA docking (bacteriostatic)
- oral or in mouthwash
- SE: stain bone and teeth (dont give to kids) & GI distress
- res: efflux pump
chloramphenicol
(protein synthesis inhibitor) = chlormycetin -target 50S irreversibly - SE potentially fatal (shut down RBC adn WBC production in bone marrow) -only use in life threating situation
fusidic acid
(protein synthesis inhibitor)
- block elongation factor G to prevent ribosome translocation
- possibly toxic to mammalian 80S – NOT AVAILABLE IN USA
Macrolides and Lincosamides
(protein synthesis inhibitor)
- reversibly bind 50S (b.static, except in high doses b.cidal)
- —macrolides (erthyromycin&azithromycin)—block ribosomal translocation on growing chain
—-lincosamides (clindamycin)—block peptide bond formation
- broad spectrum, alternative for penicillin if allergic
- res: mutant 23s rRNA of 50S SU
lincosamides vs macrolides
- both reversibly bind 50S to inhibit protein synthesis
- lincosamides = clindamycin; block peptide bond formation **ANEAROBIC – drug of choice
- macrolides = azythro/erythromycin; block ribosomal translocation on growing chain
- minimal side effects (GI) & both broad spectrum
- res: alter 50S SU; efflux pump; enzymatic inactivation; decreased permeability
nucleic acid synthesis inhibitors (4)
- sulfonamides (sulfa drugs) - prevent folic acid formation (dihydropteroate synthetase)
- trimethoprim - blocks THF production (dihydrofolate reductase)
^^both block nucleotide synthsis - quinolones (levofloxin, ciprofloxin, nalidix acid) - block DNA gyrase (DNA replication)
- rifamycins (rifampin, rifamycin) - block beta-SU of RNA polymerase (RNA synthesis)
sulfonamides
sulfa drugs, block nucleotide synthesis
- *not antibiotics – antimetabolite
- block dihydropteroate synthetase to prevent folic acid formation (needed for THF, which is needed for purine synthesis)
- SE: allergy (me!)
- Res: mutant dihydropteroate synthetase binds PABA better than it binds drug
trimethoprim
blocks nucleic acid synthesis by blocking dihydrofolate reductase, which is needed to make THF from folic acid (THF needed for purine synthesis)
- SE: allergy
- Res: some bacteria use exogenous THF
