Antibiotics Flashcards
What antibiotics are cell wall inhibitors? (5)
1) Penicillins
2) Cephalosporins
3) Monobactams
4) Carbapenems
5) Glycopeptides
What is the mechanism of action for beta lactam antibiotics?
Target and inhibit penicillin-binding protein, which are enzymes found anchored in cell membrane and are involved in linking of bacterial cell wall, to disrupt the cell wall synthesis
What is the mechanism of resistance in beta lactam antibiotics?
Beta lactamase
What is the specific side effect of pencillin and cephalosporin antibiotics?
1) Hypersensitivity
2) GI side effects
What is spectrum of activity for penicillins?
1) Gram + aerobes
2) Anaerobes
3) Potentiation adds more gram -
Are cell wall inhibiting antibiotics cidal or static?
Bactericidal
What is an example of monobactam?
Aztreonam - synthetic beta lactam
What changes in spectrum do we see with increases in cephalosporin generation?
1) 1st = gram positive aerobes (Ex: cephalexin)
2) 2nd = gram +/- aerobes, anaerobes (Ex: cefoxitin)
3) 3rd = gram negative (Ex: ceftiofur)
4) 4th = gram negative, MDR
What is the spectrum of action of carbapenems?
Gram +/- aerobes and anaerobes
What is the mechanism of action of vancomycin?
Cell wall synthesis inhibitor via prevention of amino acid addition to cell wall
What is the spectrum of action for vancomycin?
Gram + (MDR), anaerobes
What are example of nucleic acid inhibiting antibiotics? (4)
1) Fluoroquinolones
2) Nitroimidazole (i.e. metronidazole)
3) Rifamycin (i.e. rifampin)
4) Trimethoprim sulfa
What is the mechanism of action for fluoroquinolone antibiotics?
Bind gyrase and topoisomerase-4 and stops DNA and protein synthesis
What is the mechanism of resistance with fluoroquinolone antibiotics?
Gyrase mutations
Decreased membrane permeability
Drug efflux
What are side effects associated with fluoroquinolones?
1) CNS and retinal degeneration in cats
2) Cartilage toxicity in growing animals
Name all static antibiotics (5 classes)
1) Sulfonamide (potentiation w/ TMS becomes cidal)
2) Chloramphenicol
3) Macrolides
4) Lincosamides
5) Tetracyclines
What is the mechanism of action of metronidazole (nitroimidazole)?
Removes electrons from transport chain, creating free radicals that damage DNA
What is the side effects of vancomycin? (4)
1) Hypersensitivity
2) Renal toxicity
3) Ototoxicity
4) Bone marrow suppression
What is the mechanism of action of rifamycin (i.e. rifampin)?
Inhibits beta-subunit of DNA-dependent RNA polymerase, inhibiting nucleic acid synthesis
What is the spectrum of activity of rifampin and what is it used for?
1) Gram + (MDR Staph) and Strep
2) Alternative treatment for E. canis
3) In combo w/ antifungals
What are the side effects of rifampin?
1) Red/orange urine
2) Hepatopathy
3) P450 enzyme induction
What is the mechanism of action of TMS?
Inhibit folic acid metabolism by blocking conversion of PABA to DFA and DFA to tetrafolic acid by inhibiting dihydrofolate reductase = no folate = no purines = no DNA
What is the spectrum of action of TMS?
Gram +/- aerobes
What are the side effects of TMS?
1) KCS
2) Hypersensitivity
3) Hepatopathy - acute neutrophilic hepatitis with icterus
4) Immune-mediated disease
5) Hypothyroidism w/ long term therapy
What antibiotics are protein synthesis inhibitors? (5)
1) Aminoglycosides
2) Chloramphenicol
3) Macrolides
4) Lincosamides
5) Tetracyclines
Which antibiotics inhibits 30s ribosomal subunit? (2)
1) Aminoglycosides
2) Tetracycylines
Which antibiotics inhibit 50s ribosomal subunit? (3)
1) Chloramphenicol
2) Macrolides
3) Lincosamides
What is the spectrum of action of aminoglycosides?
Gram +/-
Not good against anaerobes
What is the spectrum of action of chloramphenicol?
Gram +/- aerobes
Anaerobes
Some rickettsial organisms
What is the spectrum of action of macrolides and lincosamides?
Gram +
Some gram negative (more than penicillins)
Anaerobes
What is the spectrum of action of tetracyclines?
Gram +/-
Aerobes
Some anaerobes
Intracellular bacteria
