Lecture 5 Flashcards
What are the mechanisms of action of a/bs? (3)
Cell wall - beta-lactams & glycopeptides
PRO syn - tetracyclines, macrolides, aminoglycosides & more
DNA metabolism - Fluoroquinolones, metronidazole, folate syn inhibitors
Min inhibitory [ ] (MIC)
Min [ ] of an a/b that will inhibit the growth of an organism
Min bactericidal [ ] (MBC)
Min [ ] of an a/b that will kill an organism
Bacteriostatic is MBC ___ 4X MIC
MBC > 4X MIC
Bactericidal is MBC ___ 4X MIC
MBC 4X MIC
What pharmacodynamic properties of a drug effect your dosing regime?
[ ] & time dependent
Why is the [ ] of a drug important when deciding on tx regime?
B/c the activity of the antimicrobial relies on how far you are able to exceed the MIC at the site of the infection
Why is the time of a drug important when deciding on tx regime?
Activity of the a/b relies on how long you are able to maintain drug [ ]s above the MIC at the site of infection
Describe the mechanism of beta-lactams
Inhibit cell wall syn by binding to penicillin binding PROS (transpeptidases & carboxypeptidases) & prevent the final stage of peptidoglycan syn
Are beta-lactams bactericidal or bacteriostatic?
bacteriocidal
What a/bs are beta-lactams?
Penicillins
Cephalosporins
Carbapenems
beta-lactamase inhibitors
What is the mechanism of action for tetracyclines?
PRO syn inhibitors by binding to the 30S ribosomal subunit
Are tetracyclines bactericidal or bacteriostatic?
Bacteriostatic
What a/bs are tetracyclines?
Oxytetracycline
Doxycycline
Minocycline
What is the mechanism of action for fluoroquinolones?
Inhibit DNA syn by biting to topoisomerase (DNA supercoiling enzyme)
Are fluoroquinolones bactericidal or bacteriostatic?
Bactericidal
What a/bs are fluoroquinolines?
Naladixic acid - limited spectrum
Ciprofloxacin/enrofloxacin - broad spectrum
Moxifloxacin/levofloxacin - extended spectrum
What is the mechanism of action for aminoglycosides?
PRO syn inhibitors
Are aminoglycosides bactericidal or bacteriostatic?
bactericidal
MLSbK mechanism of action?
PRO syn inhibitors by binding to 50S ribosomal subunit
Are MLSbK bactericidal or bacteriostatic?
Bacteriostatic
What a/bs are MLSbK? (5)
Macrolides Lincosamides Streptogramins Ketolides Azalides
What is the mechanism of action of Chloramphenicol?
PRO syn inhibitor
Are Chloramphenicol a/bs bactericidal or bacteriostatic?
Bacteriostatic
What a/bs are banned in food animals?
Chloramphenicol
Metronidazole - carcinogenic
What is the mechanism of action of metronidazole?
Damage DNA & interfere with repair mechanisms
Is metronidazole bactericidal or bacteriostatic?
Bacteriocidal
What type of organisms does metronidazole target?
Anaerobic bacteria
Gram positive & negative bacteria
What organisms does chloramphenicol target?
broad spectrum
gram negatives & positives
What organisms do aminoglycosides target?
Staphylococcus
What organisms do Tetracyclines target?
Broad spectrum
gram positives & negatives
What is the mechanism of action for folate syn inhibitors?
Inhibit folic acid syn by competitively binding to the PABA portion of the folate molecule
Are folate syn inhibitors bactericidal or bacteriostatic?
Bacteriostatic
What organisms do folate syn inhibitors target?
Broad spectrum
Gram positives & negatives
Protozoans & Toxoplasma
When do we use anti-gram positives?
last resort
What a/bs are anti-gram positives? (4)
Glycopeptides
Lipoglycocpeptides
Ozaxolidonones
Peptide a/bs
