Test 3: 38 antibiotics part 3 Flashcards
— interfere with attachment of tRNA to 30s mRNA ribosome complex
tetracyclines
— bind to 50S portion, prevents translocation- movement of ribosome along the mRNA
macrolide: erythromycin, azithromycin
chloramphenicol
lincosamide: lincomycin, clindamycin
binds to 50 S, A and P sites
aminoglycosides are dose or concentration dependent
concentration (dose SID)
bactericidal
aminoglycosides depend on — for active transport into bacteria via membrane pumps
oxygen
bactericidal (attack proteins synthesis- cause misreading)
Streptomycin A (prototype) Gentamycin A Kanamycin Amikacin Neomycin C (very toxic, external use only)
mechanism of action for aminoglycosides
Bind to both subunits and prevent ribosome function.
Other drugs bind only one subunit
Binding to 30S subunit interferes with tRNA attachment and misshapes the codon interaction region. This causes misreading.
bactericidal
cell membrane effect of aminoglycosides
cause holes in the bacteria cell membrane that lead to lysis
mechanism of action of tetracyclines
Bind to 30S subunit and block tRNA attachment
bacteriostatic
broad spectrum
Tetracycline, Doxycycline, Chlortetracycline, Oxytetracycline, Methacycline, Minocycline
— are some tetracyclines
Tetracycline Doxycycline Chlortetracycline Oxytetracycline Methacycline Minocycline
Bind to 30S subunit and block tRNA attachment
bacteriostatic
broad spectrum
mechanism of action for puromycin
Binds to A-site in 50S subunit and causes premature termination
not used in clinic- research drug similar to aminoacyl- tRNA
mechanism for macrolides
Bind to 50S subunit and prevent translocation along mRNA. Also blocks transpeptidase (Binds A and P site)
Bacteriostatic- lipid soluble- accumulates in tissues
Erythromycin (G+ > G-)
Azithromycin (G+ = G-)
mechanism of lincosamides
Same mechanism as Macrolides
(50S, A and P site binding)
Bacteriostatic
Gram +
Can neutralize endotoxin so have been used for toxic shock
Clindamycin
Lincomycin
— Can neutralize endotoxin so have been used for toxic shock
lincosamides
bacteriostatic Antibiotic that effects protein
Same mechanism as macrolides: Bind to 50S subunit and prevent translocation along mRNA. Also blocks transpeptidase (Binds A and P site)
lincomycin
clindamycin
mechanism for chloramphenicol
Similar mechanism as Macrolides and Lincosamides (50S, P site, inhibits transpeptidation )
Bind to 50S subunit and prevent translocation along mRNA. Also blocks transpeptidase
— most often used for dental disease (penetrates biofilm)
Clindamycin
type of lincosamide: bacteriostatic
Bind to 50S subunit and prevent translocation along mRNA. Also blocks transpeptidase (Binds A and P site)
most antibiotics that are protein synthesis inhibitors are — except for —
bacteriostatic: tetracyclines, puromycin,macrolides, lincosamides, chloramphenicol
aminoglycosides: bacteriocidal
Aminoglycosides works on which subunit of the ribosome
both 30S and 50S
different from other protein synthesis inhibitors that only work on one
— is a protein synthesis inhibitor, can puncture the cell wall and is bactericidal
aminoglycoside
Drugs affect the ribosome by binding and either inhibiting interactions (—) or changing the shape of the subunits (—)
transpeptidase
aminoglycosides
what are two antibiotics that inhibit folic acid metabolism
Sulfonamides
Trimethoprim
mammals do NOT make their own folic acid
folic acid is used for portein and nucleic acid metabolism
what are some sulfonamides
Family includes Sulfanilamide, Sulfadiazine, Sulfimethoxine, Sulfapyridine, Sulfizoxazole, Sulfazalazine and Sulfamethoxazole
inhibit folic acid metabolism
bacteriostatic- but when used in combo with trimethoprim becomes bacteriocidal
broad spectrum
what happens when you use sulfonamides and trimethoprim
bacteriocidal
drugs inhibit folic acid synthesis in bacterial
they are bacteriostatic alone, but bacteriocidial when working together
mechanism of action of sulfonamides and trimethoprim
- Sulfa drugs mimic pABA (block DHFS)
- Trimethoprim inhibits DHFR Folic Acid
- Bacterial DHFR > 6x104 more sensitive
than mammalian DHFR.
inhibit folic acid metabolism in bacteria
mechanism of action for polymyxin B
Polymyxins are cationic detergents that bind to LPS in Gram –ve Bacteria and disrupt the phospholipid bilayer - increases permeability and causes osmotic changes leading to bacterial death
inhibit cell membrane function
— is a Pro-drug – activated in acid environment where it hydrolyses to produce formaldehyde
methenamine (mandelate/ hippurate)
bactericidal, broad spectrum
isoniazid (INH)’
bactericidal antibiotic againist mycobacteria
Inhibits mycolic acid synthesis by inactivating Fatty Acid Synthase (FAS)-II
Pro-drug activated by a bacterial catalase named KatG
— inhibits mycolic acid synthesis by inactivating Fatty Acid Synthase (FAS)-II
isoniazid (INH)’
prodrug
bactericidal
works againist mycobacteria
— inhibits incorporation of mycolic acid into Arabinogalactan to make the cell wall
ethambutol (EMB)
