what antibiotic classes /drug inhibit cell wall synthesis?
- all are bactericidal.
- natural penicillins: PCN V and PCN G.
- semi-synthetic penicillins: Oxacillin.
- aminopenicillins: Ampicillin.
- penicillin + B-lactamase inhibitor: Amoxicillin + clavulanic acid = Augmentin.
- Carbapens: Imipenem/cilastatin = Primaxin.
- Monobactam: Aztreonam.
- Cephalosporins: 1st gen = only gm (+)
2nd - 5th gen = extended spectrum.
NON B-LACTAM RINGS
8. polypeptide: Bacitracin and Vancomycin.
ANTIMYCOBACTERIAL
9. anti-mycolic acid: Isoniazid and Ethambutanol.
what drugs inhibit protein synthesis?
- all are bacteriostatic.
- Nitrofurantoin: attacks bacterial ribosomal proteins. PRODRUG.
- Chloramphenicol: attacks the 50s subunit of the 70s ribosome.
- Aminoglycoside family: streptomycin, neomycin, and gentamycin. attack the 30s subunit of the 70s ribosome.
- Tetracycline: interferes with tRNA attachment, what binds the amino acid to the mRNA strand.
- Macrolides: Erythromycin; blocks the ribosomal tunnel.
what drugs inhibit nucleic acid replication?
- are all bactericidal.
- Rifamycin: Rifampin; mycobacteria. red urine and tears.
2: Quinolones aka Fluroquinolones: Ciprofloxacin (Cipro); causes the inhibition of DNA gyrase.
what drugs injure the plasma membrane?
- are all bactericidal.
- Lipopeptides: Polymycin B; disrupts the fatty acid biosynthesis.
what drugs cause competitive inhibition of essential metabolites?
- bactericidal.
- sulfanamides: sulfanilamide + trimethoprim.
drug synergism.
Paul Ehlrich
“magic bullet” and selective toxicity.
Alexander Flemming
S. aureus inhibited by penicillin mold; first ABX.
selective toxicity
selectively finding and destroying pathogens without damaging the host.
chemotherapy
the use of chemicals to treat disease.
antibiosis
the MECHANISM of inhibitory action.
antibiotic
a substance/med produced by the microbe itself that in small amounts inhibits another microbe (organic).
antimicrobial drugs
FULLY SYNTHETIC.
semi-synthetic
substances chemically modified or manipulated in the lab.
narrow spectrum
gm - OR gm +
broad spectrum
gm + AND gm -
bacteriostatic
inhibits bacterial growth
bacteriocidal
kills all microbes.
superbug
bacteria that are resistant to a large number of ABX.
half of ABX are produced by
Streptomyces
the target of antifungal drugs
injure the plasma membrane and target the sterols since fungi have ergosterol present instead of cholesterol.
- interrupting the biosynthesis kills the cell and injures the plasma membrane, causing cellular contents to leak out.
antifungal drugs include
- Polyenes
i. Nyastatin: treats thrush or oral candida. - Azoles
i. imidazoles like Clotramazole and Micoazole.
treats tropical infections of the skin.
Kirby-Bauer Test
measures the zone diameter of the ABX compared to a table.
MIC: minimum inhibitory concentration. the smallest effective dose to inhibit growth.
inversely related to the zone of inhibition.
small zone = big MIC : need more chemicals to inhibit growth.
big zone = small MIC : less chemicals needed to inhibit growth.
E-Test
determines MIC using an epsilometer with the ABX.
only tests one drug.
broth dilution test
determines the MIC (minimum inhibitory concentration) and the MBC (minimal bacteriocidal concentration).
tests if the bacteria is able to grow at all ABX concentrations, when its resistant and sensitive.
