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22 Cards in this Set
- Front
- Back
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How did Ehrlich contribute to chemotherapy?
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By discovering salvarsan, the first chemotherapeutic agent used to treat syphillus
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What were the contributions of Fleming to chemotherapy?
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Discovered penicillin
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How did Dubos contribute to the field of chemotherapy?
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Dubos discovered the antibiotic gramicidin from a soil bacillus, thus stimulating the search for antibiotics from soil microbes.
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What was Waksman's contribution to chemotherapy?
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Waksman discovered the antibiotic streptomycin from a soil streptomyces, for which he received the Nobel Prize.
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What is MIC?
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Minimum inhibitory concentration is the lowest concentration of chemotherapeutic agent capable of preventing microbial growth (growth occurs if subcultured)
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What is MBC?
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Minimum bactericidal concentration is the lowest concentration of chemotherapeutic agent that kills bacteria. (No growth if subcultured)
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What was the first antibiotic?
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Penicillin
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What was the first antimicrobial/chemotherapeutic agent?
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Salvarsan found by ________?
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More than half (ie most) antibiotics are produced from what?
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Streptomyces, a filamentous bacteria the commonly inhabits the soil.
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Which drugs inhibit cell wall synthesis?
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Penicillin and cephalosporins prevent the crosslinking of peptidoglycan. Bacitracin and vancomycin interfere with the synthesis of the linear strands of peptidoglycan.
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Which drugs inhibit protein synthesis?
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Chloramphenicol-binds to 50S protion and inhibits formation of peptide bonds
erythromycin-binds to 50S portion prevents translocation-movement of ribosome along mRNA, streptomycin-changes shape of 30S portion, causes code on mRNA to be read incorrectly tetracyclines-interfere with attachment of tRNA to mRNA-ribosome complex |
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Most drugs that inhibit protein synthesis have broad spectrum of activity. Why doesn't erythromycin?
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It cannot penetrate the gram-negative wall and so affects mostly gram-positives.
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Which drugs cause injury to the plasma membrane?
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Polymyxin B-attaches to phosphlipids of membrane and changes its permeability
Antifungals - Nystatin, Amphotericin B, miconazole, and ketoconazole - combine with sterols to disrupt membrane |
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Why are nystatin and amphotericin B toxic to the host?
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Because they combine with sterols that are present in both fungal and eukaryotic membranes
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Which drugs inhibit nucleic acid replication and transcription?
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Quinolones, rifampin, idoxuridine
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How do the sulfanilamides (sulfa drugs) work?
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They competitively inhibit conversion of PABA to folic acid. Humans do not convert PABA, they ingest folic acid so it is selectively toxic. They are bacteriostatic.
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What are the antibacterial synthetics?
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Isoniazid (INH)-inhibits mycolic acid in mycobacteria (TB)
Ethambutol-same as INH but weaker Sulfonamides Quinolones and Fluroquinolones (norfloxacin and ciprofloxacin)-UTIs; affect cartilage so not given to children or preggos |
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What is the widely used sulfa drug combo?
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trimethoprim and sulfamethoxaole (TMP-SMZ); synergistic; inhibit sequential steps in purine synthesis (ie PABA to DNA/RNA precurors)
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What synthetics are there against fungus?
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Flucytosine interferes with protein synthesis and preferentially taken up by fungus
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Why is potassium clavulanate useful?
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It is an acid produced by a streptomycete that is a noncompetitive inhibitor of penicillinase. When attached to penicillin it prevents beta-lactam cleavage in the presence of penicillinase.
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Which drugs are useful against intracellular rickettsias and chlamydias?
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tetracyclines
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What is the potential side affect of chloramphenicol?
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aplastic anemia can result in 1:40,000
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