MIC 205 1st Edition Lecture 18Outline of Last LectureI. Etiology and InfectionII. Reservoirs of InfectionIII. Manifestations of DiseaseIV. Stages of Infectious DiseasesV. VirulenceOutline of Current Lecture VI. Controlling microbial growth in the bodyVII.Current Lecture Drugs- Used to control growth of microbes in the body- Therapeutic advantageso Chemicals that affect physiology Chemotherapeutic agents that include antimicrobials designed to treat infections- Ex: penicillin, amoxicillin, ibuprofen, acetaminophen, caffeine, alcohol, THC (pot), meth, heroine Most antimicrobials are secondary metabolites produced by fungi and bacteriaHistory of Drugs- Salvarsan (arsphenamine)- 1910 (Paul Ehrlich)o First modern chemotherapeutic agent- Penicillin- 1929 (Alexander Fleming)o Available routinely in 1940s- Sulfanilamide- 1032 (Gerhard Domagk)o First widely and practical antimicrobial agento Inhibits metabolic synthesis of RNA and DNA nucleotidesKey factors for antimicrobial actionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Selective toxicity- kill pathogen and not kill humano Antibacterial drugs constitute the largest number of antimicrobialso Few for eukaryotic (protozoan) diseaseso Rare effective antiviral drugsMechanisms of Antimicrobial Action: (Picture—Study for exam)- Drug targets: o Cell wall synthesiso Protein synthesiso Membrane integrityo Metabolismo Nucleic acid synthesis Cell wall synthesis inhibitor- Beta-lactams target bacterial cell wallo Prevent cross links of NAMo Effective ONLY for growing cells Requires new peptidoglycan to be laid down No effect on plant/animal cells Inhibition of protein synthesis- Prokaryotic ribosomes = 70 s in size- Eukaryotic ribosomes = 80 so Can kill bacteria without hurting human However our mitochondria ribosomes are relative to bacterial ribosomes (possibly affecting humans through drug side affects)o Tetracyclines, streptomycin, erythromycin drugs used in the community Disruption of cytoplasmic membrane- Damage the integrity of the cytoplasmic membraneo Amphotericin B (antifungal agent) Causes a hole in the cytoplasm Inhibition of metabolic pathways- Antimetabolic agents Kill actively growing vegetative cells by not letting them generate ATPo Sulfa drugs used for biosynthesis of DNA and RNA- REVIEW:o Ideal microbial agent: inexpensive non-toxic (safe for humans) non-allergenic fast-acting readily distributed broad spectrum stable chemicallySpectrum of Action- varies based on what you want to kill- killing normal microbes, loses benefits of those good microbes in your bodyEfficacy of antimicrobial agents- Kirby-bauer disc diffusion- MIC (minimum inhibitory concentration) tests- MBC (minimum bactericidal concentration)
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