Chapter 20 micro final.docx - \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa \u25aa Chapter 20 Antimicrobial Medication Quiz question CDAAABABFBCE Modern

Chapter 20 micro final.docx - u25aa u25aa u25aa u25aa...

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Chapter 20: Antimicrobial Medication Quiz question CDAAABABFBCE Modern Medicine is the Devil??? A Glimpse of History Paul Ehrlich (1854–1915) German physician and bacteriologist Observed some dyes stain bacterial but not animal cells Importance of Antimicrobial Medications Imagine a world without antimicrobial medications Prognosis for people with common diseases (for example bacterial pneumonia, severe staphylococcal infections) was grim before availability of penicillin in 1940s Physicians could identify cause, but only treatment was usually bedrest 20.1. History and Development of Antimicrobial Medications Discovery of Antimicrobial Medications Salvarsan (1910) first documented case Red dye Prontosil (1932) used to treat streptococcal infections in animals Both are chemotherapeutic agents Chemicals used to treat disease Antimicrobial medications or antimicrobials 20.1. History and Development of Antimicrobial Medications Discovery of Antibiotics In 1928, Alexander Fleming identified mold Penicillium excreting compound toxic to Staphylococcus Named compound penicillin Showed effective in killing many bacterial species ~10 years later, Ernst Chain and Howard Florey purified penicillin , and tested compounds in 1941 on police officer with life- threatening Staphylococcus aureus infection 20.2. Characteristics of Antimicrobial Medications Selective Toxicity: cause greater harm to microbes Interfere with essential structures or properties common in microbes but not human cells Therapeutic index Lowest dose toxic to patient / dose used for therapy Penicillin G useful, has high index; interferes with cell wall synthesis, a process not present in humans Medications too toxic for systemic use may be used topically Antimicrobial Action (how they work) Bacteriostatic- chemicals inhibit bacterial growth Patients defenses must still eliminate Bactericidal chemicals kill bacteria
20.2. Characteristics of Antimicrobial Medications Spectrum of Activity Broad-spectrum antimicrobials affect a wide range Important for treating acute life-threatening diseases Especially when no time to culture for identification Disrupt normal microbiota that help in keeping out pathogens Narrow-spectrum antimicrobials: affect limited range Requires identification of pathogen, testing for sensitivity Less disruptive to normal microbiota than the broad spectrum 20.2. Characteristics of Antimicrobial Medications Tissue Distribution, Metabolism, and Excretion Antimicrobials differ in behavior in body Only some medications cross the brain-blood barrier important in treating meningitis Some unstable at low pH, must be injected Rate of elimination or half-life dictates frequency Patients with kidney or liver dysfunction may differ Adverse (bad) Effects of Antimicrobials Include allergic reactions and toxic effects

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