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Antimicrobial Agents

Antimicrobial Agents. Antimicrobial agents. Antibiotics – bacteria Antifungals – fungus Antiprotozoans – protozoa Antihelminths – worms. Infection. It has only been in the last 150 years that we have realized that infections were caused by other living organisms residing in the host.

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Antimicrobial Agents

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  1. Antimicrobial Agents

  2. Antimicrobial agents • Antibiotics – bacteria • Antifungals – fungus • Antiprotozoans – protozoa • Antihelminths – worms

  3. Infection • It has only been in the last 150 years that we have realized that infections were caused by other living organisms residing in the host

  4. Infection • Localized – limited to one area like skin, eyes, ears or mucosa • Systemic – infection involves the body

  5. Infectious Disease • There are many, many disease processes that are caused by infection • There are many, many terms to describe infection

  6. Microbiology • The study of these microbes is covered in microbiology (microscopic biology).

  7. Basic Micro Terms for Antibiotics • Bacteriostatic – prevent bacteria reproduction • Bacteriolytic – cause bacteria death

  8. The age of antibiotics • Although there have been cultures that used plants and minerals to treat infectious diseases for centuries • Our understanding of infectious disease and the scientific use of antibiotics is less than a century old

  9. Many horrible diseases are no longer killing the masses worldwide • Learn the history of infectious disease and the human suffering it has caused

  10. Proper sanitation and clean water have done more to combat infectious disease than anything else

  11. Sulfonamides • Sulfonamide drugs were the first antimicrobial drugs • Paved the way for the antimicrobial revolution in medicine

  12. Sulfonamides • The first sulfonamide was trade named Protonsil, which is a prodrug of an active sulfonamide. • Experiments with Prontonsil began in 1932 in the laboratories in the laboratories of Bayer AG.

  13. Sulfonamides • Prontonsil was the first medicine ever discovered that could effectively treat a range of bacterial infections. • It had no effect at all in a test tube or petri dish, exerting its antibacterial action only in live animals.

  14. Sulfonamides • Antibacterial sulfonamides act to prevent a key step in folate synthesis • Since folate is necessary for cells to synthesize nucleic acids… • Preventing folate acid synthesis prevents cells from dividing

  15. Sulfonamides • Because the sulfonamide antibacterial prevent reproduction of the bacteria they are…

  16. Sulfonamides • Folate is synthesized in mammalian cells, it is a dietary requirement • This explains the selective toxicity in bacteria

  17. Sulfonamides • Sulfacetamide as topical for bacterial conjunctivitis • Silver sulfadiazine cream for burn wounds

  18. BactrimSeptraSMX/TMP • Sulfamethoxazole with Trimethoprim are used in combination as a potent antibiotic combination • Trimethoprim is also a folate synthesis inhibitor

  19. Sulfonamide • Sulfonamides led to the development of many sulfa-based drugs: • Sulfonylureas – for diabetes mellitus • Thiazide diuretics – for hypertension

  20. Sulfonamide • Unfortunately, sulfonamides cause allergic reactions in nearly 5% of the population • Is a leading cause of a drug induced Stevens-Johnson syndrom – a type of allergic reaction

  21. Stevens-Johnson syndrom

  22. Polyketides • Polyketides are metabolites from bacteria, fungi, plants and animals.

  23. Polyketides • Ancient wisdom gave us the knowledge that certain plants and molds were helpful in preventing what we call infection

  24. Penicillin • It has been known since the ancients that certain molds had healing properties • Modern scientific investigation of these properties emerged as early as 1875.

  25. Penicillin • Although the antimicrobial properties of penicillin were well accepted • Mass production of penicillin was difficult until 1940s. • It was common procedure to collect the urine from patients being treated so that the penicillin could be isolated and reused.

  26. Penicillin • Thanks to a lot of researchers, and a moldy cantaloupe in Peoria, Illinois… • By 1944, PCN was in full mass production

  27. Penicillin • Penicillin was used to treat Gonorrhea before but now it is no longer being used since the bacteria evolved to resist the antibiotic

  28. However… • Some bacteria, which had never caused infections before penicillin, emerged as pathogens…

  29. Beta-lactam antibiotics • Penicillins • Cephalosporins • Carbapenems

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