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Strategic Bacterial Pathogenicity: Understanding Mechanisms and Toxins

Explore bacterial strategies for pathogenicity and virulence through portals of entry, infectious dose, adherence, penetration, toxins, and more. Learn about mechanisms of pathogenicity, including toxins, portals of exit, and how pathogens overcome host defenses.

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Strategic Bacterial Pathogenicity: Understanding Mechanisms and Toxins

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  1. Game Plan Lecture Disease pathogenesis Portals of entry Mechanisms of pathogenicity Toxins Lab SSE Unknowns

  2. Bacterial strategies for pathogenicity and virulence • Portals of entry • Infectious dose • Adherence • Penetration, evasion and damage • Portals of exit

  3. 1. Portals of entry

  4. 1. Portals of entry

  5. 2. Infectious Dose- ID50

  6. 3. Adherence 1. Capsules 2. Pili and fimbriae 3. Adhesins • Glycoproteins • Lipoproteins 4. Other Figure 15.1 - Overview

  7. 4. Penetration, evasion and damage • Hyaluronidase • Coagulase • Kinase • 4. IgA protease • 5. Leukocidins

  8. 4. Penetration, evasion and damage TOXINS

  9. Exotoxins

  10. Types of Exotoxins: 1. A-B toxins Ex. Clostridium botulinum toxin

  11. Botulinum toxin (BOTOX) prevents acetylcholine release at neuromuscular junction http://www.botoxmedical.com/Blepharospasm/MechanismOfAction

  12. BOTOX: medical applications Blepharospasm Joseph Jankovic, M.D., professor of neurology, Baylor College of Medicine, Houston, Texas Hyperhidrosis

  13. BOTOX: cosmetic applications

  14. Types of Exotoxins: 2. Membrane disrupting or cytolytic toxins Ex. Hemolysins of Staphylococcus aureus and Streptococcus pyogenes

  15. Types of Exotoxins: 3. Superantigens Ex. Staphylococcal and Streptococcal toxins that cause toxic shock syndrome

  16. Types of Exotoxins: 4. Genotoxins Ex. Cytolethal Distending Toxin (CDT) that causes mutations, disrupts cell division and may lead to cancer

  17. TOXINS Table 15.2

  18. Endotoxins

  19. Endotoxins

  20. Mechanisms of pathogenicity

  21. Independent Study Download and print APO-5: Microbes and you- who will win the war? Feel free to modify word doc so that you have room to write out answers. TYPED APO is due on the day of Exam 3.

  22. This APO will encompass several lectures and includes Chapters 15-18. It is due the day of Exam 3. Mechanisms of Virulence For each virulence factor below, describe whether it contributes to increased virulence by being invasive or toxic or both, and how it helps the pathogen to overcome a host defense mechanism. 1. Neisseria gonorrhea produces pili and adhesins specific to the human urogenital epithelium. 2. The pilin genes in Neisseria gonorrhea periodically recombine. 3. Many Streptococcus strains coat themselves in a slimy glycocalyx. 4. Staphylococcus aureus can synthesize hemolysins. 5. Chlamydia infects a host phagocyte and prevents lysosome fusion. Etc.

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