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HOST–MICROBE RELATIONSHIPS AND DISEASE PROCESSES

HOST–MICROBE RELATIONSHIPS AND DISEASE PROCESSES. CHAPTER 14. Symbioses. Mutualism- Both parties benefit example E. coli in gut Commensalism- One party benefits, other does not. example Staph Aureus on skin. Photo of mixed bacteria on skin. Symbioses. Parasitism Opportunism.

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HOST–MICROBE RELATIONSHIPS AND DISEASE PROCESSES

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  1. HOST–MICROBE RELATIONSHIPS AND DISEASE PROCESSES CHAPTER 14

  2. Symbioses • Mutualism- Both parties benefit example E. coli in gut • Commensalism- One party benefits, other does not example Staph Aureus on skin Photo of mixed bacteria on skin

  3. Symbioses • Parasitism • Opportunism One party benefits, other harmed Pinworms on anus

  4. Infection and Disease • Contamination-organisms present • Infection- organisms multiply • Disease- disturbance of health

  5. Pathogenicity Concepts • Pathogenicity- capacity to produce disease • Virulence/Avirulence - intensity of disease E. coli k12 nonpathogenic E. coli O157:H7 = pathogenic

  6. Normal Microflora • Populations • Resident • Transient

  7. probiotics - Extend normal flora to outcompete pathogens

  8. Koch’s Postulates • 1. specific causative agent must be observed • 2. The agent must be isolated and grown in pure culture. • 3. Hosts must get the same disease when inoculated. • 4. The agent must be reisolated and show to be the same causative agent.

  9. Satisfying Koch’s Postulates

  10. Kinds of Disease • Infectious/Non-infectious-caused by organism • Communicable/Non-communicable Pneumonia / Emphysema Can be transmitted or not HIV / ulcer

  11. How Microbes Cause Disease • Direct Action- adherence, colonization, enzyme action • Bacterial Toxins- exotoxins, endotoxins, • Cytopathic Effects - hemolysis, loss of membrane integrity Cholera, botulism Salmonella, Staph

  12. Hemolysis Alpha-green halo hemoglobin oxidation Beta - complete hemolysis agar clearing Gamma - no hemolysis or discoloration Blood agar with 3 organisms

  13. Virulence Factors

  14. Botox Excitation signals from the central nervous system Muscle Botulism Botulinum toxin, , blocks release of A, inhibiting contraction Normal Acetylcholine (A) induces contraction of muscle fibers

  15. Inhibitory Interneuron Tetanus Excitation signals from the central nervous system Tetanus toxin Muscle Tetanus Tetanus toxin binds to inhibitory interneurons, preventing release of glycine (G) and relaxation of muscle

  16. Table 28-4

  17. Sign Symptom Syndrome Sequelae Acute Chronic Subacute Latent Vocabulary Terms

  18. Local infection Focal infection Systemic infection Septicemia Bacteremia Viremia Vocabulary Terms (2)

  19. Primary infection Secondary infection Superinfection infection with another virus (discuss HIV and CMV) Mixed infection Inapparent (subclinical) infection Vocabulary Terms (3)

  20. Incubation Prodromal Invasive Decline Convalescence Infectious Disease Stages Migraine example

  21. Disease Stages and Microbe Populations

  22. Control of Infectious Disease • Drugs • Immunization • Sanitization • Future Challenges

  23. Protection from disease Removal of particles including microorganisms by rapid passage of air over cilia in nasopharynx Lysozyme in tears and other secretions dissolves cell walls Mucus, cilia lining trachea suspend and move microorganisms out of the body Skin is a physical barrier, produces antimicrobial fatty acids, and its normal flora inhibit pathogen colonization Mucus and phagocytes in lungs prevent colonization Blood and lymph proteins inhibit microbial growth Stomach acidity (pH 2) inhibits microbial growth Rapid pH change inhibits microbial growth Normal flora compete with pathogens Normal flora compete with pathogens in the gut Flushing of urinary tract prevents colonization

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