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. Extend normal flora to outcompete pathogens-
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 Normal
Acetylcholine (A) induces contraction
of muscle fibers
Botulism
Botulinum toxin, , blocks release of A,
inhibiting contraction

15. Tetanus Inhibitory Interneuron 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

17. Table 28-4

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

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

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

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

22. Disease Stages and Microbe Populations

23. Control of Infectious Disease
Drugs
Immunization
Sanitization
Future Challenges

24. 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