micro exam #4

  1. Know the causative agent for the following diseases: dental caries, shigellosis, typhoid fever, cholera, peptic ulcers and acute gastritis.
    • Dental caries: S. Mutans
    • Shigellosis: Shigella
    • Shigella dysenteriae - severe dysentery (worst kind, bacillary dysentery)
    • Shigella flexneri - dysentery
    • Shigella boydii - dysentery also Shigella, S. Sonnei Typhoid fever - Salmonella enterica serotype typhi
    • Cholera - Vibrio Cholerae
    • Peptic Ulcers- Helicobacter pylori
    • Acute gastritis - not sure.
  2. What is the difference between watery diarrhea, dysentery and enteric fever?
    • Watery diarrhea - Develops quickly and occurs frequently once you have it
    • Dysentery - Has blood and pus in it (this is the main, important difference)
    • Enteric fever - Systemic, (although focus is still on intestinal system) slower to develop
  3. How does food poisoning occur? How can you tell the difference?
    • Can result from two things:
    • -Infection: directly involves a pathogen
    • -Intoxication: Involves a toxin produced by a pathogen
    • Incubation time and severity depend on:
    • - Number of pathogens ingested --> infections.
    • - Amount of toxin ingested --> intoxications.
    • Incubation time is usually shorter in intoxications.
    • Intoxication may involve organs outside the digestive tract.
    • Botulism affects the central nervous system.
  4. What is the developmental process for dental plaque and carries?
    • Tooth surface becomes covered by pellicle, bacteria adhere to pellicle. This is facilitated by bacterial adhesion molecules. The initial adherent is usually strep mutans. Adhered bacteria grow and are joined by additional organisms including gram-positive cocci and gram-positive rods. After
    • 2-4 days, new layers of organisms have joined. These are followed by gram negative motile organisms. There can be as many as 400 species in
    • mature plaque
  5. What are the main differences between gingivitis and periodontitis?
    • Gingivitis- Inflammatory condition- Limited to the marginal surfaces of the gingival- Does not involve loss of bone- Can be corrected- Will continue as long as dental plaque remains
    • Periodontitis- Infection of the gingival- Results in loss of supportive bone and ligaments- Responsible for most tooth loss in adults
  6. What are the 5 types of E. coli?
    • Enterotoxigenic E. Coli (ETEC):
    • Toxin: Heat-labile and heat-stable
    • Lesion: Hypersecretion
    • Pathogenic gene location: plasmid
    • Transmission: fecal oral
    • Disease: Watery diarrhea
    • Enteropathogenic E. Coli (EPEC)
    • toxin: none
    • Lesion: Effacement (covering) of the small intestine
    • Pathogenic gene location: PAI
    • Transmission: Fecal-oral
    • Disease: Watery diarrhea
    • Enteroinvasive E. Coli (EIEC)
    • toxin: none
    • Lesion: Invasion and inflammation
    • Pathogenic gene location: large plasmid and PAI
    • Transmission: Fecal Oral
    • Disease: Dysentery
    • Enterohemorrhagic E. Coli (EHEC)
    • Toxin: Shiga toxin
    • Lesion: Effacement (covering) of colon and hemorrhage
    • Pathogenic Gene Location: PAI
    • Transmission: Fecal-oral, cattle
    • Disease: bloody diahrrea
    • Enteroaggregative E. Coli (EAEC)
    • toxin: none
    • lesion: adherent biofilm
    • pahtogenic gene location: none
    • transmission: none
    • disease: mucoid watery diarrhea
    • Common
    • Toxin: hemolysin
    • Lesion: inflammation
    • Pathogenic gene location: none
    • Transmission: Adjacent flora
    • Disease: Opportunistic
  7. Where does Salmonella and Campylobacter infection usually come from?
    Poor water quality, fecal contamination, undercooked meat, contaminated meat, pets
  8. Hepatitis A, B, C: transmission, chronicity, severity
    • Hep A
    • Transmission: fecal-oral, sexal
    • Chronicity: None
    • Severity: Usually mild
    • Hep B
    • Transmssion: fecal-oral, sexual, transfusion
    • Chronicity: 10 %
    • Severity: moderate
    • Hep C
    • Transmission: sexual, tansfusion
    • Chronicity: >50
    • Severity: mild
  9. the most common source of gastointestinal infection in the developed world is

    • E. campylobacter
    • -- back cook says a. salmonella but pg. 508 says clear as day campylobacter!
  10. The causative agent for 80% of ulcer is

    B. H. pylori
  11. an infection that is limited to the marginal surfaces of the gum tissue is called

    C. gingivitis
  12. dental plaque is an example of

    B. biofilm
  13. which of the following are produced by e. coli?

    E. all of the above
  14. transmission of traveler's diahrea occurs through

    B. contaminated food/water
  15. bacillary dysentery is caused by

    B. shigella
  16. serotypes of salmonella can be identified by

    B. O antigens
  17. the most important complication of typhoid fever is

    C. perforation of the colon wall
  18. the disease cholera is caused by

    A. colonization of the entire intestinal tract
  19. which of the following has now been classified as hepatovirus?

    D. hep a
  20. chronic carriers are the main reservoirs for

    D. hep b
  21. the intestinal parasite Giardia is found in

    E. all of the above
  22. rice stools are characteristic of

    C. cholera
  23. most of the normal microbil flora of the digestive system are found in

    B. large intestines
  24. poltury products are alikely source of infection by

    A. salmonella
  25. most gastrointestinal infections are tx w/

    A. water and electrolytes
Card Set
micro exam #4
chap 22 exam #4