Your SlideShare is downloading. ×
Chapter 22b - Lecture Outline
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Chapter 22b - Lecture Outline


Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total Views
On Slideshare
From Embeds
Number of Embeds
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

No notes for slide


  • 1. Microbiology: A Systems Approach, 2 nd ed. Chapter 22: The Gastrointestinal Tract and Its Defenses
  • 2. Acute Diarrhea Caused by E.coli O157:H7 (EHEC)
    • Most virulent strain of E. coli
    • Enterohemorrhagic E. coli
    • Symptoms range from mild gastroenteritis with fever to bloody diarrhea
    • About 10% of patients develop hemolytic uremic syndrome (can cause kidney damage and failure)
    • Can also cause neurological symptoms such as blindness, seizure, and stroke
  • 3. Figure 22.12
  • 4. Acute Diarrhea Caused by Other E. coli
      • Four other categories:
        • Enterotoxigenic
        • Enteroinvasive
        • Enteropathogenic
        • Enteroaggregative
  • 5. Enterotoxigenic E. coli (ETEC)
    • Presentation varies depending on which type of E. coli is causing the disease
    • Traveler’s diarrhea : watery diarrhea, low-grade fever, nausea, and vomiting
  • 6. Enteroinvasive E. coli (EIEC)
    • Cause a disease similar to Shigella dysentery
    • Invade gut mucosa and cause widespread destruction
    • Blood and pus found in stool
    • Significant fever
  • 7. Enteropathogenic E. coli (EPEC)
    • Profuse, watery diarrhea
    • Fever and vomiting also common
    • Produce effacement of gut surfaces
  • 8. Enteroaggregative E. coli (EAEC)
        • Can cause chronic diarrhea in young children and in AIDS patients
  • 9. Acute Diarrhea Caused by Campylobacter
    • Most common bacterial cause of diarrhea in the U.S.
    • Frequent watery stools, fever, vomiting, headaches, and severe abdominal pain
    • Symptoms may last beyond 2 weeks
    • Symptoms may subside then recur over a period of weeks
    • In a small number of cases, can lead to a serious neuromuscular paralysis called Guillain-Barré syndrome (GBS)
  • 10. Figure 22.13
  • 11. Acute Diarrhea Caused by Yersinia Species
    • Y. enterocolitica and Y. pseudotuberculosis
    • Uncommon in U.S.
    • Inflammation of the ileum and mesenteric lymph nodes gives rise to severe abdominal pain
    • Infection occasionally spreads to the bloodstream
  • 12. Acute Diarrhea Caused by Clostridium difficile
    • Causes pseudomembranous colitis
    • Major cause of diarrhea in hospitals
    • Able to superinfect the large intestine when drugs have disrupted the normal biota
    • Produces two enterotoxins (toxins A and B) that cause areas of necrosis in the wall of the intestine
    • Diarrhea
    • Severe cases exhibit abdominal cramps, fever, and leukocytosis
  • 13. Figure 22.14
  • 14. Acute Diarrhea Caused by Vibrio cholera
    • Incubation period of a few hours to a few days
    • Symptoms begin abruptly with vomiting
    • Followed by copious watery feces called secretory diarrhea
    • Can lose up to 1 liter of fluid an hour in severe cases
  • 15. Figure 22.15
  • 16. Acute Diarrhea Caused by Cryptosporidium
    • Headache, sweating, vomiting, severe abdominal cramps, and diarrhea
    • In AIDS patients may develop into chronic persistent cryptosporidial diarrhea
  • 17. Figure 22.16
  • 18. Figure 22.17
  • 19. Acute Diarrhea Caused by Rotavirus
      • Effects of infection vary with age, nutritional state, general health, and living conditions of the patient
  • 20. Figure 22.18
  • 21. Acute Diarrhea Caused by Other Viruses
    • Many other viruses can cause gastroenteritis
    • For example adenoviruses, noroviruses, and astroviruses
    • Common in the U.S. and around the world
    • Profuse, water diarrhea of 3 to 5 days duration
  • 22.  
  • 23.  
  • 24. Acute Diarrhea with Vomiting (Food Poisoning)
    • Symptoms in the gut that are caused by a preformed toxin of some sort
    • If the symptoms are violent and the incubation period is very short, intoxication rather than infection should be considered
  • 25. Food Poisoning by Staphylococus aureus Exotoxin
    • Associated with food such as custards, sauces, cream pastries, processed meats, chcken salad, or ham that have been contaminated and then left unrefrigerated for a few hours
    • Toxins do not noticeably alter the food’s taste or smell
    • Heating the food after toxin production may not prevent disease
    • Symptoms: cramping, nausea, vomiting, and diarrhea
    • Rapid recovery- usually within 24 hours
  • 26. Food Poisoning by Bacillus cereus Exotoxin
    • Two exotoxins: one causes diarrheal-type disease, the other cause an emetic disease
    • The type of disease that takes place is influenced by the type of food that is contaminated
    • Emetic form frequently linked to fried rice, especially when cooked and kept warm for long periods of time
    • Diarrheal form associated with cook mats or vegetables that are held at a warm temperature for long periods of time
  • 27. Food Poisoning by Clostridum perfringens Exotoxin
    • Animal flesh and vegetables such as beans that have not been cooked thoroughly enough to destroy endospores
    • Acute abdominal pain, diarrhea, and nausea in 8 to 16 hours
    • Rapid recovery
  • 28.