DISEASES OF THE GASTROINTESTINAL SYSTEM

What are the defenses in the digestive system?

• saliva via lysozyme and IgA

• highly acidic pH in stomach

• mucus and digestive enzymes

• M cells and lymphoid tissue

• microbiota with competitive inhibition

What is the microbiota in the small intestine?

• lactobacillus

What is the microbiota in the colon?

• e. coli

• lactobacillus

• clostridium

• methanogenic archaea

What are the general features of GI diseases?

• diarrhea

• nausea

• vomiting

• fever

• may lead to severe dehydration

What is dysentry?

• mucous

• bloody stools

How does intoxication occur in GI diseases?

• ingestion of a toxin produced by a pathogen

• usually sudden appearance of symptoms

• rarely accompanied with fever

How does infection occur in GI diseases?

• pathogen enters the GI tract and multiplies

• mucosal tissue is penetrated

• often accompanied with fever

• delay in symptoms often occurs while the pathogen invades and multiplies

What is staphylococcal food poisoning?

• intoxication bacterial cause

• caused by toxins from staphylococcus aureus

• food inoculated with bacteria following poor handling

• bacterium is resistant to high osmotic pressure and dessication

• toxins can survive up to 30 minutes of boiling

• onset within 1-6 hours

• recovery within 24 hours

What is shigellosis or bacillary dysentry?

• infection bacterial cause

• causeed by shigella (gram negative rod)

• infects intestinal cell invasin and spreads

• disease can be worsened by shiga toxin

How does shigellosis or bacillary dysentry affect the body?

• leads to tissue damage in colon

• abscess

• dysentry (extreme diarrhea, 20 BM/day)

• possibly kidney failure

How is shigellosis or bacillary dysentry transmitted and resolved?

• fecal contamination from one person to another

• resolves with antibiotic treatment

What is salmonellosis?

• infection bacterial cause

• caused by salmonella enterica (gram negative rod)

• less invasive than shigella

• recovery within a few days via oral rehydration therapy

• transmitted by animals, feces contaminated food, or poorly treated food (e.g. eggs, chicken)

What is escherichia coli gastroenteritis?

• harmless member of microbiota in the colon

• gram negative rod

• 6 e coli strains are pathogenic due to toxins

• transmitted in food and water from feces of human, animals or cattle

• leads to watery diarrhea

What are the two types of e. coli gastroenteritis?

• entero pathogenic e. coli

• entero hemorrhagic e. coli

What is entero pathogenic e. coli?

• EPEC for short

• moderately invasive

• is a toxin

• self limiting

What is entero hemorrhagic e. coli?

• EHEC / STEC for short

• not invasive

• shiga like toxin

• causes bloody diarrhea but mostly self limiting

• extreme cases like O157:H7 can lead to hemolytic uremic syndrome