Gut Microbiota + Bacterial Gastroenteritis Flashcards
The proximal gut is relatively sterile.
List 4 benefits of the gut microbiome
- Harmful bacteria can’t compete for nutrients
- Microbiome produced antimicrobials
- Helps develop newborn’s immune system
- Produce certain nutrients (Vit K)
Colonic bacteria produce certain Short Chain Fatty Acids (SCFAs)
Name 3 and state their functions
Butyrate;
- Energy source for colonocytes, helps regulate gut environment
Acetate;
- Involved in cholesterol metabolism
Propionate;
- Helps regulate satiety
Compare Pro and Prebiotics
Pro: Live bacteria and Yeast put in food
Pre: Food for microbiota
Suggest an infection that can be treated with Faecal Microbiota Transplant
C Difficile infection (No side effects, up to 90% success)
Crohn’s and IBD symptoms as well possibly
List 4 criteria for being eligible to donate Faeces for a Faecal Microbiota Transplant
- 10-25 year olds
- 3 months without use of Antibiotics, Laxatives, Diet pills
- No GI disease
- Completely screened
List 4 gram negative rods that can cause Gastroenteritis
Which ones can produce bloody diarrhoea?
How long do they generally last?
- Salmonella (Watery, Days)
- Campylobacter (Can be bloody, Weeks)
- Shigella (Can be bloody, A week)
- Enterotoxigenic E-Coli (Watery, Days)
List 1 gram positive bacteria that can cause Gastroenteritis
C. difficile
List 5 symptoms of Salmonella
Spread by ingesting contaminated food/ water
(Self limiting in healthy people, only need supportive treatment)
- Nausea + Vomiting
- Diarrhoea (Mostly non bloody)
- Fever
- Ab cramping
Describe the pathophysiology of Salmonella once in the gut
- Enters small intestinal cells by Endocytosis
- Moves to Submucosna, is taken up by macrophages
- Transferred to RES, where it multiplies Intracellularly
- Causes lymphoid hyperplasia + hypertrophy
- Re enters bowel from liver
Describe Campylobacter
Spiral organism
- Often found in poultry
- Needs to multiply in host before symptoms appear
- Generally self-limiting (days to weeks)
- Releases a cytotoxin
List 3 symptoms of Campylobacter infection
What is the treatment?
- Fever
- Ab cramping
- Diarrhoea (Can be bloody)
- Usually supportive, Fluid/ electrolyte replacement
- Consider antibiotics if bloody diarrhoea
Describe Shigella
- Causes Shigellosis, a dysentery commonly affecting young children
- Spread from infected stools
- Only small dose needed to infect
- Usually resolves in a week, if healthy
What are 2 symptoms of Shigella infection?
- Ab cramping
- Diarrhoea with Blood + Mucus
Outline the pathophysiology of Shigella infection
- Enters large intestinal cells by Endocytosis
- Escapes vesicles and multiplies in cells, away from macrophages
- Invades neighbouring cells, forming a Mucosal Abscess as cells die (mucus released)
Describe Enterotoxigenic E-Coli (Commonly causes Travellers Diarrhoea)
Describe its pathophysiology
- Commensal of Colon
- Faecal-oral spread via contaminated water
- Adheres to enterocytes
- Produces Enterotoxins, which cause Cl-hypersecretion
- H2O leaves cells-> Gut lumen (Follows Na which follows Cl)
