Random fun facts from the gut flora lecture Flashcards
What is a common characteristic among gut normal flora?
90-95% are anaerobic!
What are some important roles of normal flora?
prevent pathogenic bacteria from multiplying (good example is c. diff w. antibiotic therapy)
helps develop immune functions
stimulates development of gut mucosa
bac help with vitamins etc.
How do bacteria help with immune development?
normal flora –> increase number of lymphocytes and plasma cells in the lamina propria
increase the size of peyers patches etc
increase production of IgA and IgG
What vitamins are produced by normal flora?
vit. k, B9, B12, B2, B7, B1, B3, pyridoxine
What is it about the normal microbiome that helps prevent C. diff infection?
DIVERSITY!… a study showed that w/ each bout of C. diff the microbiome became less diverse w/ fewer species predominating causing and increased amount of c diff infections
Diarrhea vs. dysentery?
Diarrhea = increase in stool frequency, and or fluidity w/ large volume stools
dysentery = painful, frequent, small volume stools w/ fecal leukocytes and blood
How did the prof split up diarrhea?
1) secretory (non-inflammatory)
2) exudative (inflammatory)
3) systemic (enteric fever)
What is non-inflammatory butt pee, where would i find it, what kind of stool and what are examples?
caused by a toxin (NO invasion)
typically effects small intestine
causes a watery butt pee
stool exam shows NO leukocytes
*examples = S. Aureus toxin and Vibrio cholerae
What is inflammatory butt pee, where would i find it, what kind of stool and what are examples of bugs that cause it?
Mechanism = Invasion/ cytotoxin
location = colon
Typically causes dysentery!
stool exam would show leukocytes and occasionally RBCs
*shigella, EHEC, salmonella enteriditis, campylobacter jejuni
What about systemic disease butt pee?
mechanism = penetrate mesenteric lymph nodes (peyers patches), GI tract serves as port of entry
typically in the distal small intestine
examples = salmonella typhi (typhoid fever), and yersinia enterocolitica
What is buzzword for very acute onset, food poisoning by S. aureus?
MAYO (its short for mayonnaise).. S. Aureus makes pre-formed spores… onset after eating = 1-5 hours and usually for less that 24 hours duration
What is the bacteria or toxin responsible for food poisoning after eating rice that is cooked then kept warm (ie like at a buffet)
bacillus cereus!!! (produces a heat stable toxin)
What is the 2 stage model for EPEC adhesion?
stage 1 = microcolony formation by bundle forming pili
stage 2:
-“intimate” attachment mediated by OMP (intimin) and receptor (Tir)…
-Tir is actually a bacterial protein that is translocated to the epithelial cells by a type III secretion system
-bacteria attach to the enterocyte membrane, use t3SS to inject other effectors, disrupt host cell apical cytoskeleton and form pedestals
Consequence = WATERY diarrhea in inftants typically…
