Lecture 14 Flashcards
(44 cards)
Axenic organs of the GI tract
Esophagus, stomach, and duodenum are almost free of microbes
- peristalsis prevents long term colonization of GI tract
Plaque (formation and causative agent)
- Streptococcus mutans (initial colonizer) will attach to surface of tooth
- other bacteria come and attach to already attached bacteria using lectins (lectins bind to sugar, act as adhesin)
Dextran
- enzyme that uses sugar to:
- create biofilm for plaque
- fermentation produces acid
3 things required for dental caries
- Buildup of plaque
- place for bacteria to persist - Dietary sucrose
- food for bacteria - Acidogenic bacteria
- by-product of fermentation that deteriorates teeth
Cavities prevention
Regular dental hygiene
Block binding of bacteria/ formation of plaque
- -Use polymers to cover teeth
- -Use antibacterial coating for teeth
Fluoride
- -Fluoride works by displacing the hydroxyl ions in hydroxyapatite
- -Reduces the solubility of tooth enamel
Periodontal Disease (causative agent)
Porphyromonas gingivalis, Leptotrichia buccalis (Gram-negative rods) Treponema vincentii (Gram-negative spirochete)
- not flossing (b/c these bacteria colonize the anaerobic pockets between teeth and gums)
Staphylococcal Food Poisoning (causative agent)
Staphylococcus aureus, G (+) cocci
Staphylococcal Food Poisoning (transmission)
- Part of normal flora in nose, on skin
- Introduced to food by sneezing, coughing, contact w/ boils or abscesses
Staphylococcal Food Poisoning (symptoms)
- very fast acting, symptoms show within 1-6 hours
- abdominal cramps, nausea, vomiting, diarrhea
Staphylococcal Food Poisoning (pathogenixcity)
- enterotoxins
- resistant to high temp and low pH
- able to survive in stomach and pass through
Staphylococcus aureus (identification)
mannitol salt agar
Cholera (causative agnet)
Vibrio cholerae
Gram-negative curved rod
Cholera (transmission)
Water or food (raw oysters) contaminated with feces
- usually transmitted through human feces
- must consume high dosage b/c most die in stomach
- in high dosage, a few are able to pass through stomach and colonize intestines
Cholera (symptoms)
- rice water stool” Diarrhea (1L/hour) –> good diagnostic factor
- Dehydration, cramps
- Blood thickens (from lack of water), resulting in shock and eventually, coma
Cholera (pathogenicity/virulence factor)
- Cholera toxin stimulates fluid loss (diarrhea)
How does cholera toxin functions?
- this is an AB toxin
- B triggers endocytosis
- A triggers cAMP that pump electrolytes out of the cell and into lumen
- water follows salts (due to osmosis)
- b/c there is a hypotonic solution outside of cell
Cholera (treatment)
- replenish lost water and salts
- usually with gatorade
- antibiotics wont work well b/c everything is getting pumped out due to cholera toxin
Salmonellosis (causative agent)
- Salmonella enterica G (-) rods
Salmonellosis (transmission)
- uncooked poultry
- chicken, eggs
- cutting board (where chicken was then veggies were cut)
Salmonellosis (symptoms)
- incubation 1-2 days
- Nausea, fever, vomiting, diarrhea (possible dehydration), abdominal cramps, possible intestinal ulceration
Salmonellosis (pathogenicity/virulence factor)
- type III secretion system (T3SS)
- inject toxins into cells, and triggering endocytosis
- pathogen is now able to replicate in cell (kills cell and escapes, which causes symptoms)
Salmonellosis (Diagnosis/treatment)
- diagnosed by stool sample, and symptoms
- treated with replacing fluid loss with with water and electrolytes
Typhoid Fever (causative agent)
Salmonella enterica serotype Typhi, G (-) rod
- tough pathogen, able to survive harsh environment, need a small dose for infection
Typhoid Fever (pathogenicity)
Same as salmonellosis but…
- Blood invasion
- pathogen gets into blood and makes its way to other organs (gal bladder)
- A2B5 toxin
- causes: fever and delirium (typhos), rose spots on abdomen (hemorrhaging)
