Intoxications And Infections Of The Intestines Flashcards
What are the characteristics of food intoxication?
Follow ingestion of food Short incubation times (2-12 hours) Not an infection No fever No fecal leukocytes Rapid onset
What are the etiologies of food intoxication?
Staphylococcus aureus-second most common cause
Bacillus cereus
Clostridium perfringens type A is the most common
What are the manifestations of food poisoning due to S.aureus?
After consumption of highly processed food (potato salad, creme puffs)
Projectile vomiting
Little or no diarrhea
No fever
S aureus has 8 enterotoxins that are heat stable
What are the manifestations of food poisoning due to B.cereus?
Type 1 enterotoxin -depsipeptide cereulide -is heat stable
Causes nausea, vomiting, little if any diarrhea
Acquired in starch rich food like fried rice
Type 2 enterotoxin-hemolysin BL and non hemolytic-is heat labile
Causes profuse diarrhea little if any vomiting
Acquired in protein rich food (meat, milk, fish)
What are the manifestations of food poisoning due to C. Perfringens?
Heat labile enterotoxins
Abdominal cramps and diarrhea
Acquired through meat products, gravy
In severe cases can cause necrotizing enteritis
What are the etiologies of viral gastroenteritis?
Rotavirus-second most common cause in under 2
Norovirus- most common cause
Sapovirus- like norovirus but less common
Astrovirus- vomiting uncommon
Adenovirus- like rotavirus in older infants, can cause intussusception
What is a feature observed in viral gastroenteritis but not in food intoxication?
Low grade fever
What is the pathology and treatment of viral gastroenteritis?
Virus infect cells in the small intestine
Decrease in absorption of sodium and water from bowel leads to watery diarrhea
Activation of serotonin receptors causes vomiting
Treat with fluid and electrolytes by mouth or IV for shock patients
Antiemetics and antidiarrheals for adults but not recommended for children
What are the etiologies of bacterial gastroenteritis non inflammatory?
E. Coli Vibrio parahaemolyticus Vibrio cholerae There is no invasion of small intestine and vomiting is less common compare to viral gastroenteritis No fecal leukocytes
What are the 3 types of E.coli that causes non inflammatory bacterial gastroenteritis?
ETEC- Infantile diarrhea and most common cause of travelers diarrhea-LT toxin (heat labile), ST toxin (heat stable)
EAEC- more persistent travelers diarrhea- heat stable toxin
EPEC-mild diarrhea in infants less than 6 months old, no toxin
What are the characteristics of bacterial gastroenteritis caused by vibrio parahaemolyticus?
V. Parahaemolyticus is a curve oxidase positive gram negative rod and halophile
Causes explosive diarrhea to cholera like illness
Headache, abdominal cramps, nausea, vomiting, low grade fever
Acquired from eating raw shellfish
Most common cause of shellfish associated gastroenteritis in US
What is the pathology of V.parahaemolyticus and diagnosis?
Thermostable Kanagawa hemolysin induces chloride ion secretion
Green colonies on TCBS agar
Beta hemolytic on human RBC agar plates but not on sheep RBC agar
What are the symptoms of non inflammatory bacterial gastroenteritis caused by vibrio cholera?
Abrupt onset of watery diarrhea
Rice water stools
Vomiting may occur
No fever
Due to contaminated water (shellfish, crabs)
Related to foreign travel
If in the USA acquired during warm months , crabs from gulf coast
What is the pathology of V.cholera?
O1 and O139 serotypes cause severe disease
Large dose of cells is needed for disease
Attach to microvilli
No invasion
Produce cholera toxin
Yellow colonies on TCBS agar
What are the parasitic gastroenteritis?
Giardiasis- most common
Cyclosporiasis
Cryptosporidiosis- chronic problem in I/C patients
