L33-35: Bacterial Infections of the GI Tract Flashcards
Diarrhea
Passage of 3+ loose/liquid stools per day, usually result in disease of small intestine
What are the host defenses that the GI tract can use to prevent disease?
Continuous epithelium, mucus (but sometimes triggers virulence), low pH, gut motility, shedding of epithelium, bile, secretory IgA, normal microbiota
Gastritis
Inflammation of the stomach
Gastroenteritis
Inflammation of stomach and intestines, characterized by nausea, vomiting, diarrhea, and abdominal discomfort/pain
Dysentery
Inflammatory disorder of the GI tract often causing diarrhea with blood/pus, pain, fever, abdominal cramps – normally associated with large intestine
Enteritis
Inflammation of the intestines, especially small intestine
Enterocolitis
Inflammation of the mucosa of small and large intestine
Colitis
Inflammation of the large intestine, specifically the colon
Inflammatory bacteria characteristics
Cause damage to the intestine through inflammation, more likely to see fecal occult/leukocytes or visible blood
Inflammatory bacteria types
Salmonella spp., Campylobacter jejuni, C. diff (severe cases), EHEC, EIEC, Shigella spp., Vibrio parahaemolyticus, Yersinia enterocolitica
Non-inflammatory bacteria characteristics
Pass through the intestine or adhere to intestinal epithelium – either don’t produce toxins or non-cytotoxic toxin
Non-inflammatory bacteria types
EPEC, ETEC, Vibrio cholerae, Listeria monocytogenes
Which bacteria cause bloody diarrhea? (sometimes or often)
EHEC, Campylobacter jejuni, Shigella spp., Yersinia enterocolitica, EIEC, C. diff, Vibrio parahaemolyticus
Which bacteria cause watery diarrhea? (rarely blood)
EPEC, ETEC, food poisoning, Clostridium perfringens, Bacillus cereus, Vibrio cholerae, Salmonella spp., Listeria monocytogenes
Which bacteria cause symptoms 1-8 hrs after ingestion and what is their mechanism?
Preformed toxin – S. aureus, Bacillus cereus (emetic), C. botulinum
Which bacteria cause symptoms 8-16 hrs after ingestion and what is their mechanism?
Production of toxin after ingestion – B. cereus (diarrheal), C. perfringens, C. botulinum
Which bacteria cause symptoms 16+ hrs after ingestion and what is their mechanism?
Adherence, growth and virulence factor production – Shigella, Salmonella, Listeria monocytogenes, all E. coli species, Campylobacter, Vibrio species
2 types of bacterial food poisoning
- Toxins produced before food is eaten
2. Large number of spores that germinate in intestine and produce toxins
Symptoms of bacterial food poisoning
Diarrhea, vomiting, but NO FEVER
4 main causes of bacterial food poisoning
S. aureus, C. botulinum, C. perfringens, Bacillus cereus
S. aureus in food poisoning
Preformed toxin, causes severe vomiting, diarrhea, and abdominal pain in 1-8 hrs – toxin is HEAT-STABLE (not well understood) – supportive treatment
Disease process of C. botulinum
Causes botulism, mediated by botulism toxin – early stage: vomiting, diarrhea, abdominal pain 1-16 hrs later, late stage: flaccid paralysis leading to progressive muscle weakness and respiratory arrest
Mechanism of infection of C. botulinum
Ingestion of preformed toxin or large number of spores
How does the botulism toxin work?
Acts at neuromuscular junction and interferes with signaling at synapses – if patient survives there can be lingering weakness and dyspnea up to a year later