Bacterial Infections of the GI Tract Flashcards
Non-inflammatory diarrhea vs inflammatory diarrhea
Non-inflammatory (e.coli) - ingestion of toxin causes elevations in cAMP and watery diarrhea.
Inflammatory (Shigella) - organism colonizes the intestine, cytotoxins cause inflammation, which causes diarrhea.
What type of disease is cholera?
Toxin-mediated. Caused by vibrio cholerae.
Vibrio cholerae characteristics
Curved/straight bacilli. Gram negative, 150o serotypes, but only 1 and 139 are cholerogenic.
Where does vibrio cholerae live?
Aquatic environments
Clinical symptoms of cholera
Devastating watery diarrhea, vomiting
Main defense against cholera?
Gastric acidity
How is cholera toxin created?
Lysogenic phage integrates into genome, activated when vibrio is in right temperature and sugar concentration.
TCP pilus
On vibrio cholerae, important for attachment and colonization of vili.
What type of toxin is choleratoxin?
AB toxin. 2 types of A’s. Increases cAMP in body.
Therapy for choleratoxin?
Rehydration
Shigella appearance
Non-lactose fermenting gram negative rods
What does shigella cause?
Dysentery
What are the symptoms of dysentery?
Small volume, bloody diarrhea. Abdominal cramps/pain, tenesmus (straining).
What is the shigella reservoir?
Humans, transmitted from person to person, common in children.
What part of shigella dysenteriae causes dysentery?
Shigatoxin shuts down cell and causes death.
Salmonella species characteristics
Gram negative rods, facultatively anaerobic, motile, no fermentation of lactose/sucrose
Which salmonella causes enteritis?
S. typhimurium
Which salmonella causes typhoid fever?
S. typhi
Salmonella gastroenteritis symptoms
N/V within 48 hours, urgency, diarrhea can vary.
Typhoid fever.
Systemic disease with multiorgan disfunction. Prolonged fever, sustained bloodstream infection. Passes from stool to blood
How can you get a non-thyphoidal salmonella infection?
Agricultural products like eggs, processed food like dairy, domestic animals like iguanas.
How is salmonella pathogenic
Survives within macrophages and other non-phagocytic cells, encapsulated
How can you get a campylobacter infection?
Handling chicken. Little person to person transmission.
What is the worst case scenario w/campylobacter?
Guillain Barre syndrome. Most of the time the disease is self-limiting.
Heliobacter Pylori
Causes gastric ulcers, not diarrhea. CLASS 1 CARCINOGEN (gastric adenocarcinoma and MALT lymphoma).
Antibiotic treatment for vibrio, campylobacter, salmonella, shigella
Fluoroquinolones, 3rd generation cephalosporins, macrolides. Frequently resistant to amoxicillin, TMPSMZ and 1st generations cephs.
