EXAM #1: BACTERIAL INFECTIONS OF THE GI TRACT Flashcards
What are the symptoms of Botulism poisoning?
1) Dizziness
2) Dry mouth
3) Blurred vision
4) Abd. sx
5) Progressive paralysis
What causes Botulism?
Improperly canned (non-acidic food)
When do the symptoms of Botulism start?
12-36 hours after ingestion
Is fever present in Botulinism?
No–only ingested toxin, NOT whole pathogen
What organism causes Botulinism?
C. botulinum
List the characteristics of C. botulismsm.
Gram positive
Spore forming
Rod-shaped
Anaerobic
What kind of toxin is the C. botulinum toxin?
A-B Bacterial toxin
What is the MOA of the C. Botulinum toxin?
1) B portion attaches to receptors on motor nerve endings
2) A portion enters nerve cell
3) Toxin blocks release of ACh
What causes Floppy Baby Syndrome?
C. Botulinum spore ingestion
What are the symptoms of Floppy Baby Syndrome?
Constipation followed by generalized paralysis
Where are C. botulinum spores and toxins identifiable in Floppy Baby Syndrome?
Feces
How is Botulsim treated?
Antitoxin administration
What is a major adverse effect of Botulism antitoxin administration?
Serum sickness
What are the characteristics of Clostridium difficile?
Gram positive
Spore forming
Rod-shaped
Anaerobic
What does Clostridium difficile cause?
Antibiotic associated pseudomembranous colitis
What is the most common cause of nosocomial diarrhea?
Clostridium difficile
How is Clostridium difficile transmitted?
Fecal-oral
What antibiotic was the first abx to cause pseudomembranous colitis?
Clindamycin
What are the most common causes of pseudomembranous colitis today?
2nd and 3rd generation cephalosporins (only b/c they are the most frequently used)
What are pseudomembranes?
white-yellow plaques on the colonic mucosa
What is a severe complication of Clostridium difficile infection?
Toxic megacolon
How do you tell the difference between adverse diarrhea with abx administration vs. Clostridium difficile?
Clostridium difficile toxin present in the stool
How is Clostridium difficile treated?
1) Withdraw antibiotic
2) Oral metronidazole* or vancomycin
3) Fluid replacement
*Preferred
What is Shigellosis?
Dysentery i.e. bloody diarrhea
List the characteristics of Shigella dysenteriae.
Gram negative
Rods
Non-lactose fermenting
How does Shigella dysenteriae appear on MacConkey agar?
Colorless b/c non-lactose fermenting
How is Shigella dysenteriae distinguished from Salmonella?
1) Do NOT produce H2S
2) Non-glucose fermenting
3) Non-motile
What infective dose is required for Shigella dysenteriae infection? How does this compare to Salmonella?
Shigella dysenteriae= low
Salmonella= high
What type of diarrhea is seen with Shigella dysenteriae?
Bloody diarrhea
What is the typical symptom progression in Shigella dysenteriae infection?
1) Fever, abdominal cramping and diarrhea
- Watery diarrhea at first
- Bloody/ mucousy diarrhea
What strain of Shigella causes a much milder disease than Shigella dysenteriae?
Shigella sonnei
What strain of Shigella is most common in the US?
Shigella sonnei