32- Campylobacter and Helicobacter Flashcards
Campylobacter- diseases
Gastroenteritis (C. jejuni), Guillian-Barré syndrome (C. jejuni and C. upsaliensis) Reactive arthritis
Campylobacter- virulence factors
Contains adhesins, cytotoxic enzymes and enterotoxins but roles are poorly defined.
Campylobacter- clinical presentation
Gastroenteritis: diarrhea, fever, abdominal pain, grossly bloody stools, mimicing acute appendicitis, bacteremia. Self-limiting. Guillian-Barre: symmetrical weakness over several days and recovery over months. Reactive Arthritis: painful joint swellings that may last for weeks to a year.
Campylobacter-epidemiology
Zoonic infection: undercooked poultry
Campylobacter-pathogenesis
Gastroenteritis: Histologic damage to nthe mucosal surfaces of the jejunum (think C. jejuni = jenunum damage) Guillian-Barre: autoimmune disorder, antigenic cross-reactivity of capylobacter and nerve gangliosides Reactive Arthritis: autoimmune reaction at joints
Campylobacter-laboratory features
Shape: S-shaped rods, “gull wings” Gram stain: negative Other features: microaerobic, C. jejuni grows best at 42 degrees, polar flagella, oxidase +, catalase +
Helicobacter-diseases
Gastric ulcer, gastritis, MALT lymphoma
Helicobacter- virulence factors
Urease
Helicobacter-clinical presentation
Gastritis- nausea, vomiting, hypochlorydria (decreased stomach acid). Can evolve into gastric or duodonenal ulcers
Helicobacter-epidemiology
fecal-oral
Helicobacter-pathogenesis
Urease converts urea into NH3 and CO2, thereby raising the pH of the stomach by buffering acid production. It also blocks acid production by bacterial acid-inhibitory protein.
Helicobacter-lab features
Shape: spiral Gram Stain: negative Other features: no culture, grow at 37 degrees (body temp). Diagnosis: biopsy for bacterial urease, urease breath test using isotopically labeled urea solution
