Campylobacter and Helicobacter Pylori Notes

Campylobacter Species

  • C. jejuni: Most common cause of bacterial gastroenteritis in the US.

    • Worldwide distribution.

  • C. coli: Responsible for 2-5% of Campylobacter gastroenteritis.

  • C. upsaliensis: Important cause of gastroenteritis, difficult to isolate.

  • C. fetus: Causes gastritis and is associated with spontaneous abortions and extra-intestinal diseases.

  • Growth Requirements:

    • Need 10% CO2, reduced O2, and a temperature of 42°C.
    • Enriched isolation medium is necessary for cultivation.

Campylobacter Enteritis

  • Most cases occur during summer or early fall, often due to consuming undercooked poultry.
    • Nearly 50% of retail chicken is infected, hence the need for thorough cooking.

Symptoms of Campylobacter Enteritis

  • Range from asymptomatic to severe illness.

    • Symptoms include fever, cramping, and diarrhea (which may be bloody), typically onset 2-5 days post-consumption.
    • Duration is usually self-limiting, lasting 2-10 days.

  • Epidemiology: Estimated 2 million cases per year in the US.

    • C. jejuni is linked to Guillain-Barré Syndrome, a severe autoimmune disorder that can cause ascending paralysis.

Helicobacter pylori

  • Present in gastric biopsies of both animals and humans.
    • Isolated over 100 years ago but confirmed as a cause of stomach ulcers only in 1982.
    • Initially considered a chronic issue; most ulcers are now treatable with antibiotics.

Symptoms of Gastric Ulcers

  • Acute gastritis develops within two weeks of infection, causing abdominal pain, nausea, and vomiting.

    • Chronic conditions develop in most infected individuals.

  • Linked with gastric cancer:

    • Study showed that antibiotics targeting H. pylori reduced the risk of secondary cancers by two-thirds after gastric surgery.

Diagnosis of an Ulcer

  • Methods:
    • Gastric biopsy with urease test (H. pylori is urease positive).
    • Urea breath test.
    • Growth in lab under enriched medium at 37°C with 10% CO2 for 5-7 days.
    • Other methods include histology and serology.

Formation of Peptic Ulcer

  • H. pylori attaches to stomach epithelial cells, proliferates, and triggers inflammation through exotoxins, leading to cell death and mucus layer thinning.
  • Process:
    1. Bacteria invade mucus and attach to gastric epithelial cells.
    2. Toxins and inflammation thin the mucus layer.
    3. Gastric acid damages epithelial cells and underlying tissues, forming an ulcer.

Treatment of H. pylori

  • Multi-drug regimen including metronidazole or clarithromycin combined with antacids is commonly used.
    • Treatment duration: 7-14 days.
    • Emerging resistance to medications is noted.

Importance of Vitamin B6 in H. pylori

  • Research indicates that H. pylori requires Vitamin B6 for the establishment and maintenance of chronic infections.
    • Potential for developing new antibiotics based on this finding.

H. pylori and Its Effects on Other Conditions

  • In children (ages 3-13):
    • Testing positive for H. pylori linked to lower likelihood of asthma (59% less likely) and hay fever (69% less likely).
    • Children with inflammatory bowel disease less often test positive for H. pylori.
  • Considerations of long-term risks vs. benefits of H. pylori status:
    • Possible links to the development of peptic ulcers and gastric cancer later in life.