PATHOGENS

• Helicobacter pylori: attaches to gastric cells inducing inflammation and cytokine production.
• Culture: if performed, typically is done following treatment failure.
  • Requires endoscopy with gastric biopsy, most frequently from the antrum.
    • The optimal specimen is to place in culture within three hours of collection.
    • Specimen transport can be done in Brucella broth with 20% glycerol.
    • The most frequently employed culture media is Brucella or Columbia agar with 7-10% blood to improve growth in a 5-10% oxygen environment.
    • Cultures are held for up to 10 days due to slow growth.
• Antimicrobial characteristics:
  
  • H. pylori is intrinsically resistant to sulfonamides, trimethoprim and vancomycin.
  • Metronidazole resistance is estimated at 22-39%, 37% commonly cited in U.S. populations.
  • Clarithromycin resistance is ~11-12%; in some studies, up to 24%.
  • Amoxicillin or tetracycline resistance remains less common.