MICROBIOLOGY

• Gram-negative microaerophilic bacteria with a curved bacillary appearance on Gram stain [Fig].
  • Generally oxidase-positive.
  • Growth requirements vary by species:
    • C. jejuni grows optimally at approximately 37–42°C
    • Invasive non-jejuni species may require lower incubation temperatures and specialized microaerobic conditions.
• Turn to separate modules for the following organisms:
  
  • See C. jejuni module for information specific to this species.
    • C. jejuni is the most common Campylobacter species causing human disease, accounting for ~90% of human Campylobacter illness.
  • See the separate H. pylori module for recommendations for this organism.
• Covered in this module:
  • Important non-jejuni Campylobacter human pathogens include C. coli and C. fetus; less commonly, C. upsaliensis, C. lari, C. concisus, and others.
    
    • C. coli is principally enteric.
    • C. fetus is notable for its invasive tendencies, including endovascular infection.
    • Also, this species is a worldwide zoonosis, with C. fetus causing abortion in cattle and sheep.
  • Helicobacter spp. closely related to Campylobacter (e.g., H. pylori, formerly C. pylori)
    • H. cinaedi, H. fennelliae, H. pullorum, and H. canadensis have all been described as causing human illness.
    • H. cinaedi is especially associated with bacteremia and recurrent cellulitis, frequently in immunocompromised individuals.
      • Other Helicobacter spp. do not have a clearly established set of presentations because they are rare.