Campylobacter fetus ss. Jejuni, a newly recognized enteric pathogen: morphology and intestinal colonization

Campylobacter fetus ss. jejuni has recently been recognized as a frequent enteric pathogen of man. Although long known as a significant pathogen of domestic animals, little is known regarding mechanisms of colonization and pathogenesis. In an effort to study the colonization and morphology of this organism, we used scanning electron microscopy to examine ilea and colons from mice in which a human isolate of C. fetus ss. jejuni had been inoculated. When inoculated into the ileum of the mice, a transient colonization was observed by 24 hours and had disappeared by 48 hours. Colonization of the colon first appeared at 48 hours and persisted at least three weeks. When inoculated directly into the colon, colonization appeared within 24 hours in the colon and persisted at least 16 days. Severe colonic necrosis and mucosal degeneration were observed in colons only in those mice which were inoculated via the colon. In the infected colons, the C. fetus ss. jejuni organisms were enmeshed in a fibrous network which may play a role in the attachment of bacteria to the mucosal surface. Differences between the morphology of C. fetus ss. jejuni in the mouse model and that found in pure culture were observed and may represent distinct tissue and culture phases of growth.