Experimental infection of pig-tailed macaques (Macaca nemestrina) with Campylobacter cinaedi and Campylobacter fennelliae.

Campylobacter cinaedi and C. fennelliae have been associated with proctocolitis, bacteremia, and asymptomatic rectal infection, primarily in homosexual men. To more directly assess the pathogenic role of these organisms, we studied their disease-producing potential in 12- to 25-day-old pig-tailed macaques (Macaca nemestrina). Four infant monkeys were challenged with 10(8) to 10(9) C. cinaedi, three were challenged with C. fennelliae, two were challenged with C. jejuni, and one received no microorganisms. Watery or loose stools without associated fever or fecal leukocytes developed 3 to 7 days postinoculation in all of the animals given C. cinaedi, C. fennelliae, and C. jejuni, but not in the control animal. Stool cultures were simultaneously positive and remained so in the animals challenged with C. cinaedi or C. fennelliae for 3 weeks after inoculation despite the resolution of clinical illness. All of the animals challenged with C. cinaedi and C. fennelliae became bacteremic, and three had clinical evidence of septicemia. Histopathologic evaluation of rectal biopsies (five animals) and necropsy (one animal) showed no evidence of mucosal disruption. Specific immunoglobulin M and immunoglobulin G antibody responses occurred in all of the animals challenged with C. cinaedi and C. fennelliae, as determined by enzyme-linked immunosorbent assay and immunoblotting. We conclude that C. cinaedi and C. fennelliae consistently produce a diarrheal illness accompanied by bacteremia and followed by prolonged gastrointestinal colonization in M. nemestrina.