Taniguchi T, Saeki Y, Okayama A et al.
Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
Microbiology and immunology. Mar 2017.
Although Helicobacter cinaedi was initially considered an opportunistic pathogen in immunocompromised patients, it was later shown to also infect immunocompetent patients and even healthy individuals. Sporadic bacteremia due to H. cinaedi has been frequently reported, but it remains unclear whether the bacterium can be translocated after passage through the intestinal mucosa. In the present study, we developed a preclinical small animal model that can faithfully reproduce H. cinaedi infection in humans. Balb/c male mice were orally inoculated with a single dose of 6.8 x 10(7) colony forming unit (cfu) of a human clinical H. cinaedi strain. The organism persistently colonized the intestinal tract of the mice, particularly the cecum and colon, for at least 56 days, and the bacteria were excreted in feces. Although inoculated bacteria were recovered from the spleen, liver, kidney, lung, bladder, and mesenteric lymph nodes during the first 2 weeks of bacteremia, the organism was not isolated from these organs after 4 weeks, suggesting that complement- and antibody-mediated serum sensitivity may account for the relatively low frequency of systemic infection. However, H. cinaedi was isolated from biceps femoris, triceps branchii, latissimus dorsi, and trapezius muscles beyond 2 weeks after infection even after production of specific anti-H. cinaedi Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies. Our present findings suggest that experimental infection of Balb/c mice with H. cinaedi might be a useful model for further studies of H. cinaedi pathogenesis, prophylaxis, or therapeutic interventions in vivo.