Among the many cases of H. cinaedi bacteremia, the main symptom is fever. However, various symptoms are important to note. Fever is typically accompanied by arthritis and cellulitis at various sites in the body, which can be regarded either as the primary site of infection of bacteremia or a secondary focus of infection through the bacteremia. In our experience, some patients had a sudden onset of local flat cellulitis (salmon-pink in color) accompanied by fever and an increase in C-reactive protein levels

at various times after orthopedic surgery (range, 8–113 days; mean, 29 days) (Fig. 3) [24]. Cellulitis was often multifocal with no wound infection. Many of these patients had check details been treated for fracture and were immunocompetent. Regarding a new disease relating to H. cinaedi infection, we recently found that H. cinaedi infection is involved in the progression

of atherosclerosis. To investigate the relationship of H. cinaedi infection and atherosclerosis, we first analyzed H. cinaedi infection in the human atherosclerotic aorta by using immunohistochemistry with a specific anti-H. cinaedi antibody. Surprisingly, H. cinaedi antigen was clearly detected see more in atherosclerotic plaques in almost all postmortem human specimens [33], where it was colocalized with macrophages. These observations strongly suggest that H. cinaedi may be closely associated with atherosclerosis in humans. We further investigated the effect of H. cinaedi infection on the development of atherosclerosis and its molecular mechanisms by using Apoeshl atherosclerosis model mice. Apoeshl mice orally infected with H. cinaedi for 8 weeks developed atherosclerosis in the aorta more extensively than uninfected control mice, as confirmed by lipid staining with Oil Red O for atherosclerosis plaques ( Fig. 4(A)) [34]. To the best of our knowledge, this is first evidence of the involvement of H. cinaedi infection in the development of atherosclerosis. The chronic inflammatory response is a widely accepted key mechanism in the progression of atherosclerosis [35] and [36]. Gene expression analysis by real-time reverse transcription-PCR

revealed significantly increased L-gulonolactone oxidase expression of inflammation-related genes, such as inducible nitric oxide synthase, interleukin-1, and Toll-like receptor 4, in aortic tissues of H. cinaedi-infected Apoeshl mice compared with those in uninfected control mice [34]. Mediators responsible for leukocyte adhesion and recruitment in the vascular wall, such as C–C motif chemokine 2 and intercellular adhesion molecule-1, were also upregulated in infected mice. Moreover, nested PCR analysis, which is a highly specific and sensitive detection method for H. cinaedi that we recently developed [37], clearly showed that H. cinaedi DNA and RNA existed in the aorta of infected mice [34]. These findings suggested that oral infection by H.