Gemella endocarditis: consider the colon.

Gemella species, including Gemella morbillorum, are part of the normal flora of the human oropharynx, upper respiratory tract and gastrointestinal tract. Differentiation of Gemella from viridans streptococci in the laboratory may be difficult. Although uncommonly pathogenic, they have been implicated in a variety of human infections, most notably infective endocarditis. Dental instrumentation appears to be the usual source of infection. The case is reported of Gemella morbillorum native valve endocarditis, which was associated with an underlying colonic carcinoma. An association with colonic neoplasm has been described in three previous cases of endocarditis attributed to Gemella. It is well documented that Streptococcus bovis endocarditis may occur in the setting of colonic neoplasia. It is suggested that colonic investigation should be considered in patients with Gemella endocarditis, in whom no other source is apparent.