Peptostreptococcus species: an unusual cause of infective endocarditis.

Peptostreptococcus species are part of the normal flora of human mucocutaneous surfaces. They account for 30% of anaerobes isolated from clinical sources, and are involved in a wide variety of clinically significant infections. Peptostreptococcus magnus is the species most frequently isolated from clinical specimens as well as from normally sterile sites in pure culture. Rarely have these organisms been reported as causes of endocarditis involving native and prosthetic valves, and very little is known about the appropriate therapy for these infections. We report a case of native valve endocarditis caused by Peptostreptococcus species, and provide a review of the literature on infective endocarditis caused by these organisms.