Propionibacterium acnes endocarditis on an annuloplasty ring in an adolescent boy.

Propionibacterium acnes, a constituent of the human cutaneous flora, infected both the native mitral valve and a Carpentier mitral annuloplasty ring in an adolescent patient. In the case of culture negative endocarditis, the incubation period of blood cultures should be prolonged to identify this pathogen.