Even a single positive blood culture may matter - A case of prosthetic valve infective endocarditis caused by Corynebacterium kroppenstedtii.

Corynebacterium is a skin commensal bacterium that can contaminate blood cultures. It is however also a rare cause of infective endocarditis (IE). Here we report a case of Corynebacterium kroppenstedtii aortic prosthesis IE in a 76-year-old man where only a single blood culture bottle was positive initially. C. kroppenstedtii is a very rare cause of IE, only reported two times previously. The diagnosis in our case was confirmed by repeated blood culture positivity and eventually by detection of DNA from C. kroppenstedtii on heart valves after valve exchange surgery. At surgery an aortic root abscess was detected and the valve was replaced by a homograft. Recovery was complicated by antibiotic-induced nephrotoxicity and treatment was concluded with moxifloxacin in combination with rifampicin. Recovery was uneventful. This case demonstrates that growth in even a single blood culture bottle may be important in patients with prosthetic heart valves.