Propionibacterium acnes prosthetic valve endocarditis with abscess formation: a case report

BACKGROUND Endocarditis due to Propionibacterium acnes is a rare disease. Scant data on treatment of these infections is available and is based on case reports only. If the disease is complicated by abscess formation, surgical intervention combined with an antibiotic therapy might improve clinical outcome. In some cases, cardiac surgeons are reluctant to perform surgery, since they consider the intervention as high risk. Therefore, a conservative therapy is required, with little, if any evidence to choose the optimal antibiotic. We report the first case of a successfully treated patient with P. acnes prosthetic valve endocarditis without surgery. CASE PRESENTATION We report the case of a 29-year-old patient with a prosthetic valve endocarditis and composite graft infection with abscess formation of the left ventricular outflow tract due to P. acnes. Since cardiac surgery was considered as high risk, the patient was treated intravenously with ceftriaxone 2 g qd and rifampin 600 mg bid for 7 weeks and was switched to an oral therapy with levofloxacin 500 mg bid and rifampin 600 mg bid for an additional 6 months. Two sets of blood cultures collected six weeks after completion of treatment remained negative. The patient is considered to be cured based on absence of clinical signs and symptoms, normal laboratory parameters, negative radiology scans and negative blood cultures, determined at site visits over two years after completion of treatment. CONCLUSION To our knowledge, this is the first successfully managed patient with P. acnes prosthetic valve endocarditis with abscess formation of the left ventricular outflow tract who was treated with antibiotics alone without a surgical intervention. A six month treatment with a rifampin and levofloxacin combination was chosen, based on the excellent activity against stationary-phase and adherent bacteria.