Kytococcus schroeteri: a probably underdiagnosed pathogen involved in prosthetic valve endocarditis.

Kytoccoccus schroeteri is an emerging pathogen found mainly in association with prosthetic valve endocarditis. A striking aspect of this species is its resistance to penicillins, including isoxazolylpenicillins, making glycopeptide administration and valve replacement the treatment of choice. We present the case of a 38-year-old female diabetic patient with fever up to 39.1 degrees C for two months. Infection of her prosthetic aortic valve was suspected clinically. Repeated blood cultures revealed growth of K. schroeteri. Transesophageal echocardiography demonstrated a vegetation on the prosthetic aortic valve. Antibiotic treatment with vancomycin, rifampin and gentamicin was started and this regimen led to complete resolution of symptoms and disappearance of the vegetation. It is of particular interest that the patient recovered without further surgical procedures. Since the first description of K. schroeteri in 2002, four cases of endocarditis have been published, suggesting antecedent and continuing underdiagnosis.