Prosthetic valve endocarditis due to Haemophilus parainfluenzae biotype II.

Haemophilus parainfluenzae endocarditis is characterized by great variation in the acuteness of presentation, difficulty in isolation of the pathogen, a 50% to 60% incidence of major arterial emboli, and variability of response to therapy. Prosthetic valve endocarditis (PVE) due to H parainfluenzae biotype II occurred in a 14-year-old girl with congenital heart disease and a Starr-Edwards mitral valve prosthesis. Management was complicated by a prolonged culture-negative period (eight days), intermittent bacteremia (only five of 15 positive blood cultures), an embolus to the right femoral artery, progressive congestive heart failure, and urgent prosthestic valve replacement. Cure was achieved with 44 days of ampicillin sodium-gentamicin sulfate therapy monitored by serum bactericidal titers.