Cure of Haemophilus parainfluenzae endocarditis with chloramphenicol

Haemophilus parainfluenzae is an increasingly reported cause of infective endocarditis. In vitro studies have shown this organism to bae almost universally sensitive to chloramphenicol. However, therapy for H parainfluenzae endocarditis with chloramphenicol as a single agent has been disappointing. This has been attributed to the bacteriostatic activity of chloramphenicol, whereas bactericidal agents are essential for cure of infective endocarditis. We successfully treated a patient with H parainfluenzae endocarditis with chloramphenicol alone after in vitro testing showed chloramphenicol to be bactericidal against the organism. When it is documented that chloramphenicol has bactericidal activity against the causative organism, it alone can be effective therapy for H parainfluenzae endocarditis.