Haemophilus parainfluenzasEndocarditis

Three cases of Haemophilus parainfluenzae endocarditis in previously healthy patients were diagnosed in one six-month period. The presenting clinical picture was not typical of endocarditis. The initial physical examination and laboratory studies were normal except for hectic fever. Blood cultures were negative until subculture to chocolate agar and incubation in CO2 was done. Antibiotic susceptibility testing in vitro revealed that the penicillins, cephalothin, and gentamicin were active against the organisms isolated. It is recommended that blood cultures be subcultured to chocolate agar and incubated in CO2 whenever endocarditis is expected and the initial cultures are negative. Two of the patients were treated with ampicillin; the third patient received ampicillin, streptomycin and tetracycline. All patients were treated for six weeks and were cured.