Combination antimicrobial therapy for Staphylococcus aureus endocarditis in patients addicted to parenteral drugs and in nonaddicts: A prospective study.

Single (nafcillin for 6 weeks) and combined (nafcillin for 6 weeks plus gentamicin for 2 weeks) drug regimens were compared in two separate multicenter prospective randomized trials. Forty-eight parenteral drug addicts and 30 nonaddicts with clinically and bacteriologically documented Staphylococcus aureus endocarditis were studied. In the addicts, combined therapy effected a more rapid mean clinical response (defervescence and normalization of leukocyte count) and a reduced duration of bacteremia in patients with right-sided endocarditis. In the nonaddicts, combined therapy effected more rapid clearance of bacteremia, but was associated with a higher incidence of azotemia. The addition of gentamicin did not alter morbidity or mortality in either group.