Treatment of human brucellosis with doxycycline plus rifampin or doxycycline plus streptomycin. A randomized, double-blind study.

OBJECTIVE: To compare the effectiveness of doxycycline-rifampin (DR) combination therapy with that of the classic doxycycline-streptomycin (DS) combination in patients with brucellosis.

DESIGN: A randomized, double-blind study, with a mean follow-up of 15.7 months.

SETTING: A 1000-bed teaching hospital in Barcelona, Spain.

PATIENTS: Ninety-five patients (68 men and 27 women; mean age, 39 years) diagnosed with brucellosis on the basis of both clinical and serologic findings; 81 of these patients had blood cultures positive for Brucella melitensis.

INTERVENTIONS: Forty-four patients received doxycycline, 100 mg every 12 hours, and rifampin, 15 mg/kg body weight per day in a single morning dose, for 45 days; 51 patients received the same dose of doxycycline for 45 days plus streptomycin, 1 g/d for 15 days.

MAIN OUTCOME MEASURES: Therapeutic failure and relapse during the follow-up period.

RESULTS: The mean time to defervescence was 4.2 days for the DR group and 3.2 days for the DS group (P greater than 0.2). The actuarial probability of therapeutic failure or relapse at 12 months of follow-up (Kaplan-Meier) was 14.4% in the DR group and 5.9% in the DS group (difference, 8.5%; 95% Cl, -4.8% to 21.6%; P greater than 0.2). All three patients with spondylitis in the DR group failed therapy compared with one of four patients in the DS group. Excluding patients with spondylitis, the actuarial failure rate was 4.9% and 4.3% in the DR and DS groups, respectively, at 12 months of follow-up (difference, 0.6%; Cl, -8.1% to 9.4%; P greater than 0.2).

CONCLUSIONS: Doxycycline-rifampin combination therapy for 45 days is as effective as the classic DS combination in most patients with brucellosis; however, DR therapy might be less effective in those patients with spondylitis.