Brucellosis-doxycycline therapy: data from a multicenter randomized trial

Brucellosis is a common zoonotic infection. The acute phase is manifested by the occurrence of a fever of unclear origin, accompanied by non-specific symptoms. Typically, treatment for acute uncomplicated brucellosis without focal lesions is a 30 to 45 day course of tetracycline (or another drug in this group) in combination with a 7 to 21 day course of aminoglycosides. (streptomycin or gentamicin). However, the optimal duration of treatment has not yet been determined.

In a prospective, randomized, double-blind, multicenter study by J. Solera et al. (Spain), the efficacy of treatment with doxycycline (100 mg orally twice a day) for 30 days and 45 days has been compared in patients with brucellosis not accompanied by endocarditis, spondylitis or lesions of the the nervous system. All patients also received gentamicin (240 mg IM once daily) for 7 days. The treatment outcome was assessed based on the incidence of relapse.

The study involved 146 patients, 73 in each group. Within 45 days of treatment completion, the rate of recurrence was significantly higher in the group of patients who received doxycycline for 30 days compared to those who received the drug for 45 days (12.3% vs 1.37%, relative risk 9.00; p = 0.017). In the following period (45 days to 12 months after the end of treatment), the recurrence rate in the two groups was almost equal (9.38% vs 11.11%, respectively; risk relative 0.84; p = 0.78).

In general, a relapse was observed in 15 (20.6%) patients who received treatment for 30 days and 9 (12.3%) who received the drug for 45 days (relative risk 1.67; p = 0.264). The compliance and incidence of adverse events were comparable in the two groups.

Thus, administration of doxycycline for 45 days has led to a significant reduction in the incidence of early relapse in adult patients suffering from brucellosis, without having a pronounced effect on the safety of treatment. This is particularly important in cases where access to medical care is limited, which increases the risk of early relapses, as well as the cost of their treatment.