Laboratory parameters and serum tube agglutination test as markers for brucellosis treatment response

This study aims to compare the clinical, laboratory, and therapeutic outcomes between acute and subacute/chronic phases of brucellosis and to identify independent predictors of a favorable treatment response. This retrospective observational and analytic study included 171 patients with brucellosis, categorized as acute (n = 146) or subacute/chronic (n = 25). A therapeutic response was defined as the complete resolution of initial symptoms with no relapse during a 12-month follow-up. A serological response was defined as a ≥4-fold decrease in the serum tube agglutination (STA) titer post-treatment. Outcomes were compared using appropriate statistical tests (p < 0.05), and logistic regression was used to identify predictors of response. Compared to the subacute/chronic group, patients with acute brucellosis had a significantly higher frequency of leukopenia (21.2 % vs. 0 %; p < 0.01), elevated C reactive protein (CRP) (76.7 % vs. 52.0 %; p = 0.01), and elevated transaminases (43.8 % vs. 20.0 %; p = 0.025). A significantly higher therapeutic response rate was observed in acute cases (93.2 %) compared to subacute/chronic cases (0.76 %) (p = 0.01). Multivariate analysis identified elevated baseline CRP (OR: 4.00; p = 0.02) and a post-treatment decrease in STA titer (OR: 5.84; p = 0.007) as independent predictors of a favorable therapeutic response. In conclusion, acute brucellosis presents with a more pronounced inflammatory profile than subacute/chronic forms. While patients with acute brucellosis demonstrated a significantly higher therapeutic response rate, the serological response was also more pronounced in this group. Elevated CRP at diagnosis and a significant decrease in STA titer post-treatment are strong, independent predictors of successful outcomes, highlighting their value in patient monitoring.