Evaluation of some diagnostic methods for the brucellosis in humans--a five year study

Brucellosis is a worldwide zoonosis with a high degree of morbidity in humans. In Bosnia and Herzegovina a progressive increase of brucellosis among humans is evident. As the clinical picture of human brucellosis is fairly non-specific, a definitive diagnosis requires isolation of the causative organism, or the demonstration of the high levels of specific antibodies, or seroconversion.

To analyse the diagnostic value of the Rose Bengal test, blood culture and immunoenzymatic test (ELISA IgM and IgG) in patients with brucellosis and to examine the relationship between these diagnostic methods.

We analysed the diagnostic methods in 525 brucellosis patients from 2004 to 2008. All patients were treated at the Infectious Diseases Clinic, University of Sarajevo Clinics Centre. The disease was diagnosed by positive blood culture results and/or by positive relevant serologic test results (ELISA, Rose-Bengal plate-agglutination test).

In total 162/525 (30.8%) patients had positive blood cultures. The Rose Bengal test was positive in all patients--525/525 (100.0%). Brucella IgM antibodies with ELISA were positive in 341/525 (64.8%). Early in infection, antibodies of the IgM class predominate. Brucella IgG antibodies with ELISA were positive in 236/525 (56%).

This study clearly showed that only a combination of blood culture, Rose Bengal test and ELISA ensured early and precise diagnosis of human brucellosis. The Rose Bengal test is excellent for screening. Blood culture gave excellent results in patients with primary infections. ELISA(IgM, IgG) is the method of choice for the diagnosis of chronic disease and relapse.