Although brucellosis has higher prevalence in certain geographic areas, it is well recognized throughout the world. Human brucellosis is traditionally described as a disease of protean manifestations and there is no diagnostic laboratory test. In this case report, we to report a 14-years-old girl whose main symptom was back pain and whose Brucella agglutination tests were negative in the early period, turning to positive later, and in whom Brucella genus bacteria was isolated from bone marrow aspiration culture. With this case we point out the importance of repeating diagnostic tests in highly suspected cases. In case of radiologically proven sacroileitis, Brucella infection should be kept in mind in differential diagnosis.

Keywords: Brusella, adölesan, sakroilleit, brucellosis, adolescent, sacroileitis