A rare case of seronegative neurobrucellosis.

Neurobrucellosis is one of the complications of brucellosis. We report a rare case of a 17-year-old girl with seronegative neurobrucellosis and depression and diplopia. Results of agglutination tests for Brucella both in serum and CSF were negative. Diagnosis was made only by positive culture of Brucella mellitensis with inoculation of the patient's cerebrospinal fluid in a BACTEC 9050 System. The patient was successfully treated using ceftriaxone, doxycycline and rifampicin therapy for six months.