Role of the BACTEC radiometric method in the evaluation of patients with clinically probable tuberculous meningitis

Background: Confirmation of tuberculous meningitis (TBM) and initiation of treatment are often delayed due to limitations in isolating Mycobacterium tuberculosis from cerebrospinal fluid (CSF). Objectives: To evaluate the role of the BACTEC radiometric method in a clinical setting for the early diagnosis of TBM. Materials and Methods: Patients meeting criteria for clinically probable TBM over a 3 year period were included. Clinical features, results of CSF investigations (protein, glucose, cell count, Ziehl-Neelsen staining, culture in Lowenstein-Jensen (LJ) medium and BACTEC) and brain CT imaging were reviewed. Drug sensitivity was tested using BACTEC. Patients were started on standard treatment and functional outcome, and response at discharge and follow-up were assessed. Patients were divided according to whether or not M. tuberculosis was isolated by BACTEC and the clinical, radiological, and laboratory features compared. Results: Sixty patients were evaluated. The mean age was 30 years 11.7 years. Headache and fever were the most common symptoms and the mean duration was 26 days. CT findings were hydrocephalus (n=21), basal exudates (n=16), and tuberculoma (n=14). In 40 patients, M. tuberculosis was isolated by BACTEC and average 15 days was required for detection, whereas it was 30 days in LJ medium. Results of drug-sensitivity testing (n=32) were obtained average 7 days after isolation. Patients from whom M. tuberculosis had been isolated by BACTEC more often had tuberculomas in CT imaging (P=0.018). Conclusion: Use of the BACTEC method allows early confirmation in patients with clinically probable TBM. It can guide clinicians in the rational use of anti-tuberculosis treatment by confirming diagnosis and identifying drug- sensitivity.