The Journal of Medical Microbiology, Vol 33, Issue 4 223-226, Copyright © 1990 by Society for General Microbiology
Correlation between culture of Mycobacterium tuberculosis and detection of mycobacterial antigens in cerebrospinal fluid of patients with tuberculous meningitis
V. V. Radhakrishnan, S. Sehgal and A. Mathai
Department of Pathology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India.
A retrospective study was done to correlate culture of Mycobacterium
tuberculosis and detection of mycobacterial antigen in cerebrospinal fluid
(CSF) by an inhibition enzyme-linked immunosorbent assay (ELISA). M.
tuberculosis was cultured from CSF of 14 out of 70 patients with a clinical
diagnosis of tuberculous meningitis (TBM). Mycobacterial antigens were
demonstrated in CSF specimens by inhibition ELISA in all 14
culture-positive patients with antigen concentrations of 14.5-295 ng/ml
(mean 158.8 ng/ml). Thus there was positive correlation between the
detection of mycobacterial antigen and isolation of M. tuberculosis. Based
on this observation, 56 CSF specimens from culture-negative patients with
clinically diagnosed TBM were examined for mycobacterial antigen and the
data were compared with those from culture positive patients. ELISA gave
positive results in 38 specimens, with antigen levels of 12.5-280 ng/ml
(mean 152.6 ng/ml). In 70 CSF specimens from patients with non-tuberculous
neurological disease (control group), ELISA results were negative. Thus,
detection of mycobacterial antigen in CSF specimens by inhibition ELISA had
a specificity of 100% and a sensitivity of 67.8% for the diagnosis of TBM
and is of potential value in the laboratory diagnosis of TBM.
