Molecular Methods and Culture in Diagnosis of Tuberculous Meningitis in Children

Objectives: This study aimed to detect the incidence of tuberculous meningitis (TM) in pediatric patients using GenoType MTBDRplus, GenoType MTBDRsl, and Mycobacteria Growth Indicator Tube (MGIT). Additionally, it aimed to evaluate the utility of GeneXpert MTB/RIF assay in the detection of Mycobacterium tuberculosis in comparison to MGIT culture. Methods: Children under or equal to 15 years of age who were clinically suspected of tuberculous meningitis (TBM) were included in the study. Cerebrospinal Fluid (CSF) samples were collected and tested for GeneXpert MTB/RIF assay and MGIT culture. Culture-positive samples were further analyzed using Line Probe Assay (LPA) to detect drug-resistant mycobacteria. Results: Out of 272 CSF samples, 28 (10.3%) samples were positive for MTB, and 5 (17.8%) were MDR- TB. GeneXpert MTB/RIF assay detected 23 (8.4%) MTB cases of which 3 (13%) were rifampicin- resistant. MGIT culture detected the presence of MTB organism in 19 (6.9%) cases, of which 6 (31.6%) were isoniazid-resistant and 2 (10.5%) were rifampicin-resistant by first line LPA. None of the samples had Extensively Drug-Resistant TB (XDR-TB). GeneXpert MTB/RIF assay had 73.6% sensitivity and 96.4% specificity taking MGIT as a gold standard. Conclusion: Total positivity for MTB was seen in 10.3% cases, among which 17.8% were MDR-TB; no XDR-TB was detected in pediatric patients. GeneXpert MTB/RIF assay is a rapid and reliable method for diagnosis of tuberculous meningitis but may miss some cases, so samples should also be cultured in MGIT to enhance yield and for extended sensitivity panel. J Microbiol Infect Dis 2021; 11(3):140-146.