Molecular profile of drug resistance in tuberculous meningitis from southwest china

Tuberculous meningitis (TBM) is the most severe form of extrapulmonary tuberculosis and causes high mortality and morbidity. Isoniazid resistance is strongly predictive of death in patients with TBM.

In the present study, using polymerase chain reaction (PCR) and Genotype MTBDRplus line-probe assay, we investigated the drug resistance in patients with TBM living in Southwest China.

Our results showed that only one-third of patients with TBM had a positive result for Mycobacterium tuberculosis culture from cerebrospinal fluid (CSF). PCR-based detection of M. tuberculosis DNA in CSF is not only an alternative diagnostic approach for TBM but also can be further used for the detection of drug resistance when combined with the MTBDRplus assay, the results of which were consistent with the classic drug susceptibility test. However, it further provided the molecular profile of the mutations can be conducted much faster than the classic drug susceptibility test can (1 day vs 30-40 days, respectively). In the studied 30 CSF samples from patients with TMB, we found a rate of 64.29% for isoniazid resistance, 39.29% for rifampicin resistance, and 32.14% for multidrug-resistant tuberculosis, which is relatively higher than the reported resistance in pulmonary tuberculosis. However, the molecular profile indicated that the most frequently observed mutations in the rpoB and katG genes are also responsible for drug resistance in TBM.

Our data suggest that the MTBDRplus line-probe assay is capable of detecting drug resistance for the CSF samples that have a PCR-positive result. We recommend PCR-based diagnosis and drug resistance test as routine assays for patients with suspected TBM.