Evaluation of CSF pyrosequencing to diagnose tuberculous meningitis: A retrospective diagnostic accuracy study

Background We evaluated the performance of pyrosequencing, a genotypic test which detects TB and XDR-defining mutations within 6 h, directly on CSF samples for diagnosing TB meningitis(TBM). Methods This retrospective, diagnostic accuracy study was conducted in Hinduja hospital, Mumbai from May-2017 to May-2019. 107 consecutive patients with physician-suspected TBM for whom CSF pyrosequencing was requested were screened. Seven patients with incomplete data were excluded. Diagnostic accuracy of pyrosequencing was compared with Xpert MTB/Rif and TBMGIT (TB Mycobacterial Growth Indicator Tube) culture against the uniform case definition of definite or probable TBM. Susceptibility concordance rate of pyrosequencing with TBMGIT culture and Xpert MTB/Rif was determined. Results The study cohort comprised of 100 patients[Definite(n = 33), Probable(n = 20), Possible(n = 30), Alternative(n = 17)] with 50% males[median age(years):38(Range:2-87)]. Against the uniform case definition, pyrosequencing had 98·11%(95%CI 89·93-99·95; n = 52/53) sensitivity and 97·79%(86·31-99·67; n = 44/45) negative predictive value(NPV) compared with 43.39%(29·83-57·72; n = 23/53,p Conclusion CSF pyrosequencing is significantly more sensitive than Xpert MTB/Rif and TBMGIT culture for diagnosing TBM. Additionally, it facilitates early therapeutic decision-making by providing information on XDR-defining mutations.