Comparative diagnostic utility of metagenomic next‐generation sequencing, GeneXpert, modified Ziehl–Neelsen staining, and culture using cerebrospinal fluid for tuberculous meningitis: A multi‐center, retrospective study in China

BACKGROUND: Early diagnosis of tuberculosis meningitis (TBM) remains a great challenge during clinical practice. The diagnostic efficacies of cerebrospinal fluid (CSF)-based mycobacterial growth indicator tube (MGIT) culture, modified Ziehl-Neelsen (ZN) staining, Xpert MTB/RIF, and metagenomic next-generation sequencing (mNGS) for TBM remained elusive. METHODS: A total of 216 adult patients with suspicious TBM were retrospectively enrolled in this multi-cohort study. The diagnostic performances for MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS using CSF samples were evaluated. RESULTS: Uniform clinical case definition classified 88 (40.7%) out of 216 patients as the definite TBM, 5 (2.3%) patients as probable TBM cases, and 24 (11.1%) patients as possible TBM cases. The sensitivities of MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS for TBM diagnosis against consensus uniform case definition for definite TBM were 25.0%, 76.1%, 73.9%, and 84.1%, respectively. Negative predictive values (NPVs) were 66.0%, 85.9%, 84.8%, and 90.1%, respectively. The sensitivities of MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS for TBM diagnosis against consensus uniform case definition for definite, probable, and possible TBM were 18.8%, 57.3%, 55.5%, and 63.2%, respectively. Negative predictive values (NPVs) were 51.0%, 66.4%, 65.6%, and 69.7%, respectively. mNGS combined with modified ZN stain and Xpert could cover TBM cases against a composite microbiological reference standard, yielding 100% specificity and 100% NPV. CONCLUSION: Metagenomic next-generation sequencing detected TBM with higher sensitivity than Xpert, ZN staining and MGIT culture, but mNGS cannot be used as a rule-out test. mNGS combined with Xpert or modified ZN staining could enhance the sensitivity of diagnostic tests for TBM.