M. tuberculosis molecular variation in CNS infection : Evidence for strain-dependent neurovirulence

To determine the molecular diversity among Mycobacterium tuberculosis isolates associated with central nervous system tuberculosis (CNS TB) in a defined cohort of HIV uninfected patients. A retrospective analysis was performed of clinical and laboratory data for all patients with CNS TB diagnosed in Manitoba, Canada, between 1979 and 1996. Restriction fragment-length polymorphisms (RFLP) of archival isolates of M. tuberculosis from CNS TB patients were determined and interpreted against the frequency of different isolates from all TB patients in the years 1992 to 1996. Among 2,334 patients with active TB, CNS TB was diagnosed in 42 (1.8%); meningitis with or without tuberculoma in 76%; and tuberculoma alone in 24%. CNS TB patients were significantly more likely to be young (