Murine model of TB meningitis

AbstractBackgroundCentral nervous system (CNS) infections caused by Mycobacterium tuberculosis (MTB) are the most severe forms of extrapulmonary TB (EPTB) due to high levels of mortality and neurological morbidity. Limited studies are available on CNS-TB animal-model development, despite the steady rise in cerebral-TB cases in India over the past decade. This study describes the development of a murine model of CNS-TB using a clinical strain (C3) isolated from the cerebrospinal fluid (CSF) of CNS-TB patients.MethodsGroups of mice were infected intravenously with an MTB C3 strain isolated from the CSF of CNS-TB patients in order to mimic the dynamics of actual infection. Brain and lung tissue were evaluated for bacterial burden, as well as histopathology and surrogate markers of TB infection at 30- and 50-days post-infection.ResultsMice infected intravenously with MTB C3 strains showed progressive development of CNS disease, with high bacillary burden in the lungs during the initial stage (30days), which eventually disseminated to the brain at a later stage (50days). All C3-infected mice showed elevated levels of mycobacterial antigens and antibodies, as well as increased T cell adenosine deaminase activity in brain homogenates, which explicitly correlated with mycobacterial load in the brain and chronic brain pathology. High mortality rates (60%) were associated with mice infected with the C3 strain as compared to those of controls.ConclusionOur findings demonstrated the design of a novel murine model of CNS-TB using a C3 strain and that replicated events of EPTB dissemination. This model will promote efforts to understand the pathogenesis CNS-TB infection for development of improved therapeutic interventions in the future