The weight, clinical examination and survival of mice were followed weekly for 90 days. All mice (all survivors) were killed by exsanguination at day 90 post-infection. The lungs, spleen and liver were removed. One portion of each organ was homogenized in Middlebrook 7H9 broth to determine the mycobacterial load after
serial dilutions and plating on Middlebrook 7H10 at 37 uC under a
5% CO2 atmosphere for 10 days. The remaining portion of each
organ was fixed with 10% formalin for histopathological analyses