This contract evaluates the efficacy of compounds against M. tuberculosis in animal models. Services provided include: quantitative assessments of efficacy and toxicity;determination of optimal dosages, routes and schedules of administration;development and use a mouse model of latent infection;evaluation of advanced compounds in guinea pigs;determination of achievable plasma and tissue levels, including estimation of maximum plasma concentrations, approximate plasma half-life, and bioavailability;determination of drug efficacy against M. tuberculosis growing intracellularly in cultured mammalian cells;characterization and improvement of animal models of immunocompromised hosts;and preparation of samples of purified organisms or animal tissues and fluids for analysis of drug or metabolite concentrations.