Over 7000 actinomycetes were fermented in 3 different media and extracted with 3 solvents. All were screened against M. tuberculosis for growth inhibition. Actives were profiled for potency and selectivity and 20 were scaled up for primary fractionation. Based on activity on primary fractions, 2 were scaled up for isolation of active principles. Ecumicin has demonstrated an excellent in vitro profile, activity vs. M. tb in mice at 20-32 mg/kg ip and subsequently shown to have some degree of oral bioavailability.