Mycobacterium tuberculosis is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid.Encyclopedia Entry for Mycobacterium Tuberculosis :Mycobacterium Tuberculosis. May cause:Autoimmune diseasesStrokeInformation from Marcello Allegretti.