Interspecies and intraspecies variation observed a 10 species ofMycobacterium. Values represented are percent variation based on 705 bp of the rpoB gene for M. tuberculosis (Mt),M. avium (Ma), M. intracellulare (Mi), M. gordonae (Mg), M. chelonae (Mc), M. xenopi (Mx),M. scrofulaceum (Msc), M. smegmatis (Ms), M. kansasii (Mk), M. fortuitum (Mf). Data from M. scrofulaceum are represented by two isolates.