An Unclassified "Unclassified" Mycobacterium

Abstract

An unusual unclassified mycobacterium has been repeatedly recovered over a period of years from a 46-year-old white woman with persistent respiratory symptoms and a slowly progressive pulmonary disease. Although the mycobacterium in this case was probably an opportunistic secondary invader, it appears to have played a role in the more recent progression of symptoms and roentgenographic pulmonary changes. The organism has been thoroughly studied but fails to conform fully to any of the usual subgroups of the unclassified mycobacteria as characterized in the currently employed schema. This case report emphasizes the increasing clinical and bacteriologic importance of the unclassified mycobacteria and presents a systematic approach to their identification through careful cultural, morphologic, and biochemical characterization.