Characterization of a Mycobacterium intracellulare variant strain by molecular techniques

This paper describes a Mycobacterium intracellulare variant strain causing an unusual infection. Several isolates obtained from an immunocompromised p atient were identified as members of the Mycobacterium avium complex (MAC) by the commercial AccuProbe system and biochemical standard identification. Further molecular approaches were undertaken for a more accurate character ization of the bacteria. Up to seven different genomic sequences were analy zed, ranging from conserved mycobacterial genes such as 16S ribosomal DNA t o MAC-specific genes such as mig (macrophage-induced gene). The results obt ained identify the isolates as a variant of M. intracellulare, an example o f the internal variability described for members of the MAC, particularly w ithin that species. The application of other molecular approaches is recomm ended for more accurate identification of bacteria described as MAC members .