16S rRNA gene multiplex PCR comparing M. intracellulare and M. chimaera (9). The two species are indistinguishable by this method. Lane 1, 100-bp ladder; lane 2, M. chimaera type strain DSM 44623T; lane 3, M. chimaera isolate from household water sample; lane 4, M. intracellulare type strain ATCC 13950T; lane 5, M. intracellulare patient isolate; lane 6, M. marseillense isolate from household water sample. Molecular weight markers are shown to the left.