Infection due to Mycobacterium haemophilum identified by whole cell lipid analysis and nucleic acid sequencing

A patient with indolent, non-Hodgkin's lymphoma developed a pretibial soft tissue abscess caused by a fastidious mycobacterium. Because the organism could not be definitively identified by standard microbiologic testing, whole cell fatty acid analysis and 16S rDNA sequencing were performed. These procedures identified the organism as Mycobacterium haemophilum. We review the diagnostic considerations with regard to this pathogen.