16S rRNA sequence analysis of an isolate of Mycobacterium haemophilum from a heart transplant patient

Biopsy samples from a heart transplant patient with cellulitis and bursitis yielded an isolate of Mycobacterium haemophilum. The isolate was identified on the basis of a growth requirement for haemin or ferric ammonium citrate, growth at 30 degrees C but not at 37 degrees C, negative catalase test, intracellular growth in McCoy fibroblasts and sequence identify with a portion of the 16S rRNA sequence of the type strain. In comparisons with known 16S rRNA sequences, M. haemophilum grouped with other pathogenic, slow-growing mycobacteria, showing close sequence similarity to M. marinum (98.8%) and lower similarity to M. ulcerans and M. tuberculosis complex organisms. M. haemophilum and M. marium share other features including optimal growth at 30 degrees C and the ability to cause superficial skin lesions in man.