Identification of Mycobacterium neoaurum isolated from a neutropenic patient with catheter-related bacteremia by 16S rRNA sequencing

A rapidly growing pigmented mycobacterial strain with an ambiguous biochemi cal profile was isolated from the blood culture taken through the Hickman c atheter of a 9-year-old girl with acute lymphoblastic leukemia. Whole-cell fatty acid analysis showed that the best match profile was that of Mycobact erium aurum, but the similarity index was only 0.217, meaning that there we re no good matches between the isolate and the organisms in the database of the Microbial Identification System. The 16S rRNA gene of the mycobacteria l strain was amplified, agarose gel purified, acid sequenced. There were 44 base differences between the gene sequence of the isolate and that of M. a urum but only one base difference between the sequence of the isolate and t hat of Mycobacterium neoaurum, showing that the isolate was indeed a strain of M. neoaurum by using this "gold standard." This represents the first ca se of M. neoaurum infection documented by 16S rRNA sequencing.