“Mycobacterium tilburgii, ” a Newly Described, Uncultivated Opportunistic Pathogen

Molecular methods are increasingly used to identify pathogens that are difficult to cultivate. We report a case of disseminated infection with “Mycobacterium tilburgii, ” a proposed species that has never been cultivated. The case illustrates the diagnostic utility of sequence analysis of the 16S rRNA gene directly from clinical specimens. Molecular methods are increasingly used to detect patho-gens that are difficult to cultivate or have thus far not been cultivated. Amplification and sequencing of the 16S rRNA gene directly from clinical specimens can produce data that enable rapid detection of such organisms and their identifica-tion to the species level (2, 5). “Mycobacterium tilburgii ” is a proposed species that has not been cultivable and has been reported in only four previous patients. It was first described by Buiting et al. in a previously healthy woman with acid-fast smear-positive infection of her bowels and bladder (1, 9). The organism had a unique 16S rRNA gene sequence and wa