Mycobacterium riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe assay.

A non-chromogenic, slowly growing Mycobacterium strain was isolated from a maxillary sinus lavage from a symptomatic patient in Riyadh, Saudi Arabia. It was initially identified as a member of the Mycobacterium tuberculosis complex by a commercial line-probe assay. Its 16S rRNA, hsp65 and rpoB gene and 16S-23S internal transcribed spacer sequences were unique; phylogenetic analysis based on the 16S rRNA gene sequence groups this organism close to Mycobacterium szulgai and Mycobacterium malmoense. Its unique biochemical properties and mycolic acid profile support separate species status. We propose the name Mycobacterium riyadhense sp. nov. to accommodate this strain. The type strain is NLA000201958(T) (=CIP 109808(T) =DSM 45176(T)).