Mycobacterium stomatepiae sp nov., a slowly growing, non-chromogenic species isolated from fish

Slowly growing, non-chromogenic mycobacteria were isolated from striped barombi mbo cichlids (Stomatepia mariae) maintained at the London Zoo Aquarium, UK. The isolates could be differentiated from other slowly growing, non-pigmented mycobacteria by a combination of phenotypic features including their inability to grow at 37 degrees C, positive tests for heat-stable catalase, tellurite reduction and arylsulfatase activity, and the absence of urease activity, Tween 80 hydrolysis, nitrate reductase, iron uptake and semiquantitative catalase. The almost full-length 16S rRNA gene sequence, together with partial sequences from the 65 kDa heat-shock protein (hsp65) and the beta-subunit of the bacterial RNA polymerase (rpoB) genes and the 16S-23S internal transcribed spacer 1 (ITS 1) region were identical for all three novel strains, but distinct from those of all known mycobacterial species. Phylogenetic analysis based on 16S rRNA gene sequences placed the novel isolates within the slowly growing mycobacteria group in close proximity to Mycobacterium florentinum. Based on genotypic and phenotypic findings, it is proposed that these isolates represent a novel species of the genus Mycobacterium, for which the name Mycobacterium stomatepiae sp. nov. is proposed with strain T11(T) (=DSM 45059(T) = CIP 109275(T) = NCIMB 14252(T)) as the type strain.