Characterization of Mycobacterium montefiorense sp. nov., a novel pathogenic Mycobacterium from moray eels that is related to Mycobacterium triplex

Abstract

The characterization of a novel Mycobacterium sp. isolated from granulomatous skin lesions of moray eels is reported. Analysis of the hsp65 gene, small-subunit rRNA gene, rRNA spacer region, and phenotypic characteristics demonstrate that this organism is distinct from its closest genetic match, Mycobacterium triplex, and it has been named M. montefiorense sp. nov.

FIG. 1.

Mycolic acid profiles of M. triplex ATCC 700071 (A) and M. montefiorense BAA-256 (B). LU, luminosity units; IS, internal standard. Note that luminosity units are just a measure of the fluorescence detector's signal intensity, a relative scale.

FIG. 2.

Phylogenetic tree of Mycobacterium sp. type strains based on full 16S rRNA gene sequences including a bootstrap (with a heuristic search) 50% majority rule consensus tree (100 bootstrap replicates were run). Bootstrap analysis was performed with a 50% majority rule consensus tree by using PAUP 4.0 (D. Swofford, Sinauer Associates, Inc.) One hundred bootstrap replicates were run. The optimality criterion was maximum parsimony, and there were 95 parsimony-informative characters among the 1,533 characters (nucleotide positions) analyzed. M. marinum is known to cluster between M. tuberculosis and M. conspicuum. A neighbor-joining tree constructed by using the MicroSeq Microbial Identification and analysis software and database (Applied Biosystems) yielded similar results (data not shown; 12). On the phylogenetic tree, each organism is indicated by the genus, species, GenBank accession number, ATCC or DSM strain number, and MicroSeq accession number (if available).

FIG. 3.

Alignment (Lasergene MegAlign; DNASTAR, Inc.) of rRNA 16S-23S ITS regions of M. triplex, M. montefiorense, M. simiae, M. genavense, and an M. triplex-like organism (4).