Identification of an emerging pathogen, Mycobacterium massiliense, by rpoB sequencing of clinical isolates collected in the United States

Abstract

Mycobacterium massiliense is a rapidly growing mycobacterium that is indistinguishable from Mycobacterium chelonae/M. abscessus by partial 16S rRNA gene sequencing. We sequenced rpoB, sodA, and hsp65 genes from isolates previously identified as being M. chelonae/M. abscessus and identified M. massiliense from isolates from two patients with invasive disease representing the first reported cases in the United States.

FIG. 1.

Phylogenetic trees of rpoB (A) and sodA (B) gene sequences. Bootstrapping values over 70% are recorded at the tree nodes. Mycobacterium leprae was used as an outgroup. Study isolates are designated AP001 to AP063. Isolates identified as being M. massiliense by rpoB sequencing are in boldface type. Isolates AP002 and AP008 represent patient 1, and isolates AP025 and AP038 represent patient 2. ^aIncludes isolates AP001, AP004 to AP007, AP009 to AP011, AP013 to AP015, AP017, AP020, AP021, AP023, AP024, AP026 to AP030, AP032 to AP036, AP039, AP041 to AP052, and AP056 to AP063. ^bIncludes isolates AP004 to AP007, AP009 to AP011, AP013 to AP015, AP017, AP020, AP021, AP023, AP024, AP026 to AP028, AP030, AP032 to AP036, AP039, AP041, AP042, AP044 to AP052, AP056, AP059, and AP061 to AP063. ^cIncludes isolates AP001, AP002, AP003, AP008, AP025, AP029, AP038, AP043, AP057, AP058, and AP060. ^dPublished sodA sequences for M. massiliense (GenBank accession number AY593975) and M. abscessus (accession number AY458102) differed by only 2 bp.