Recently developed laboratory diagnostic techniques have improved the isolation and identification of nontuberculous mycobacteria. Mycobacterium gordonae, a commonly found species of mycobacteria, is named after its discoverer, the American bacteriologist Ruth E. Gordon. It is classified in Runyon group 2 as a scotochromogenic organism.
Cultures are slow growing, smooth, and pigmented yellow.
M gordonae is referred to as the tap water bacillus because it is a frequent isolate in tap water. M gordonae is one of the least pathogenic of the mycobacteria. In the few published case reports of M gordonae disease, pathogenicity was not always established because of the presence of single isolates, the lack of confirmation by a reference lab, or the rapid improvement of pulmonary infiltrates, which are not characteristic features of other mycobacterial species. While there have been more than 100 case reports, most documentation supports contamination or colonization rather than pathogenicity. Additional studies with adequate documentation are warranted to investigate the pathogenicity of M gordonae .