MYCOBACTERIUM BRANDERI SP-NOV, A NEW POTENTIAL HUMAN PATHOGEN

A number of mycobacterial strains with similar growth characteristics, metabolic properties, and lipid compositions, which were previously p laced in the Helsinki group (E. Brander, E. Jantzen, R. Huttunen, A. J untunen, and M.-L. Katila, J, Clin, Microbiol, 30:1972-1975, 1992), we re characterized by performing 16S rRNA gene sequencing. Of the 14 str ains studied, 9 had a unique, previously undescribed sequence in the v ariable region of 16S rRNA. These nine strains, all of which were isol ated from respiratory tract specimens, were nonpigmented and grew at 2 5 C to 45 degrees C, reaching full colony size after 2 to 3 weeks. The y produced arylsulfatase, nicotinamidase, and pyrazinamidase and were negative for Tween 80 hydrolysis, catalase, urease, and nitrate reduct ase activities, and niacin. Their glycolipid patterns were identical. A mycolic acid analysis performed by using thin-layer chromatography s howed that these organisms contained alpha-mycolates, ketomycolates, a nd carboxy mycolates. Gas-liquid chromatography revealed that 2-eicosa nol was the major alcohol and hexacosanoic acid was the major mycolic acid cleavage product. On the basis of their growth, biochemical, and lipid characteristics and their unique 168 rRNA sequence, we propose t hat these organisms should be assigned to a new species, Mycobacterium branderi. Comparative 168 rRNA sequencing revealed that this new spec ies is closely related to Mycobacterium celatum, Mycobacterium cookii, and Mycobacterium xenopi. Strains 52157(T) (T = type strain) and 4354 8 have been deposited in the American Type Culture Collection as strai ns ATCC 51789 and ATCC 51788, respectively.