Mycobacterium branderi sp. nov., a new potential human pathogen

Area of Science:

• Microbiology
• Molecular Biology
• Taxonomy

Background:

• Previously, several mycobacterial strains with similar characteristics were grouped under the Helsinki group.
• These strains displayed consistent growth, metabolic, and lipid profiles.

Purpose of the Study:

• To characterize previously grouped mycobacterial strains using 16S rRNA gene sequencing.
• To determine the taxonomic classification of nine unique strains isolated from respiratory specimens.

Main Methods:

• 16S rRNA gene sequencing was performed on 14 mycobacterial strains.
• Biochemical tests (arylsulfatase, nicotinamidase, pyrazinamidase, Tween 80 hydrolysis, catalase, urease, nitrate reductase) were conducted.
• Lipid analysis included glycolipid patterns, mycolic acid analysis (thin-layer chromatography), and fatty acid analysis (gas-liquid chromatography).

Main Results:

• Nine of the 14 strains possessed unique 16S rRNA sequences.
• These nine strains shared identical glycolipid patterns and specific biochemical characteristics.
• Mycolic acid analysis revealed alpha-mycolates, ketomycolates, and carboxy mycolates; 2-eicosanol and hexacosanoic acid were major products.

Conclusions:

• The distinct genetic, biochemical, and lipid profiles support the classification of these nine strains as a new species, Mycobacterium branderi.
• Mycobacterium branderi is phylogenetically related to Mycobacterium celatum, Mycobacterium cookii, and Mycobacterium xenopi.
• Type strains have been deposited in the American Type Culture Collection for future reference.