Phylum Actinobacteria, Class Actinobacteria, Order Actinomycetales, Suborder Corynebacterineae, Family Mycobacteriaceae, Genus
Mycobacterium, Mycobacterium saskatchewanense Turenne et al. 2004.
Member of the Mycobacterium simiae complex.
Acid-alcohol-fast, long, beaded rods.
Colonies on Middlebrook 7H10 agar develop after incubation for 2-4 weeks; they are
initially transparent, but mature colonies show a bright yellow scotochromogenic
pigmentation in a raised center, and a transparent irregular apron. Growth on
Lowenstein-Jensen medium is rough and dry in texture. Temperature range for
growth is 25-37 ºC; optimal temperature for growth is 37 ºC;
does not grow at 42 ºC. No growth on media supplemented with 5% (w/v) NaCl.
Some strains grow on MacConkey agar without crystal violet.
Isolated from sputum and human respiratory samples.
Susceptible to rifampin (32 µg/ml) and streptomycin (8 µg/ml). Resistant to ethambutol (2 µg/ml) (variable), isoniazid (1 µg/ml).
- John G. Magee and Alan C. Ward 2012. Family III. Mycobacteriaceae Chester 1897, 63AL in Bergey’s Manual of Systematic
Bacteriology, Volume Five The Actinobacteria, Part A, Michael Goodfellow & al. (editors), 312-375.
- Turenne CY, Thibert L, Williams K, Burdz TV, Cook VJ, Wolfe JN, Cockcroft DW, Kabani A. Mycobacterium saskatchewanense sp.
nov., a novel slowly growing scotochromogenic species from human clinical isolates related to Mycobacterium interjectum and
Accuprobe-positive for Mycobacterium avium complex. Int J Syst Evol Microbiol 2004; 54:659-667.
Positive results for thermotolerant catalase (68 ºC), and Tween 80 hydrolysis.
Negative results for acid phosphatase, arylsulfatase (3 and 14 days), niacin accumulation, nitrate reduction, pyrazinamidase, and
Variable results for catalase (semi-quantitative) and tellurite reduction.
(c) Costin Stoica