Mycobacterium cookii

Mycobacterium cookii

Description
Gram-positive, nonmotile and polymorphic acid-fast rods (0.8µm x 1.4µm – 1.9µm). Forms clumps, but not cords or cross bands. Does not form spores, capsules and aerial hyphae.

Colony characteristics
 * Colonies are smooth and glistening with yellow-orange pigmentation (0.5–1.0 mm diameter, scotochromogenic).

Physiology
 * Slow growth on Löwenstein-Jensen medium or Middlebrook 7H10 agar at 31°C (optimal temperature). No growth at 37°C, 42°C or 45°C.
 * Most of the strains are susceptible to ethambutol, isoniazid, streptomycin, and rifampin.

Differential characteristics
 * Phylogenetic position between the slowly growing pathogenic species and the saprophytic rapidly growing species by partial 16S rDNA sequencing.

Pathogenesis

 * Not pathogenic for humans, mice, guinea pigs and rabbits. Biosafety level 1.
 * Provokes a non-specific hypersensitivity reaction to bovine tuberculin.

Type Strain
Strain NZ2 = ATCC 49103 = CIP 105396 = DSM 43922 = JCM 12404.