title: Mycobacterium cookii
text: # Mycobacterium cookii
  
  Mycobacterium cookii is a species of the phylum Actinomycetota (Gram-positive bacteria with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus Mycobacterium.
  
  ## Description
  
  Gram-positive, nonmotile and polymorphic acid-fast rods (0.8 µm x 1.4–1.9 µm). 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 saprotrophic 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.
  
  