title: Mycobacterium duvalii
text: # Mycobacterium duvalii
  
  Mycobacterium duvalii 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 pleomorphic acid-fast rods.
  
  Colony characteristics
  
  * Bright yellow pigmented, scotochromogenic and rough or smooth colonies on Löwenstein–Jensen medium.
  
  Physiology
  
  * Fast growth on Löwenstein–Jensen medium at 25 °C and 37 °C within 7 days. No growth at 45 °C.
  * Resistant to isoniazid, rifampicin, and sodium aminosalicylate.
  
  Differential characteristics
  
  * Characterised by the possession of 6 species-specific antigens demonstrable in immunodiffusion tests.
  
  Pathogenicity.
  
  ## Pathogenesis
  
  Not pathogenic, but evidence insufficient. Biosafety level 1.
  
  ## Type strain
  
  First isolated from cases of human leprosy by C. W. Duval. Strain ATCC 43910 = CCUG 41352 = CIP 104539 = DSM 44244 = JCM 6396 = NCTC 358.
  
  