Short, occasionally curved, gram-positive, nonmotile and strongly acid-fast rods. Colony characteristics *Nonpigmented and rough to smooth colonies. Physiology *Media have to be supplemented with 0.4% haemoglobin or 60 μM hemin (factor X) or 15 mg/ml ferric ammonium citrate respectively, but not with FeCl3 or catalase. *Slow growth on Löwenstein–Jensen medium or Middlebrook 7H10 agar at 32 °C within 2 to 4 weeks. *Growth slower at 25 °C and 35 °C and absent at 37 °C. *Strictly intracellular growth in tissue cultures of fibroblasts. Differential characteristics *Unique among mycobacteria in its requirement for hemin or ferric ammonium citrate for growth. Distribution.
Mycobacterium haemophilum
Mycobacterium africanum
Mycobacterium orygis
Mycobacterium canetti
Mycobacterium kansasii
Mycoplasma incognitus
Mycoplasma
Mycoplasma orale