Mycobacterium fortuitum


  • Rapidly-growing, nonchromogenic, non-tubercular mycobacterium (NTM).
    • May stain Gram positive [Fig] and resemble Nocardia spp.
    • Upon AFB staining, rod form are usually 1-3 µm x 0.2-0.4 µm, and occasionally beaded, causing confusion with Nocardia.
  • Typically takes 3-7 days for clinical cultures to become positive, but may require longer incubation.
    • Löwenstein-Jensen media has been classically used to culture the organism.
  • Reservoirs: soil, water, animals, marine life--worldwide distribution.
    • Can be found as part of a biofilm environment.
  • M. fortuitum group includes M. peregrinum, M. houstonese, M. boenickei, M. mageritense, M. senegalense and Mycobacterium setense sp. nov. Differentiation only by molecular testing.

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Last updated: May 1, 2023