Laboratory phenotypic features of the 12 most clinically important species of nonpigmented or late-pigmenting RGMa

Species or complexPrior designationsPigment3-Day aryl- sulfataseNitrate reductionIron uptakeUtilization of:5% NaClUnique PRA (hsp65)
M. chelonae-abscessus group
    M. abscessusM. chelonae subsp. abscessus+++
    M. chelonaeM. borstelense, M. chelonei, M. chelonae subsp. chelonae+++
    M. immunogenumM. immunogen++
M. fortuitum group
    M. fortuitumM. ranae, M. fortuitum biovar fortuitum+++++
    M. peregrinum (type 1)M. fortuitum biovar peregrinum (pipemidic acid susceptible)+++++c
    M. peregrinum (type 2)M. fortuitum biovar peregrinum (pipemidic acid resistant)+++++c
M. fortuitum third biovariant complex
    M. houstonense (proposed)M. fortuitum third biovar sorbitol positive+++++++c
    M. bonickei (proposed)M. fortuitum third biovar sorbitol negative++++++c
M. mucogenicumMCLO+±b+++
M. smegmatis group
    M. smegmatis sensu strictoM. smegmatis±++++±+++
    M. wolinskyiM. smegmatis++++±+++
    M. goodiiM. smegmatis±++++±+++
  • a Modified from reference 188. Symbols: ±, variable or late; +, ≥90%; −, ≤10%; ±, 11 to 89%.

  • b Tan appearance.

  • c M. peregrinum (type 1) has the same PRA pattern as the proposed M. bonickei (M. fortuitum third biovariant, sorbitol negative), whereas M. peregrinum (type 2) has the same PRA pattern as the proposed M. houstonense (M. fortuitum third biovariant, sorbitol positive). Biochemical testing is necessary for differentiation of these species and taxa.