Plasmid profiles ofMycobacterium fortuitum complex isolates

Six plasmids differing in molecular weights were found in isolates ofMycobacterium fortuitum, M. chelonae, and other nonclassified, nonchromogenic, rapidly growing mycobacteria. One of the plasmids of molecular weight of 32.0 Kb was present in all strains analyzed; a large plasmid of 112.0-Kb molecular weight was present only in strains identified asM. fortuitum var.peregrinum. Although the strains had distinct plasmid profiles, none of the 15 cultural and biochemical properties and susceptibility to 18 drugs that were tested could be attributed to the occurrence of these plasmids.