Under a magnification of 3841X, this scanning electron micrograph (SEM) revealed some of the ultrastructural morphologic details exhibited by a number of Gram-positive bacilli, or ?rod-shaped?, Mycobacterium fortuitum bacteria. M. fortuitum is classified as a ?rapidly-growing? Mycobacterium, due to the fact that it can be grown on laboratory culture medium in less than 7 days. As a human pathogen, this organism has been determined to be the cause of skin infections, including furunculosis, i.e