Identification of Mycobacterium fortuitum and Mycobacterium chelonei.

The study of 52 strains of rapidly growing mycobacteria showed that Mycobacterium fortuitum and M. chelonei were clearly distinguished by the aid of seven key tests (nitrate reductase, iron uptake, beta-glucosidase, penicillinase, growth on fructose, resistance to pipemidic acid, and resistance to capreomycin) and by analysis of their respective mycolic acids. However, the subdivision of these species into M. fortuitum var. fortuitum and M. fortuitum var. peregrinum and M. chelonei subsp. chelonei and M. chelonei subsp. abscessus was not satisfactorily accomplished.