Mycobacteria GroupN or rapid growers were classified into 12 clusters by the combined use of the five test characters, i.e., pigmentation on Lowenstein-Jensen medium containing soluble extracts (crocin) of Gardenia jasminoides(referred to L-J crocin medium), arylsulfatase, nitrate reductase, iron-uptake and 5,1´ NaCl tolerance, and the differential identification of Mycobacterium fortuitum and M. chelonei by the 5--test characters was evaluated with reference strains and isolates from sputa of patients with pulmonary tuberculosis -like diseases. In addition, the 5-day crocin reaction with different species or clusters of mycobacteria Group IV on L--J crocin medium was assessed.
Of 12 strains of M. fortuitum 9 strains(75.0%) belonged to cluster 5a, 2(16.7%) 5b and-one(8.3%)7a, respectively, and of two strains of M. chelonei one strain belonged to 8a and the other 8b. The 5-day crocin test also proved to be valuable in the rapid presumptive differentiation of M. fortuitum complex from other rapid growers.
|