Numerical Classification of "Mycobacterium" rhodochrous and Runyon's Group IV Mycobacteria

Abstract

A numerical classification study was carried out on 129 strains representing “Mycobacterium” rhodochrous, Runyon’s Group IV mycobacteria, and other related taxa. Cultures of these strains were examined for 170 characters, and the resultant data have been analyzed by computer. Similarity coefficients were calculated in two ways: By the first, negative and positive matches were scored, and in the second, positive similarities only; in each case, clustering was with the average linkage cluster analysis technique. The two coefficients of association yielded the same four clusters, and, with a single exception, substantially the same subgroups. The three homogeneous clusters corresponded to: (i) “M.” rhodochrous, (ii) Nocardia pellegrino, and (iii) Mycobacterium Group IV. Twenty-three named mycobacteria were recovered in seven subgroups, six of which were equated with the established taxa M. borstelense, M. chitae. M. gallinarum M. fortuitum, M. smegmatis, and M. vaccae. Characters were abstracted from the data and used for the identification of clusters and subgroups.