Differential identification of mycobacteria. I. Tests on catalase activity.

The family Mycobacteriaceae is in great need of just such an unbiased method of classification, and the Adansonian approach has two advantages: if properly performed it should provide an unbiased grouping of organisms based upon their overall similarity in a variety of tests.

Abstract

In I957 Sneath (I) proposed the application of computer technology to the systematic classification of bacteria. Basically, this avoids the bias so common in present methods of bacterial nomenclature by assigning equal weight to all taxonomic features to be used in the classification scheme. Generally, a large group of organisms is subjected to examination for the presence or absence of a large number (60 to IOO) of features or characters. After subjecting each of the cultures to every test, the siinilarity between strains is determined mathematically as outlined by Sneath (1). Upon completion of such an impartial classification it might then be possible to weigh certain features more heavily as always, or almost always, being positive for a given group of organisms. This Adansonian approach has two advantages: (1) if properly performed it should provide an unbiased grouping of organisms based upon their overall similarity in a variety of tests; (2) once these groupings are realized a certain few features may stand out as being closely correlated with a given group, and hence of value to the diagnostic bacteriologist. The family Mycobacteriaceae is in great need of just such an unbiased method of classification. Since the isolation of the 11yellow bacillus (2) ushered in the modem era of atypical acid-fast bacilli in 1952, mycobacterial taxonomists have been enshrouded with the 11mycobacterial mystique (3). In his recent editorial, Wayne (3) reiter-