RELATIONSHIPS AMONG STRAINS CLASSIFIED WITH THE RUMINANT PASTEURELLA HAEMOLYTICA-COMPLEX USING QUANTITATIVE-EVALUATION OF PHENOTYPIC DATA

The phenotypic relationships among 246 trehalose-negative strains clas sified under the [Pasteurella] haemolytica-complex in ruminants were i nvestigated by clustering and multidimensional ordinations based upon 79 phenotypic characters. A quantitative evaluation of phenotypic data using a S-level scoring system is presented permitting a comprehensiv e utilization of the recorded phenotypic variation among the strains i n the analyses. Clustering and ordination analyses display complementa ry aspects of data which has been clearly demonstrated in this investi gation. The main clusters revealed by the numerical techniques could b e related to distinctive phenotypic differences and showed an extensiv e correlation with the recognized biogroups. This classification was b ased only upon 4 characters (fermentation of L-arabinose, D-sorbitol, glucosides and ornithine decarboxylase). In contrast, there was no obv ious interpretation of the clusters formed by using binary scores. Phe notypic subgroups within the recognized biogroups have been described as well as a new, related group of bacteria, tentatively named Bisgaar d taxon 36. Quantitative interpretation of phenotypic data seems to re present a promising method for finding relations among affiliated stra ins of bacteria and to assist in forming hypotheses for subsequent gen otypic investigations.