Classification by Numerical Taxonomy of Staphylococci Isolated From the Bovine Udder

Abstract

Three hundred and three isolates obtained from plating bovine foremilk samples on Baird-Parker Agar were grouped using numerical taxonomy. Clustering of the isolates according to their percent similarity resulted in 19 groups; of these, eight groups contained over nine members. The other 11 groups contained 38 isolates. All 19 groups were joined at the 75% similarity level, with 17 of the groups being joined above the 85% similarity level. Results indicate that all but 16 of the isolates belonged to the same genus (Staphylococcus). and they probably belonged to one species (Staphylococcus aureus) or at least to closely related species. All but 17 isolates were catalase-positive. The greatest variations among the groups were in utilization of carbohydrates, chromogenesis, gelatinase production. and growth at 0 and 7 C and in 15% salt.