The application of numerical taxonomy in the classification of staphylococci from bovine milk

Abstract

One-hundred-and-two isolates of staphylococci from bovine milk were each subjected to a battery of 19 different tests. With the application of numerical taxonomy these isolates could be classified into 1 genus and 3 different species. Although the majority of the coagulase negative organisms were grouped as 1 species, the biochemical differences within this group indicated that they should belong to at least 2 species. About 50% of these isolates could be designated Staphylococcus epidermidis. Possibly because of the small number of tests, a finer division into different species could not be made. The coagulase-positive organisms could be divided into 2 species, the smaller group of which consisted of 3 isolates only. If used as the only method for identification, the coagulase test produces false positive results at a rate of about 2,5% of cases and false negative results at a rate of about 1,7%.