TAXONOMY OF ENTEROCOCCI BY COMPUTER ANALYSIS

Abstract

A total of 48 pure cultures of Streptococcus (including 12 ATCC strains) belonging to the fecal, pyogenic, and viridans groups was studied in an effort to derive a numerical taxonomy of the enterococci based on Adansonian principles. Each of these cultures was subjected to a variety of tests. The data so obtained was encoded and analyzed by electronic computers, ft showed two major taxonomic groups: a large homogeneous cluster of all enterococcal strains tested and a discrete cluster of streptococci belonging to the pyogenic and viridans groups, showing the least cross relationships with all of the enterococcal strains including S. bovis. The large enterococcus group comprised S. faecalis, unclassified enterococci, S. bovis, S. durans, and S. faecium within the major group. The S. faecalis cluster of strains showed three discernible subgroupings of S. faecalis (typical), var. liquefaciens, and var. zymogenes. The "unclassified" types formed a rather homogeneous cluster which may warrant formal recognition as a separate species. S. bovis was most closely related to the unclassified species group. The results of analysis support the proposed determinative classification of enterococci (16).