Numerical Classification of the Tribe Klebsielleae

Abstract

SUMMARY: A numerical classification study was carried out on 177 strains of Klebsiella and related groups. Three methods of numerical classification were used: median sorting, single linkage cluster analysis and minimum spanning tree. All three contributed to the final decision on the taxa, but yielded substantially the same results. Of the three, the median sorting, if used alone, would have provided the most information. The validity of the genus Klebsiella was confirmed but the inclusion of the three recognized species of Enterobacter in one genus was not confirmed. The genus Klebsiella was divided into six taxa, one of which is proposed as K. mobilis synon. Enterobacter aerogenes. E. cloacae occupied a rank similar to that of the genus Klebsiella, while E. liquefaciens was most closely related to the genus Serratia and it is proposed to include it as S. liquefaciens. Enterobacter ‘pigmentés’ was found to be closely related to Chromobacterium typhiflavum.