Five Biovars of Yersinia enterocolitica Delineated by Numerical Taxonomy

Abstract

A total of 52 strains (41 of Yersinia enterocolitica strains, 3 Yersinia pseudotuberculosis strains isolated from animals, and 8 reference strains) were scored for 210 characters (64 morphological, 63 growth, 8 antibiotic susceptibility, and 75 biochemical) which were determined at both 37 and 22°C. The results were analyzed by numerical taxonomy methods (simple matching coefficients and clustering by unweighted average). The phenograms of the Y. enterocolitica strains delineated four and five phenons from the 37 and 22°C data, respectively. The phenons at 22°C were as follows: (i) rhamnose-negative, lecithinase- and sucrose-positive strains; (ii) rhamnose-, lecithinase-, and sucrose-negative strains; (iii) rhamnose- and lecithinase-negative, sucrose-positive strains ; (iv) rhamnose-, lecithinase-, and sucrose-positive strains; and (v) rhamnose-positive, lecithinasenegative, and sucrose-positive strains. These five phenons were designated biovars 1, 2, 3, 4, and 5, respectively. The phenograms of the Y. pseudotuberculosis strains delineated one phenon from both the 37°C data and the 22°C data. Three sucrose-negative strains of Y. enterocolitica had the same deoxyribonucleic acid base composition (guanine-plus-cytosine content) as a strain of serovar O3 of Y. enterocolitica and a strain of serovar IVA of Y. pseudotuberculosis.