[A comparative evaluation of the growth of Yersinia enterocolitica on elective media]

The aim of the work has been to find the optimal selective medium for the isolation of different serological and biochemical variants of Y. enterocolitica. Endo's, Ploskirev's, Lewin's, and bismuth sulfite media have been under study. Hottinger's agar, pH 7.2, has been used for the inoculation dose control. Forty Y. enterocolitica strain isolated from humans and animals have been employed in the study. Thirty-eight strains have been referred to 8 most prevalent serological variants and to 5 biochemical variants. The mean arithmetic values of the number of grown colonies with a 0.95 probability when inoculating 100 cells have been 74 +/- 1.6 in Hottinger's agar, 59 +/- 2 in Endo's medium, 62 +/- 2 in Ploskirev's medium, 50 +/- 1.3 in Lewin's medium, and 62 +/- 0.5 in bismuth sulfite medium. Endo's medium has been found the best. The colonies have been morphologically identical, without signs of dissociation. This medium has virtually yielded the same harvest as the rest media that yielded heterogeneous colonies. The biological characteristics of the strains grown in selective media have been unchanged.