Serological comparison of bovine Ureaplasmas.

Forty-five bovine Ureaplasma strains were examined serologically by thegrowth inhibition and metabolism inhibition tests. They were found to be of considerableheterogeneity, and divided into three distinguishable serological groups. These groups, I, II and III, were composed of 24, 20 and one strains, respectively. Although no antigenicalcross-reaction was shown among the three groups by the growth inhibition test, a con-siderable amount of cross-reaction was recognized between groups I and II by the meta-bolism inhibition test. The strain of group III was distinct from any strain of the othergroups. Based on the results obtained, 7 strains were selected as the representatives of allthe strains studied. Twenty-six new isolates were further examined with antisera againstthe representative strains, and serotyped readily. Therefore, it seemed reasonable for the7 strains to have been selected as the representative serotypes of the bovine ureaplasmas.No serological relationship was shown between any bovine strain and any one of the 8human serotypes of Ureaplasma urealyticum.