DNA relatedness among established Ureaplasma species and unidentified feline and canine serogroups

The levels of DNA relatedness among two unclassified feline ureaplasma serogroups, four unclassified canine ureaplasma serogroups, and the three previously established Ureaplasma species were examined and compared. The strains examined included five feline strains representing two feline serogroups, four canine strains representing four canine serogroups, and the type strains of the three established species. Each strain representing each species or serogroup exhibited 78% or more actual DNA homology with its homologous DNA, but less than 10% DNA homology with DNAs from the heterologous strains. These findings indicate that each of these human, bovine, avian, feline, and canine strains is genomically distinct. In addition, the three previously recognized species (Ureaplasma urealyticum [human], Ureaplasma diversum [bovine], and Ureaplasma gallorale [avian]), which were established on the basis of phenotypic properties, were also shown to be genomically distinct. The three feline serogroup SI strains were genomically related (from 89 to 100% DNA homology) to each other but were unrelated (less than 10% DNA homology) to the feline serogroup SII strains, indicating that these two feline serogroups are also genomically distinct. Conversely, the two feline serogroup SII strains were genomically very similar (from 83 to 100% DNA homology) to each other but were unrelated (less than 10% DNA homology) to the three feline serogroup SI strains. However, canine serogroup SI strain D1M-C exhibited 73% DNA homology with serologically distinct canine serogroup SII strain D29M, indicating that these strains representing two separate serogroups belong to the same genomic species.(ABSTRACT TRUNCATED AT 250 WORDS)