Demonstration of heterogeneous genotypes of Taylorella equigenitalis isolated from horses in six european countries by pulsed-field gel electrophoresis

Forty-six isolates of Taylorella equigenitalis were analysed by pulsed-fiel d gel electrophoresis (PFGE) after separate digestion of the genomic DNA wi th ApaI and with NotI. The isolates had been obtained from horses in six Eu ropean countries and were classified into 18 genotypes. In Belgium, 2 genot ypes were detected in 2 isolates, in England 9 among 15, in Finland 2 in 2, in France 2 among 10, in Sweden 3 among 5, and in Switzerland 3 among 12. Two English isolates and 4 French isolates gave identical PFGE profiles to those of Kentucky 188 from the United States. A common genotype was found i n 5 isolates from Belgium and England and also in 10 isolates from France a nd Switzerland. The analysis of genomic DNA from 12 isolates of T. equigeni talis obtained from male horses in France, Sweden and Switzerland gave no e vidence of a sex-related difference in the genomic DNA. Genomic DNA from 11 streptomycin (STM)-susceptible isolates obtained in Sweden and Switzerland were classified into four genotypes by PFGE. Each of the six genotypes det ermined among the 17 isolates from these two countries had single phenotype s for resistance or susceptibility to STM.