PREVALENCE OF ORGANISMS DESCRIBED AS <i>ACTINOBACILLUS SUIS</i> OR HAEMOLYTIC <i>ACTINOBACILLUS EQUULI</i> IN THE ORAL CAVITY OF HORSES. COMPARATIVE INVESTIGATIONS OF STRAINS OBTAINED AND PORCINE STRAINS OF <i>A. SUIS SENSU STRICTO</i>

Abstract

Evidence was obtained to indicate that equine strains of organisms previously described as Actinobacillus suis or hemolytic variants of Actinobacillus equuli might constitute a separate group of organisms provisionally designated taxon 11. Four biovars were noticed within taxon 11. Selected DNA:DNA hybridizations support the classification of the mannitol positive biovar 2 of taxon 11 distinct from porcine A. suis. The final taxonomical position of taxon 11, however, has to await more detailed genetic studies including all biovars of taxon 11. A species name has not been suggested for the same reasons. The present observations also indicate that strains identified as taxon 11 apparently constitute a part of the normal bacterial flora in the oral cavity of horses.