Genetic and phenotypic comparison of three new avian Haemophilus-like taxa and of Haemophilus paragallinarum Biberstein and White 1969 with other members of the family Pasteurellaceae Pohl 1981.

In the course of post-mortem bacteriological examinations, several previously unreported bacterial strains were isolated from budgerigars, pigeons, kestrels, and a goose. They have been separated into three distinct collectives according to their cultural, morphological, and biochemical characteristics. Since they require V factors, they were tentatively assigned to the genus Haemophilus Winslow et al. 1917. This preliminary classification was checked by determination of guanine + cytosine contents and genome sizes and by DNA:DNA hybridization tests among reference strains of the three new avian taxa and recognized species of the family Pasteurellaceae Pohl 1981. With the same methods, the genetic relationships of Haemophilus paragallinarum Biberstein and White 1969 within the family were determined. It could be shown that the three avian Haemophilus-like taxa have to be regarded as new species within the family Pasteurellaceae not affiliated with the recognized genera Actinobacillus, Haemophilus and Pasteurella. H. paragallinarum must be excluded from the genus Haemophilus because of its closer relationship to the actinobacilli. All strains investigated can be differentiated from each other and from recognized species of Pasteurellaceae using an appropriate set of biochemical tests.