Host-specific bacterial lineages in the taxon 2 and 3 complex of Pasteurellaceae

The aim of the investigation was to determine the genetic relationship of a phenotypically diverse strain collection of epidemiologically unrelated strains from the taxon 2 and 3 complex of Bisgaard isolated from different hosts. A total of 325 isolates belonging to the taxon 2 and 3 complex of Bisgaard was characterized phenotypically in 82 characters. The genetic relationship among a subset of 60 isolates was investigated by amplified fragment length polymorphism (AFLP). The isolates were selected aiming at including the broadest diversity with regards to phenotype and host spectrum. The results suggested a statistically clear association between AFLP clusters and the host species families Columbidae (pigeon, dove), Anatidae (duck, goose) and Psittacidae (parrot, parakeet, budgerigar), respectively. This association was further supported by results from previous whole cell protein profiling and DNA:DNA hybridization studies.In conclusion, it appears that distinct genetic lineages within the taxon 2 and 3 complex of Bisgaard have evolved specificity for host bird species of different families. The observed host specificity of taxon 2 and 3 organisms may be used in future diagnostics and studies elucidating aspects of pathogenicity and epidemiology associated with the different lineages and their respective hosts.