Re-investigations of selected bovine and ovine strains previously classified as Pasteurella haemolytica and description of some new taxa within the Pasteurella haemolytica-complex.

The taxonomic relationship of 116 isolates of Pasteurella haemolytica was re-investigated by conventional phenotypic characterization. Seventy-nine characters were examined. Ninety strains were classified with previously described biovars of P. haemolytica. The remaining strains made up at least six new biogroups within the P. haemolytica-complex. "Key-characters" separating these groups included ornithine, L(+)arabinose, D(-)sorbitol, cellobiose, beta-glucosidase, glycosides and alpha-fucosidase. The taxonomic significance of these characters is uncertain. Determinations of genome size, mol% G + C in DNA and DNA:DNA hybridizations are in progress to obtain further information on the taxonomic significance of the present findings.