Occurrence of sialidase and N-acetylneuraminate lyase in Pasteurella species

Pasteurella species and related taxa are opportunistic pathogens parasitizing on mucous membranes of higher organisms containing sialic acids. Therefore, sialidase is a virulence factor which up to now has been described to be present in P. haemolytica, P. multocida, and P. volantium. Because of some taxonomic changes and the description of many new species or still unnamed groups, the presence of sialidase and the metabolic successor enzyme, N-acetylneuraminate lyase, was investigated in 65 Pasteurella or Pasteurella-like strains. The detection of enzymes was performed by colorimetry, by paper chromatography and immunoelectrophoresis. Using bovine submaxillary mucin as substrate, sialidases were produced in all strains studied although the activities were different. Most strains but not all were positive in N-acetylneuraminate lyase, too. Taken together, the strains of Pasteurella sensu stricto showed the strongest activities of sialidase, those of the Pasteurella aerogenes complex the lowest. However, because of loss of sialidase activity during subcultivation, there is little feasibility to characterize Pasteurella species by these enzymes.