Identification of toxigenic strains of Pasteurella multocida by PCR and biological methods

Sensitivity and specificity of methods for the identification of toxigenic strains of Pasteurella multocida were compared. The production of dermonecr otoxin was determined by a skin test in guinea pigs, a cell culture test us ing bovine embryonic lung cells, and PCR. The highest sensitivity and speci ficity were found for PCR that allows the identification of strains produci ng only small amounts of the toxin in vitro that are not detectable by biol ogical methods. However, strains producing structurally different toxins wi th the same biological effect are not identifiable by this technique owing to its high specificity. Therefore, biological and particularly cell cultur e tests are necessary for a comprehensive assessment of toxigenicity of ind ividual strains.