OCCURRENCE OF [COPPER, ZINC]-COFACTORED SUPEROXIDE-DISMUTASE IN PASTEURELLA-HAEMOLYTICA AND ITS SEROTYPE DISTRIBUTION

Fifty-two ovine strains of Pasteurella haemolytica and P. trehalosi re presenting serotypes 1-16 were examined for the presence of [copper, z inc]superoxide dismutase DNA sequences. This was done using a combinat ion of polymerase chain reaction with degenerate primers based on the sequence of the [Cu,Zn]superoxide dismutase gene (sodC) in related spe cies and Southern hybridization using a fragment of sodC from P. haemo lytica A2 serotype as a probe. Both detection methods identified a fra gment of the sodC gene in 9/9 strains of P. haemolytica serotype 2 exa mined and in 5/8 strains of serotype 7. No evidence of this gene was f ound in any other serotype of P. haemolytica or in any P. trehalosi se rotype. Comparison of DNA sequence showed near identity between sodC f rom the A2 and A7 serotypes of P. haemolytica and substantial similari ty (70%) to sodC previously sequenced in P. multocida, Haemophilus par ainfluenzae and H. influenzae. Analysis by gel electrophoresis of the superoxide dismutase activity present in cell lysates showed that one or more superoxide dismutase is present in all serotypes. However, cya nide-inhibitable activity, corresponding to [Cu,Zn]superoxide dismutas e, was detected only in those strains of serotypes A2 and A7 which sho wed evidence of the sodC gene fragment.