Secretion of proteases from Pasteurella multocida isolates

The capability of Pasteurella multocida to secrete proteases to the culture medium and their characterization were studied in five animal isolates (bo vine, chicken, sheep, and two from pig). All the isolates produced protease s in a wide range of molecular mass. It is suggested that they are neutral metalloproteases, since they were optimally active between pH 6 and 7, inhi bited by chelating agents but not by other protease inhibitors, and reactiv ated by calcium. Proteases from isolates were able to degrade IgG. Several proteins from supernatants of cultures precipitated with 70% (NH4)(2)SO4 of all the P. multocida isolates were recognized by a polyclonal antiserum ra ised against a purified protease from Actinobacillus pleuropneumoniae. Prot ease production might play an important role during tissue colonization and in P. multocida diseases.