TARGETED MUTAGENESIS OF THE PHOSPHOLIPASE-D GENE RESULTS IN DECREASEDVIRULENCE OF CORYNEBACTERIUM-PSEUDOTUBERCULOSIS

The chromosomal gene encoding the phospholipase D from Corynebacterium pseodotuberculosis (biovar ovis) isolate Whetten 1 was replaced with an allele containing a nonsense mutation. The virulence of the mutant strain (W1.31r1) and the isogenic parental strain were then compared b y inoculation of goats. The wild-type strain caused abscessation at th e site of infection, which then spread to the regional lymph node, whi le W1.31r1 had a reduced ability to establish a primary infection and was incapable of dissemination. Our results confirm that phospholipase D is a virulence determinant of C. pseudotubercolosis that increases the persistence and spread of the bacteria within the host.