Generation of Histophilus somni Mutants Deficient in Biofilm Formation or Attenuated in Virulence

Abstract

Histophilus somni is an etiologic agent of bovine respiratory disease and various systemic diseases. A variety of virulence factors have been identified in H. somni, such as the lipooligosaccharide phase variation, the filamentous hemagglutinin, biofilm formation, and others, which act primarily to protect the pathogen against host defense mechanisms. Thorough investigation of the role of these virulence factors has been compromised because mutagenesis of H. somni using allelic exchange is difficult due to the apparently tight restriction modification system in virulent strains.