Essential Role of Invasin for Colonization and Persistence of Yersinia enterocolitica in Its Natural Reservoir Host, the Pig

Abstract

ABSTRACTIn this study, an oral minipig infection model was established to investigate the pathogenicity ofYersinia enterocoliticabioserotype 4/O:3. O:3 strains are highly prevalent in pigs, which are usually symptomless carriers, and they represent the most common cause of human yersiniosis. To assess the pathogenic potential of the O:3 serotype, we compared the colonization properties ofY. enterocoliticaO:3 with O:8, a highly mouse-virulentY. enterocoliticaserotype, in minipigs and mice. We found that O:3 is a significantly better colonizer of swine than is O:8. Coinfection studies with O:3 mutant strains demonstrated that small variations within the O:3 genome leading to higher amounts of the primary adhesion factor invasin (InvA) improved colonization and/or survival of this serotype in swine but had only a minor effect on the colonization of mice. We further demonstrated that a deletion of theinvAgene abolished long-term colonization in the pigs. Our results indicate a primary role for invasin in naturally occurringY. enterocoliticaO:3 infections in pigs and reveal a higher adaptation of O:3 than O:8 strains to their natural pig reservoir host.