96 plays a role in the virulence of C. jejuni

Abstract

Campylobacter jejuni is a gastrointestinal pathogen of humans but part of the normal flora of poultry. C. jejuni therefore grows well at both 37°C and 42°C. Proteomic studies on temperature regulation in C. jejuni strain 81-176 revealed the upregulation at 37°C of CJ0596, a predicted periplasmic chaperone that is similar to proteins found to be involved in outer membrane protein (OMP) folding and virulence in other bacteria. The cj0596 gene was highly conserved in multiple strains and species of Campylobacter (24 in total), implying the importance of this gene. To study the role CJ0596 plays in Campylobacter pathogenesis, a mutant derivative of strain 81-176 was constructed in which the cj0596 gene was precisely deleted. This mutant was complemented by restoring the gene to its original chromosomal location. The mutant strain demonstrated a decreased growth rate and lower final growth yield, yet was more motile than wild-type. The cj0596 mutant also showed altered levels of several outer membrane proteins (OMPs), and changes in membrane-associated characteristics (antimicrobial sensitivity, autoagglutination, and biofilm formation). In either single or mixed infections, the mutant was less able to colonize mice than wild-type. Purified, recombinant CJ0596 had peptidyl-prolyl cistrans isomerase (PPIase) activitty, but did not functionally complement an E. coli surA mutant. These results suggest that C. jejuni CJ0596 is a PPIase and loss of CJ0596 alters phenotypes that have been shown to be related to the pathogenesis of the bacterium.