Cj0596 is a periplasmic peptidyl prolyl cis-trans isomerase involved in Campylobacter jejuni motility, invasion, and colonization

Abstract

Abstract Background Campylobacter jejuni is a gastrointestinal pathogen of humans, but part of the normal flora of poultry, and therefore grows well at the respective body temperatures of 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 involved in outer membrane protein folding and virulence in other bacteria. Results The cj0596 gene was highly conserved in 24 strains and species of Campylobacter, implying the importance of this gene. To study the role that Cj0596 plays in C. jejuni pathogenesis, a mutant derivative of strain 81–176 was constructed in which the cj0596 gene was precisely deleted. A revertant of this mutant was isolated by restoring the gene to its original chromosomal location using streptomycin counterselection. The cj0596 mutant strain demonstrated a slightly decreased growth rate and lower final growth yield, yet was more motile and more invasive of human intestinal epithelial cells than wild-type. In either single or mixed infections, the mutant was less able to colonize mice than 81–176. The cj0596 mutant also expressed altered levels of several proteins. Conclusion Mutation of cj0596 has an effect on phenotypes related to C. jejuni pathogenesis, probably due to its role in the proper folding of critical outer membrane proteins.