Role of Campylobacter jejuni Potential Virulence Genes in Cecal Colonization

Abstract

Campylobacter jejuni, a common commensal in chickens, is one of the leading causes of bacterial gastroenteritis in humans worldwide. The aims of this investigation were twofold. First, we sought to determine whether mutations in the C. jejuni ciaB and pldA virulence-associated genes impaired the organism's ability to colonize chickens. Second, we sought to determine if inoculation of chicks with C. jejuni mutants could confer protection from subsequent challenge with the C. jejuni wild-type strain. The C. jejuni ciaB gene encodes a secreted protein necessary for the maximal invasion of C. jejuni into cultured epithelial cells, and the pldA gene encodes a protein with phospholipase activity. Also included in this study were two additional C. jejuni mutants, one harboring a mutation in cadF and the other in dnaJ, with which we have previously performed colonization studies. In contrast to results with the parental C. jejuni strain, viable organisms were not recovered from any of the chicks inoculated with the C. jejuni mutants. To determine if chicks inoculated with the C. jejuni mutants become resistant to colonization by the C. jejuni parental strain upon subsequent challenge, chicks were inoculated either intraperitoneally (i.p.) or both orally and i.p. with the C. jejuni mutants. Inoculated birds were then orally challenged with the parental strain. Inoculation with the C. jejuni mutants did not provide protection from subsequent challenge with the wild-type strain. In addition, neither the C. jejuni parental nor the mutant strains caused any apparent morbidity or mortality of the chicks. We conclude that mutations in genes cadF, dnaJ, pldA, and ciaB impair the ability of C. jejuni to colonize the cecum, that chicks tolerate massive inoculation with these mutant strains, and that such inoculations do not provide biologically significant protection against colonization by the parental strain.

Characterization of a haemolytic phospholipase A2 activity in clinical isolates of Campylobacter concisus

“…The existence of this sequence similarity suggests that a similar gene sequence for a haemolytic PLA enzyme exists in C. concisus strains assigned to both PCR groups (genomospecies). A pldA mutant of C. coli was previously shown to have marked reduction in haemolytic activity when compared with the wild-type strain, suggesting a role for pldA as a virulence determinant in campylobacters (Grant et al, 1997), while a C. jejuni pldA mutant was reported to have an impaired ability for caecal colonization in chicken (Ziprin et al, 2001). Similar research with a H. pylori pldA mutant has been reported, suggesting that the H. pylori pldA phospholipase has a role in colonization of the gastric mucosa and possible tissue damage after colonization (Dorrell et al, 1999).…”

Campylobacter jejuni infection and virulence-associated genes in children with moderate to severe diarrhoea admitted to emergency rooms in northeastern Brazil

“…Also, CiaB and other secreted proteins require functional flagella export apparatus for their secretion (Konkel et al, 2004;Dasti et al, 2010). The pldA gene encodes a protein involved in the synthesis of an outer membrane phospholipase that has also been related to cellular invasion (Ziprin et al, 2001). The plasmid pVir is associated with the ability of C. jejuni to adhere to and invade cells in vitro and has been shown to increase virulence in vivo (Bacon et al, 2000).…”

PCR Detection of Four Virulence-Associated Genes of Campylobacter jejuni Isolates from Thai Broilers and Their Abilities of Adhesion to and Invasion of INT-407 Cells

“…Some genes are involved in Campylobacter adhesion and invasion. Four mutant strains derived from F38011, an excellent colonizer of chicken caeca, dnaJ, cadF, pldA and ciaB are incapable of colonizing the ceca [20,23,43,44]. cadF (Campylobacter adhesin to fibronectin) is an outer membrane protein, which encodes a protein that interacts with a host extracellular matrix protein fibronectin [31], and is required for Campylobacter adherence to and colonization of the host cell surface [20].…”

“…cadF (Campylobacter adhesin to fibronectin) is an outer membrane protein, which encodes a protein that interacts with a host extracellular matrix protein fibronectin [31], and is required for Campylobacter adherence to and colonization of the host cell surface [20]. Other genes such as ciaB (Campylobacter invasive antigen B) [21,34] and pldA encoded outer membrane phospholipase A [34] are involved in host cell invasion and are important for caecal colonization [21,43]. The ciaB, pldA and dnaJ (heat shock protein) genes are important to caecal colonization and mutations of these genes severely limit the ability of the mutant strains to colonize the chicken caeca [20,43,44].…”

“…Other genes such as ciaB (Campylobacter invasive antigen B) [21,34] and pldA encoded outer membrane phospholipase A [34] are involved in host cell invasion and are important for caecal colonization [21,43]. The ciaB, pldA and dnaJ (heat shock protein) genes are important to caecal colonization and mutations of these genes severely limit the ability of the mutant strains to colonize the chicken caeca [20,43,44]. The objective of this study was to study the prevalence of C. jejuni in Thai broiler caeca and their ability to adhere and invade and the presence of the 4 genes that are involved in the adherence and invasion of the Campylobacter in the INT-407 cell culture model.…”