The Prevalence and Polymorphisms of Zonula Occluden Toxin Gene in Multiple Campylobacter concisus Strains Isolated from Saliva of Patients with Inflammatory Bowel Disease and Controls

Vikneswari Mahendran,Michael C Grimm,Sophie Octavia,Li Zhang,Ye Sing Tan,Daniel A Lemberg,Andrew S Day,Ruiting Lan,Stephen M Riordan,Georgina L Hold

doi:10.1371/journal.pone.0075525

Vikneswari Mahendran, Michael C Grimm + Show 8 more

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https://doi.org/10.1371/journal.pone.0075525

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Abstract

Campylobacter concisus is an oral bacterium. A number of studies detected a significantly higher prevalence of C . concisus in the intestinal tract of patients with inflammatory bowel disease (IBD) as compared to controls. The prevalence of zonula occluden toxin (zot) gene, which encodes a toxin known to increase intestinal permeability, in oral C . concisus strains is unknown. Increased intestinal permeability is a feature of IBD. A total of 56 oral C . concisus strains isolated from 19 patients with IBD and 20 controls were examined (some individuals were colonized with multiple strains). A filtration method was used for isolation of C . concisus from saliva samples. SDS-PAGE was used to define strains. PCR was used to amplify zot from C . concisus strains. Positive PCR products were sequenced and the nucleotides and amino acids were compared. Of the 56 oral C . concisus strains examined, 17 strains (30.4%) were positive for zot. The prevalence of zot-positive oral C . concisus strains was 54.5% in patients with active IBD, which was not significantly different from that in healthy controls (40%). Polymorphisms of C . concisus zot were revealed. zot 808T , zot 350-351AC and zot Multiple were detected only in patients with IBD, but not in healthy controls. Both zot 808T and zot Multiple alleles resulted in substitution of valine at position 270, which occurred in 36.4% of patients with active IBD but not in healthy controls (P = 0.011). Furthermore, the prevalence of multiple oral C . concisus strains in patients with active IBD was significantly higher than that in healthy controls (P = 0.013). This is the first study reporting the prevalence of zot in human oral C . concisus strains and the polymorphisms of C . concisus zot gene. The data suggest that the possible role of C . concisus strains containing specific polymorphic forms of zot gene in human IBD should be investigated.

Highlights

Increased Campylobacter concisus intestinal colonization has been associated with inflammatory bowel disease (IBD)
These 401 C. concisus isolates were shown to represent 50 different strains, with each strain showing a distinct whole cell protein profile on SDS-PAGE. These 50 oral C. concisus strains and the six oral C. concisus strains previously isolated from three patients with IBD and a healthy control were included in this study [12]
The prevalence of multiple oral C. concisus strains in patients with active IBD was 63.6% (7/11), which was significantly higher than that in healthy controls 15% (3/20) in healthy controls (P = 0.013)

Summary

Introduction

Increased Campylobacter concisus intestinal colonization has been associated with inflammatory bowel disease (IBD). A number of studies have detected a significantly higher prevalence of C. concisus in fecal samples and intestinal biopsies collected from patients with IBD as compared to controls [2,3,4,5]. We found that some patients with IBD are colonized with multiple C. concisus strains in the oral cavity and intestinal tract [12]. Increased intestinal epithelial apoptosis and permeability by some C. concisus strains have been previously reported [13,14,16] These data suggest that some oral C. concisus strains may have the potential to cause enteric diseases in individuals whose intestinal environment is suitable for C. concisus colonization. We have examined the prevalence of the zot gene in multiple C. concisus strains isolated from saliva samples of patients with IBD and controls. The polymorphisms of C. concisus zot gene were examined

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