Prevalence of Helicobacter pylori vacA, cagA, iceA and oipA genotypes in Tunisian patients

Khansa Ben Mansour,Nabil Ben Mami,Taoufik Najjar,Meriem Zribi,Chédlia Fendri,Ahmed Meherzi,Afef Masmoudi,Tahar Sfar,Azza Fillali,Christophe Burucoa,Mounir Labbene

doi:10.1186/1476-0711-9-10

Abstract

BackgroundDistinct virulence factors of H. pylori have been described: the vaculating cytotoxin (vacA), the cytotoxin associated gene (cagA), the induced by contact with epithelium factor Antigen (iceA gene) and the outer membrane protein oipA. In Tunisia, there are no data regarding the pattern of H. pylori genotypes; therefore, this prospective and multicentre study was the first to be done in Tunisia and aimed to investigate the prevalence of the vacA, cagA, iceA and oipA genotypes of H. pylori isolates from Tunisian patients with peptic ulceration, gastric cancer, MALT lymphoma and gastritis.MethodsH. pylori was cultured from endoscopic biopsies obtained from 281 Tunisian patients. The vacA alleles, cagA, iceA and oipA genotypes were determined by PCR.ResultsThe vacA s1m1, s1m2 and s2m2 were respectively found in 10.7%, 12.5% and 45.6% of strains. The s2m1 genotype was not detected in our study. The cagA was found in 61.6% of isolates. The iceA1 and the iceA2 genotypes were respectively isolated in 60.2% and in 16% of strains. The oipA genotype was detected in 90.8% of strains. Considering the vacA and iceA genotypes, the presence of multiple H. pylori strains in a single biopsy specimen was found respectively in 31.4% and 23.8%. The comparison between strains isolated from antrum and fundus showed that Tunisian patients were infected with two or more strains of different cagA, vacA, iceA and oipA genotypes and the discordance was respectively in 9.6%, 4.6%, 8.9% and 8.5% of strains.ConclusionOur results showed that in 46% (131 strains among 281), the H. pylori strains were highly virulent in relation of the three or four virulent factors they could carry. These finding were described before in the literature. Tunisian patients were colonized by one or multiple strains of H. pylori in the same time in relation of presence of vacA m1/m2 and iceA1/iceA2 in the same biopsy. The discordance between strains isolated from antrum and fundus was high, and it is in favour of multicolonization.

Highlights

Distinct virulence factors of H. pylori have been described: the vaculating cytotoxin, the cytotoxin associated gene, the induced by contact with epithelium factor Antigen and the outer membrane protein oipA
Comparing with strains isolated from patients having gastritis, we found that the prevalence of genotypes vaculating cytotoxin (vacA) s1/cagA+, vacA s1/iceA1 and vacA s1/oipA+ was 11.2%, 10.3%, and 16.8%, respectively
First, we have studied the relationship between virulence genes and the different gastroduodenal diseases, between the two groups

Summary

Introduction

Distinct virulence factors of H. pylori have been described: the vaculating cytotoxin (vacA), the cytotoxin associated gene (cagA), the induced by contact with epithelium factor Antigen (iceA gene) and the outer membrane protein oipA. Strains carrying the s1ml mosaic combination of the gene vacA exhibit higher levels of cytotoxic activity than s1m2 strains, while s2m2 strains do not secrete the vacuolating cytotoxin [12]. Another virulence gene designated iceA (for induced by contact with epithelium) has been recently described. A novel putative virulence factor has been identified, the oipA (outer inflammatory protein) gene, which encodes one of the outer membrane proteins and is an inflammation-related gene located approximately 100 kb from the cag PAI on the H. pylori chromosome [20]. oipA induces IL-8 secretion by epithelial cells and active OipA protein production may be “on” or “off” depending on the number of CT dinucleotide repeats in the signal sequence of the oipA gene (HP0638) [21]

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Results

Conclusion