Abstract
BackgroundThe babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations. This study was aimed to understand the role of babA2 of H. pylori with the background of cagA and vacA in disease manifestations in Indian sub population.MethodsA total of 114 H. pylori strains isolated from duodenal ulcer (DU) (n = 53) and non-ulcer dyspepsia (NUD) patients (n = 61) were screened for the prevalence of these virulence markers by PCR. The comparative study of IL-8 production and apoptosis were done by co-culturing the AGS cell line with H. pylori strains with different genotypes. Adherence assay was performed with babA2 positive and negative strains. Two isogenic mutants of babA2 were constructed and the aforesaid comparative studies were carried out.ResultsPCR results indicated that 90.6 % (48/53), 82 % (50/61) and 73.6 % (39/53) strains from DU patients were positive for cagA, vacA, and babA2, respectively. Whereas the prevalence of these genes in NUD subjects were 70.5 % (43/61); 69.8 % (37/53), and 65.6 % (39/61), respectively. Although adherence to AGS cells was comparable among strains with babA2 positive and negative genotypes, but the triple positive strains could induce highest degree of IL-8 production and apoptosis, followed by the cagA−/vacA−/babA2+ strains and triple negative strains, respectively. The wild type strains showed significantly higher IL-8 induction as well as apoptosis in ex vivo than its isogenic mutant of babA2.ConclusionPCR study demonstrated that there was no significant association between the distribution of babA2 genotype or of triple positive strains and disease outcome in this sub population. The adherence assay showed that there was no significant difference in the extent of adherence to AGS cells among babA2 positive and negative strains. But the ex vivo study indicated that the triple positive or even the babA2 only positive strains are involved in increased virulence. The wild type strains also exhibited increased virulence compared to the babA2 mutant strains. This inconsistency demonstrated that bacterial genotype along with host genetic polymorphisms or other factors play important role in determining the clinical manifestation of H. pylori infections.
Highlights
The babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations
Acidity, loss of appetite but no frank ulceration were considered as non-ulcer dyspepsia (NUD) but those have endoscopically visible duodenal ulceration were considered as duodenal ulcer (DU) patients
On the basis of the combined results with these three sets of primers, our analysis depicted that 67.5 % (77/114) Indian H. pylori strains were positive for babA2 gene (Table 1)
Summary
The babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations. This study was aimed to understand the role of babA2 of H. pylori with the background of cagA and vacA in disease manifestations in Indian sub population. Helicobacter pylori is a Gram-negative, genetically diverse spiral bacteria that infects more than half of the. Genetic variation in specific virulence genes of H. pylori may participate in the pathogenic process of H. pylori infection in the stomach, thereby contributing to the variable risk of diverse clinical outcomes. About one-half to two-thirds of US and European strains carry the cag PAI and is associated with overt disease. It was found that most of the H. pylori strains in Indian subcontinent have cagA typeA and any particular type of cagA is not associated with disease outcome [11]
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