Prevalence of Helicobacter pylori cagA and vacA allelic variants and associated disease outcomes in Kenyan patients with dyspepsia

Abstract

Although Helicobacter pylori has been linked to various gastric disorders in Western countries and Asia, its aetiopathological role in African populations is controversial. The aim of this study was to investigate the role of H. pylori and its virulence genotypes in gastrointestinal diseases in Kenyan patients with dyspepsia. Gastric biopsy specimens were obtained for DNA isolation and histopathological analysis. Amplifcation was performed using specifc oligonucleotide primers. H. pylori positivity was determined by H. pylori stool antigen test, rapid urease test, and histology and molecular diagnostic tools. H. pylori was detected with high frequency in patients with gastritis, peptic ulcer disease (PUD) and gastro-oesophageal refux disease. This implies a signifcant risk of the development of these pathologies (p-value = 0.0000 in all cases). H. pylori strains with cagA occurred more frequently in PUD (65.2%). vacA s1a genotype appeared to play a more signifcant pathological role (82.6% PUD) than the other variants (p-value = 0.0142). The prevalence of vacA m1 was signifcantly higher in gastritis cases (p-value = 0.0253). vacA m2 was found to be signifcantly associated with gastritis (p-value = 0.0253). This fnding may point to the fact that H. pylori vacA m1 and vacA m2 are independently associated with an increased risk for gastritis. Indications are that H. pylori prevalence in Kenya may be declining. The independently occurring H. pylori genotypes, as opposed to simultaneous carriage, could be the reason for the low distribution of H. pylori pathologies.