Detection of Helicobacter pylori and its virulence genes (cagA, dupA, and vacA) among patients with gastroduodenal diseases in Chris Hani Baragwanath Academic Hospital, South Africa

BackgroundThe global prevalence of H. pylori approaches 50%, with prevalence rates between 20 and 40% in developed countries and up to 90% in Africa and other developing nations of the world. Development of H. pylori-associated diseases is determined by a number of virulence factors. This study aimed at determining the prevalence of H. pylori infections and virulence genes (cagA, dupA, and vacA); the relationship between virulence factors and gastroduodenal diseases among patients.MethodsGastric biopsies were obtained from patients and cultured, DNA was extracted from cultured isolates andbiopsies for PCR assay after which samples were investigated using standard laboratory procedures. Data of associated risk factors were obtained with the aid of questionnaires.ResultsOf the 444 participants, H. pylori was detected in 115 (25.9%) from culture analysis and 217 (48.9%) by direct PCR method. Ninety-eight (85.2%) of the culture-positive patients were also detected by PCR giving an overall prevalence of 52.7% (234/444). The highest number of H. pylori isolates 76.9% (180/234) was obtained from patients suffering from pangastritis. The CagA virulence gene was found in 62% (145/234), dupA in 53.4% (125/234) and vacA in 90.6% (212/234). VacA genotype s1m1 was the most prevalent [56.4% (132)] followed by s2m2 [11.5% (27)], s2m1 [10.3% (24)] and [s1m2 9.4% (22)]. There was a significant association observed in vacA s1 and peptic ulcer disease, as well as vacA s1/m2 and gastric erosion (P<0.05).ConclusionThe study revealed a significant association between virulence genes and the development of certain forms of gastric infections while the variations in H. pylori detection and the associated risk factors investigated in the study were not significantly related.