Abstract
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 and biopsies 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 s1 m1 was the most prevalent [56.4% (132)] followed by s2 m2 [11.5% (27)], s2 m1 [10.3% (24)] and [s1 m2 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.
Highlights
Patient recruitment Patients were recruited in the gastrointestinal tract (GIT) unit of the Chris Hani Baragwanath Academic Hospital (CHBAH) between August 2017 and February 2018
Ninety-eight (85.2%) of the patients positive for culture were detected in polymerase chain reaction (PCR), giving an overall prevalence of 52.7% (i.e. 234/444) (Fig. 1)
Our study showed vacuolating cytotoxin gene A (vacA) s1 to be predominant, which is similar to findings reported elsewhere such as Eastern Cape South Africa [41], Thailand [29] and Indian [20]
Summary
The 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. The global prevalence of H. pylori approaches 50% (approximately 4.4 billion individuals infected), with prevalence rates between 20 and 40% in developed countries and up to 90% in Africa and other developing nations of the world [1]. The smoking of cigarette, alcohol consumption, diet, occupational exposure, individual genetic trait have been demonstrated as risk factors associated with infection of H. pylori [8]. Oftentimes the results are inconsistent, with some studies indicating no difference in prevalence compared to a control group [9], while others display a lower or a higher prevalence [10, 11]
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