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

Abstract

Background 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 ( cag A , dup A , and vac A); the relationship between virulence factors and gastroduodenal diseases among patients. Methods Gastric 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. Results Of 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 Cag A virulence gene was found in 62% (145/234), dup A in 53.4% (125/234) and vac A in 90.6% (212/234). Vac A 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 vac A s1 and peptic ulcer disease, as well as vac A s1/m2 and gastric erosion ( P < 0.05). Conclusion The 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. Electronic supplementary material The online version of this article (10.1186/s12876-019-0986-0) contains supplementary material, which is available to authorized users.

Helicobacter pyloriInfection, Virulence Genes’ Distribution and Accompanying Clinical Outcomes: The West Africa Situation

“…The study, however, concluded that no association existed between the studied genotypes and duodenal ulcer disease in that particular population [139]. These reported observations on prevalence are consistent with studies in India (96% among duodenal ulcer patients), [140] Gauteng (87% among asymptomatic children age between 6 and 15 years), [141] Alaskans-US (85%), [142] China (89.3% in patients with upper gastrointestinal diseases), and Taiwan (83% in isolates from patients with chronic gastritis and peptic ulcer) [143]. Another report in Nigeria by Mnena et al [86], however, identified only 29% out of 22 H. pylori positive patients to have the cagA gene.…”

“…In Nigeria, Smith et al detected 98% of vacA s1 in 40 H. pylori strains [139] while Harrison et al found 92.8% detectable vacA levels [61] similar to the 90.6% obtained in South Africa [141]. In the study by Harrison et al, a bulk of the isolates harbored the vacA s1, m2 genotype, followed by the s1, m1 genotype.…”

Antibiotic Resistance and Genotypes of Helicobacter pylori Strains in Patients with Gastroduodenal Disease in Southeast Poland

“…The vacA genotypes (allelic variations) are significantly different in each country and previous studies have confirmed important geographic differences in these virulence factors [27,28,29]. Among different genotypes, infection with H. pylori strains containing vacA s1m1 type was strongly associated with increased risk of gastric cancer or PUD [8,30,31]. In our study, most frequent allelic combination of vacA gene were s1am2 —38.7% and s2m2 —32.3%, that was similar to previous Polish studies [23,24,32]; however, statistically significant associations between vacAs1m1 type and GAST and PUD patients were observed ( p = 0.042 and p = 0.038, respectively).…”

Novel virulence factor dupA of Helicobacter pylori as an important risk determinant for disease manifestation: An overview

“…In the northern part of Spain, dupA was more prevalent in mild diseases (peptic ulcer) than severe diseases (GC)[ 62 ]. In Switzerland and South Africa, dupA of H. pylori was not associated with severe gastritis or DU[ 63 , 64 ].…”