Abstract
Introduction: CagA and VacA are the most important and well-studied virulence factors found in Helicobacter pylori. The aim of this work was to identify genes corresponding to H. pylori pathogenicity factors in Brazzaville, Congo. Material & Methods: A cross-sectional study was carried out from October 2013 to December 2016. Biopsy specimens were obtained from patients scheduled for upper gastrointestinal endoscopy in Brazzaville, Congo and were sent to the French National Reference Center for Campylobacters and Helicobacters in Bordeaux, France. H. pylori detection was conducted by real-time PCR using a fuorescence resonance energy transfer-melting curve analysis protocol. The identification of the genes encoding pathogenicity factors was carried out by conventional PCR using the appropriate primers for determination of CagA phosphorylation motifs 1, 2, 3; and vacAs, I and m regions: vacAi1, vacAi2, vacAs1a, vacAs1b. Results: A high prevalence of H. pylori infection was reported (108/143; 75.5%). In 92.2% (n = 71/77), the presence of P1, P2 and P3 CagA phosphorylation motifs was noted. Concerning vacA, vacAs1m1 was observed in 82% of the strains (n = 59/72). vacAi1 was present in all strains (n = 76). With regard to the distribution according to the vacAs1 subtype, the majority of the strains (59/71; 83%) were vacAs1b positive, as compared to vacAs1c (17/34, 33%). The vacAs1a gene was absent in all of these patients. Conclusion: The presence of genes associated with severe gastric diseases indicates the importance of H. pylori eradication in the prevention of these diseases in Congo.
Highlights
CagA and VacA are the most important and well-studied virulence factors found in Helicobacter pylori
The identification of the genes encoding pathogenicity factors was carried out by conventional PCR using the appropriate primers for determination of CagA phosphorylation motifs 1, 2, 3; and vacAs, I and m regions: vacAi1, vacAi2, vacAs1a, vacAs1b
The presence of genes associated with severe gastric diseases indicates the importance of H. pylori eradication in the prevention of these diseases in Congo
Summary
CagA and VacA are the most important and well-studied virulence factors found in Helicobacter pylori. The aim of this work was to identify genes corresponding to H. pylori pathogenicity factors in Brazzaville, Congo. The identification of the genes encoding pathogenicity factors was carried out by conventional PCR using the appropriate primers for determination of CagA phosphorylation motifs 1, 2, 3; and vacAs, I and m regions: vacAi1, vacAi2, vacAs1a, vacAs1b. Conclusion: The presence of genes associated with severe gastric diseases indicates the importance of H. pylori eradication in the prevention of these diseases in Congo. At least 10% of infected individuals develop PUD, and 1% - 3% develop gastric cancer [1]. The gastric cancer risk in H. pylori infected people is 2 to 7 times that of the uninfected. The WHO classified H. pylori as a group I carcinogen in 1994 (ref IARC) which they reconfirmed later [2]
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