Unveiling the prevalence of Helicobacter pylori CagA and VacA virulence markers in Moroccan children and adolescents

Abstract

Purpose: Heterogeneity in the vacA and cagA pathogenicity factors of Helicobacter pylori has been correlated with the progression and the severity of gastrointestinal disease in adults; however, data regarding these markers in the pediatric population remain limited. The objective of this research was to assess the distribution of the vacA and cagA virulence markers in symptomatic Moroccan children and adolescents, as well as their association with histologic and endoscopic findings.

Materials and methods: Gastric tissue samples were retrieved from two hundred children and adolescents referred for upper gastrointestinal endoscopy. Conventional PCR was employed to detect H. pylori infection and the presence of the cagA gene, whereas multiplex-PCR was used to characterize the vacA allelic variants (s and m alleles).

Results: From the 200 children and adolescents involved in this research, 84,5% tested positive for H. pylori. Among these,32% carried the cagA gene, and vacA was identified in all H. pylori strains. The most prevalent gnotype combination was the vacA s2/m2 genotype, affecting 67.5% of the infected patients, followed by s1/m2 (16%), s1/m1 (14.7%), with the vacA s2/m1 being the rarest genotype (1.8%). Gastric nodularity was frequently observed in patients harboring cagA-positive strains. A meaningful association was noted between H. pylori colonisation density and the vacA s1 and m1 genotypes. Histological findings showed no significant variation according to vacA and cagA genotypes.

Conclusion: Our results showed that H. pylori strains harboring the vacA s2 m2 and cagA-negative genotypes were the most frequently detected among children and adolescents in our country. Larger-scale studies are needed to investigate the potential clinical relevance of other virulence markers in the progression of this infection among pediatric patients in our country.