Geographic distribution of vacA allelic types of Helicobacter pylori

Correlation of Helicobacter pylori Genotypes with Gastric Histopathology in the Central Region of a South-European Country

“…The vacA s2m2 genotype is apparently less common and another study in Portugal, performed in patients submitted to a screening program, revealed a prevalence of 29.7 % for such allele combination (42.9 % if multiple vacA genotypes were excluded). The vacA s2m2 prevalence found in our study is among the highest reported [24]. This was expected given the high prevalence of cagA negative strains and the association of such genetic profile with vacA s2 and vacA m2 [24].…”

“…H pylori exceptional genetic variability and intraspecies diversity contributes to this discrepancy [23]. There is a geographic variability of H. pylori genotypes [20,24]. Patients infected with more virulent strains have higher probabilities of developing complications [5].…”

“…There were no cases of gastric carcinoma. Van Doorn et al [24] also presented a prevalence of cagA-positive strains of only 35.7 % in Egypt, where most of the isolates were from non-ulcer patients. Another possible explanation is that there is a national and regional heterogeneity in distribution of H. pylori genotypes and in the Central region of Portugal cagA negative strains might be more common.…”

“…There are clear geographic differences in the distribution of both vacA s and m subtypes [24,33]. The H. pylori vacA s1m1 genotype is the most common in American, European and East Asian countries [24,29,[41][42][43].…”

“…The H. pylori vacA s1m1 genotype is the most common in American, European and East Asian countries [24,29,[41][42][43]. The vacA s2m2 genotype is apparently less common and another study in Portugal, performed in patients submitted to a screening program, revealed a prevalence of 29.7 % for such allele combination (42.9 % if multiple vacA genotypes were excluded).…”