The aim of this study was to determine the presence of Helicobacter pylori
cytotoxin-associated gene (cag
A)/vacuolating cytotoxin gene (vac
A) among patients with chronic gastritis in Cuba and Venezuela.
Gastric antrum biopsies were taken for culture, DNA extraction and PCR analysis. Amplification of vac
A and cag
A segments was performed
using two regions of cag
A: 349 bp were amplified with the F1/B1 primers and the remaining 335 bp were amplified with the B7629/B7628 primers.
The VA1-F/VA1-R set of primers was used to amplify the 259-bp (s1) or 286-bp (s2) product and the VAG-R/VAG-F set of primers was used to
amplify the 567-bp (m1) or 642-bp (m2) regions of vac
A was detected in 87% of the antral samples from Cuban patients and
80.3% of those from Venezuelan patients. All possible combinations of vac
A regions were found, with the exception of s2/m1.
The predominant combination found in both countries was s1/m1. The percentage of cag
strains was increased by the use of a second
set of primers and a greater number of strains was amplified with the B7629/B7628 primers in the Cuban patients (p = 0.0001).
There was no significant difference between the presence of the allelic variants of vac
A and cag
A in both populations.
The predominant genotype was cag
/s1m1 in both countries. The results support the necessary investigation of isolates circulating among
the human population in each region.