VacA genotyping directly from gastric biopsy specimens and estimation of mixed Helicobacter pylori infections in patients with duodenal ulcer and gastritis.

BACKGROUND

The vacA genotypes and the cagA gene status were investigated in 80 Helicobacter pylori-infected patients with duodenal ulcer (DU) and 49 with gastritis only.

METHODS

Lysates of gastric biopsy specimens were used directly for polymerase chain reaction-based detection.

RESULTS

The ml subtype was found in 36% and 31% and the m2 in 36% and 46% of specimens from patients with DU and gastritis, respectively (P > 0.05). In 15% of samples the midregion remained unclassified. The prevalence rate of s1 subtypes was higher in cases of DU (69%) than in gastritis (43%) (P < 0.0001); the opposite correlation was observed for s2. The cagA gene was detected in 80% of patients with DU and in 52% of those with gastritis (P < 0.0001). Infections with multiple H. pylori strains exceeded 50% in both groups.

CONCLUSIONS

These results suggest that vacA s1 genotype and cagA+ status are associated with higher DU prevalence and that mixed H. pylori infections are very common in our geographic region.