Detection of vacA gene alleles frequency in Helicobacter pylori strains from patients with gastric diseases in Zliten city Libya

Abstract

Helicobacter pylori  (H. pylori) has worldwide distribution, leading to various gastric diseases, including chronic gastritis, peptic ulcer and gastric cancer. A vacA gene, which encodes a vacuolating cytotoxin is one of the most known virulence gene of the bacterium. The aim of this study was to evaluate the most common vacA alleles (s1 and s2) in H. pylori strains isolated from Libyan patients and its relationship with ages and gastritis lesions. Gastric biopsies were obtained from patients for DNA  extraction. vacA genotypes were analyzed by PCR and agarose electrophoresis. s1 and s2 genotypes were also confirmed by DNA sequencing. The allele s2 occurred in 81% of the all examined group, which represent the most frequently observed of the signal encoding region. Whereas s1 genotype had the lowest frequency 19%. Statistically significant differences in s1 and s2 alleles  in relation to a ages were not detected. This study showed that there was a relationship between the presence of vacA gene and progression of gastritis. the predominant vacA gene alleles in Zliten city is s2 allele.