DETECTION OF VIRULENCE GENE CagA OF HELICOBACTER PYLORI FROM GASTRIC JUICE BY SEMI-NESTED-PCR

Abstract

CagA (Cytotoxin-associated gene A) was the first virulence gene characterized in H. pylori. CagA gene encodes a protein involved in increasing gastritis, which can cause serious damage to the lining of the stomach and promote the development of stomach cancer. Accurate diagnosis of H. pylori strains carrying gene CagA is important in screening for the risk of gastric cancer. Currently, PCR is still the most used method to determine the presence of CagA genes in H. pylori strains. However, this method still faces some difficulties in the case of specimens containing small amounts of H. pylori, or contaminant samples. In this study, we established a Semi-Nested-PCR reaction to detect directly H. pylori strains carrying the CagA gene from gastric juice samples to reduce invasiveness compared to analytical methods from gastric tissue. This study showed that the established Semi-Nested PCR reaction allowed for specific amplification of the CagA gene from the control strains as well as from patient samples. Analysis of 35 samples showed that the percentage of CagA gene positive strains accounted for a high rate, up to 90%.