Virulence Genes of Helicobacter pylori in Gastritis, Peptic Ulcer and Gastric Cancer in Laos

Background: Helicobacter pylori (H. pylori) infection is an established cause of peptic ulcers and gastric cancer.The aim of this study was to identify H. pylori genotypes and to examine their associations with geographicalregions and gastritis, peptic ulcers and gastric cancer in Laos. Materials and
Methods: A total of 329 Lao dyspepticpatients who underwent gastroscopy at Mahosot Hospital, Vientiane, Laos during December 2010 - March 2012were enrolled. Two biopsy specimens (one each from the antrum and corpus) were obtained for CLO testing andonly CLO test-positive gastric tissue were used to extract DNA. PCR and sequencing were identified for variantsof the cagA and vacA genotypes.
Results: Some 119 Laos patients (36.2%) were found to be infected with H. pyloriincluding 83 with gastritis, 13 with gastric ulcers (GU), 20 with duodenal ulcers (DU) and 3 with gastric cancer.cagA was detected in 99.2%. East-Asian-type cagA (62%) and vacA s1c (64.7%) were predominant genotypes inLaos. vacA s1c-m1b was significantly higher in GU than gastritis (53.8% vs. 24.1%; P-value=0.04) whereas vacAs1a-m2 was significantly higher in DU than gastritis (40.0% vs. 16.9%; P-value=0.03). East-Asian-type cagA andvacA s1c were significantly higher in highland than lowland Lao (100% vs. 55.8%; P-value=0.001 and 88.2% vs.61.5%, P-value=0.03 respectively).
Conclusions: H. pylori is a common infection in Laos, as in other countriesin Southeast Asia. The cagA gene was demonstrated in nearly all Laos patients, cagA and vacA genotypes beingpossible important factors in explaining H. pylori infection and disease outcomes in Laos.