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 geographical regions and gastritis, peptic ulcers and gastric cancer in Laos.


METHODS
A total of 329 Lao dyspeptic patients who underwent gastroscopy at Mahosot Hospital, Vientiane, Laos during December 2010--March 2012 were enrolled. Two biopsy specimens (one each from the antrum and corpus) were obtained for CLO testing and only CLO test-positive gastric tissue were used to extract DNA. PCR and sequencing were identified for variants of the cagA and vacA genotypes.


RESULTS
Some 119 Laos patients (36.2%) were found to be infected with H. pylori including 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 in Laos. vacA s1c-m1b was significantly higher in GU than gastritis (53.8% vs. 24.1%; P-value=0.04) whereas vacA s1a-m2 was significantly higher in DU than gastritis (40.0% vs. 16.9%; P-value=0.03). East-Asian-type cagA and vacA 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 countries in Southeast Asia. The cagA gene was demonstrated in nearly all Laos patients, cagA and vacA genotypes being possible important factors in explaining H. pylori infection and disease outcomes in Laos.
Department of Gastroenterology, Mahosot Hospital, Vientiane, Laos E-mail : vilaichone@hotmail.co.th.
Sengdao
S
Vannarath
Ratha-korn
RK
Vilaichone
Bouachanh
B
Rasachak
Pisaln
P
Mairiang
Yoshio
Y
Yamaoka
Seiji
S
Shiota
Tran Thanh
TT
Binh
Varocha
V
Mahachai
D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D005500:Follow-Up Studies; D005756:Gastritis / Q000235:genetics / Q000382:microbiology*; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D016481:Helicobacter Infections / Q000235:genetics / Q000382:microbiology*; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics; D006801:Humans; D007812:Laos; D010437:Peptic Ulcer / Q000235:genetics / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D011379:Prognosis; D013274:Stomach Neoplasms / Q000235:genetics / Q000382:microbiology*; D014774:Virulence / Q000235:genetics*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori