Diversity of Helicobacter pylori cagA and vacA genes in Costa Rica: its relationship with atrophic gastritis and gastric cancer.
BACKGROUND
Associations between Helicobacter pylori gene diversity and gastric cancer have not been reported on in Costa Rica, despite its being one of the countries with the highest gastric cancer incidence and mortality rates in the world. The aim of this study was to determine the prevalence of H. pylori cagA and vacA genes and investigate whether it could be correlated with atrophic gastritis (AG) and gastric cancer (GC) in Costa Rica.


METHODS
Genomic DNAs from isolates of 104 patients classified into two groups: non-atrophic gastritis group (n = 68) and atrophic gastritis group (n = 36), were subjected to PCR-based genotyping of cagA and vacA genes and their correlation with clinical outcome was investigated. Total DNA extractions from gastric tissues of 25 H. pylori-infected gastric cancer patients were utilized for comparative purposes.


RESULTS
The presence of cagA (75.3%), vacA s1b (75.3%), and vacA m1 (74.2%) was detected, and colonization by strains with different vacA genotypes in the same stomach was found in 9.7% of the patients. Age- and sex-adjusted vacA s1b and vacA m1 were associated with GC while only vacA m1 was significantly associated with AG. A tendency for association between cagA and vacA s1b, and AG was reported.


CONCLUSIONS
The prevalence status of the cagA and vacA (s1/m1) genes in Costa Rica seems to fall between that found in European/North American and East Asian countries, and both cagA and vacA seem to have clinical relevance in this country.
Con
Sergio A
SA
Department of Clinical Laboratory Medicine, Kochi Medical School, Kochi University, Nankoku City, Kochi 783-8505, Japan.
Takeuchi
Hiroaki
H
Valerín
Ana L
AL
Con-Wong
Reinaldo
R
Con-Chin
Gil R
GR
Con-Chin
Vicky G
VG
Nishioka
Mitsuaki
M
Mena
Fernando
F
Brenes
Fernando
F
Yasuda
Nobufumi
N
Araki
Keijiro
K
Sugiura
Tetsuro
T
D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D003364:Costa Rica / Q000453:epidemiology; D005260:Female; D005757:Gastritis, Atrophic / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology*; D014644:Genetic Variation; D016481:Helicobacter Infections / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori