Analysis of virulence factors of Helicobacter pylori isolated from a Vietnamese population.
BACKGROUND
The incidence of gastric cancer differs among countries in Asia, and it has been suggested that virulence factors associated with Helicobacter pylori are partly responsible. The aim of this study was to investigate several genetic factors regarded as virulence or molecular epidemiologic markers in H. pylori isolates from Vietnamese subjects.


RESULTS
The cagA, vacA and cag right-end junction genotypes of 103 H. pylori strains from Vietnam (54 from Hanoi and 49 from Ho Chi Minh) were determined by PCR and sequencing. Three types of deletion in the region located upstream of the cagA Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region were identified: the 39-bp deletion type, the 18-bp deletion type, and the no-deletion type. The majority of strains studied (77%; 80/103) had the 18-bp deletion irrespective of geographical location in the country or clinical outcome. All of the 39-bp and 18-bp deletion-type strains possessed the East Asian type cagA repeat region. The type II cag right-end junction genotype was predominant (84%). The vacA m1 genotype was significantly more common in strains isolated in Hanoi, where the incidence of gastric cancer is higher, than in strains from Ho Chi Minh.


CONCLUSIONS
Pre-EPIYA-region typing of the cagA gene could provide a new genetic marker of H. pylori genomic diversity. Our data support the hypothesis that vacA m1 is closely associated with gastric carcinogenesis.
Uchida
Tomohisa
T
Department of Molecular Pathology, Oita University Faculty of Medicine, Yufu, Japan. tomohisa@med.oita-u.ac.jp
Nguyen
Lam Tung
LT
Takayama
Akiko
A
Okimoto
Tadayoshi
T
Kodama
Masaaki
M
Murakami
Kazunari
K
Matsuhisa
Takeshi
T
Trinh
Tuan Dung
TD
Ta
Long
L
Ho
Dang Quy Dung
DQ
Hoang
Hoa Hai
HH
Kishida
Tetsuko
T
Fujioka
Toshio
T
Moriyama
Masatsugu
M
Yamaoka
Yoshio
Y
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D014744:Vietnam; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori
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