Intact long-type dupA as a marker for gastroduodenal diseases in Okinawan subpopulation, Japan.
BACKGROUND
Helicobacter pylori dupA can be divided into two types according to the presence or absence of the mutation. In addition, full-sequenced data revealed that dupA has two types with different lengths depend on the presence of approximately 600 bp in the putative 5' region (presence; long-type and absence; short-type), which has not been taken into account in previous studies.


METHODS
A total of 319 strains isolated from Okinawa, the south islands of Japan, were included. The status of dupA and cagA was determined by polymerase chain reaction. The presence of mutations in long-type dupA was determined by DNA sequencing.


RESULTS
The prevalence of long-type dupA was 26.3% (84/319). Sequence analysis showed that there were only six cases (7.1%) with point mutations lead to stop codon among 84 long-type dupA strains studied. Interestingly, intact long-type dupA without frameshift mutation, but not short-type dupA, was significantly associated with gastric ulcer and gastric cancer than gastritis (p = .001 and p = .019, respectively). After adjustment by age, gender, and cagA, the presence of intact long-type dupA was significantly associated with gastric ulcer and gastric cancer compared with gastritis (odds ratio [OR] = 3.35, 95% confidence interval [CI] = 1.55-7.24 and OR = 4.14, 95% CI = 1.23-13.94, respectively).


CONCLUSIONS
Intact long-type dupA is a real virulence marker for severe outcomes in Okinawa, Japan. The previous information gained from PCR-based methods without taking long-type dupA into account must be interpreted with caution.
Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, 879-5569, Japan.
Ayaka
A
Takahashi
Seiji
S
Shiota
Osamu
O
Matsunari
Masahide
M
Watada
Rumiko
R
Suzuki
Saori
S
Nakachi
Nagisa
N
Kinjo
Fukunori
F
Kinjo
Yoshio
Y
Yamaoka
D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D005756:Gastritis / Q000453:epidemiology* / Q000382:microbiology; D005819:Genetic Markers; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000382:microbiology; D013276:Stomach Ulcer / Q000453:epidemiology* / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C528428:DupA protein, Helicobacter pylori; D005819:Genetic Markers; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori