title: Association of Malaysian Helicobacter pylori virulence polymorphisms with severity of gastritis and patients' ethnicity.
abstract: OBJECTIVE
  Polymorphisms of Helicobacter pylori cagA and vacA genes do exist and may contribute to differences in H. pylori infection and gastroduodenal diseases among races in the Malaysian population. This study was conducted to characterize the polymorphisms in H. pylori cagA and vacA in Malaysian population.
  
  
  METHODS
  A total of 110 H. pylori isolates were genotyped by PCR and sequenced for cagA and PCR-RFLP for vacA.
  
  
  RESULTS
  East Asian cagA was predominantly detected (64.5%), whereas vacA s1m1 and s1m2 alleles were detected in 60.9 and 37.3% of strains, respectively. A statistical association between cagA type with patients' ethnicity (p < .0001) and age group >50 years old (p = .027) was identified. vacA alleles showed significant association with age group >50 years old (p = .017) and increased neutrophil activity in gastric mucosa (p = .028 and p = .016 for moderate and marked activity, respectively). Further identification of vacA polymorphism revealed that 84% of strains from Malays and Indians showed one RFLP pattern (RFLP-1), whereas more than one RFLP patterns (RFLP-2, 3, 4, 5, 6, and 8) were predominantly observed in strains from Chinese (82%) (p < .0001). Increasing severity of gastric inflammation was observed in gastric mucosa infected with strains carrying RFLP-2, 3, 4, 5, and 6 (p = .037). About 86.6% of H. pylori strains with East Asian cagA were vacA RFLP-2, 3, 4, 5, 6, and 8, and 88% of Western cagA strains were vacA RFLP-1 (p < .0001). Chinese and Indians are susceptible to different virulence genotypes of H. pylori, whereas Malays showed a mixed virulence genotypes.
  
  
  CONCLUSIONS
  Marked differences in the polymorphisms of cagA and vacA were observed among strains in Malaysian population. This provides a new insight into the pathogenicity of H. pylori in multiracial population.
authors.affiliation: Department of Medical Microbiology & Immunology, National University of Malaysia, Cheras, Kuala Lumpur, Malaysia. alfizah@ppukm.ukm.my
authors.forename: Hanafiah
authors.initials: H
authors.lastname: Alfizah
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ramelah
authors.forename: Abdul M
authors.initials: AM
authors.lastname: Rizal
authors.forename: Abdullah S
authors.initials: AS
authors.lastname: Anwar
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Isa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005006:Ethnicity; D005260:Female; D005756:Gastritis / Q000382:microbiology / Q000473:pathology; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology* / Q000473:pathology*; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008296:Malaysia; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori