title: Helicobacter pylori outer membrane protein Q allele distribution is associated with distinct pathologies in Pakistan.
abstract: Helicobacter pylori (H. pylori) strains expressing outer membrane protein Q (HopQ) promote adherence to the gastric epithelial cell. We characterized HopQ alleles in relation to H. pylori-related disease, histology and virulence markers. Gastric biopsies were obtained at esophagogastroduodenoscopy from patients with upper gastrointestinal symptoms. H. pylori culture, histology and polymerase chain reaction (PCR) for HopQ types, cagA, cagA-promoter and vacA alleles were performed. DNA extracted was used for PCR. Sequencing of PCR products of HopQ types 1 and 2 was followed by BLAST query. We examined 241 H. pylori isolates. HopQ type 1 was positive in 70 (29%) isolates, type 2 in 60 (25%) isolates, while both type 1 and type 2 in 111 (46%) H. pylori isolates, respectively. Nonulcer dyspepsia (NUD) was associated with HopQ type 2 in 48 (41%) isolates, while gastric carcinoma (GC) in 37 (53%) (P<0.001) with type 1 isolates. Gastric ulcers (GU) were 39 (46%) (P<0.001) in H. pylori infection with multiple HopQ alleles compared to 6 (23%) in HopQ type 1. Multivariate analysis demonstrated that multiple HopQ alleles were associated with GU OR 2.9 (1.07-7.8) (P=0.03). HopQ type 1 was associated with cagA 58 (84%) (P<0.001) and cagA-promoter 58 (83%) (P<0.001) compared to 14 (23%) and 17 (28%) respectively, in type 2. VacAs1a was associated with HopQ type 1 in 59 (84%) isolates compared to HopQ type 2 in 35 (58%) (P=0.002) isolates. VacAm1 was associated with HopQ type 1 in 53 (76%) isolates compared to HopQ type 2 in 32 (53%) (P=0.004) isolates. H. pylori infection with multiple HopQ alleles was predominant. H. pylori infection with single HopQ type 1 was associated with GC in the presence of other H. pylori virulence markers.
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan. Electronic address: javed.yakoob@aku.edu.
authors.forename: Javed
authors.initials: J
authors.lastname: Yakoob
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Zaigham
authors.initials: Z
authors.lastname: Abbas
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Rustam
authors.initials: R
authors.lastname: Khan
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Saima Azhar
authors.initials: SA
authors.lastname: Salim
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Safia
authors.initials: S
authors.lastname: Awan
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Ambar
authors.initials: A
authors.lastname: Abrar
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Wasim
authors.initials: W
authors.lastname: Jafri
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D004415:Dyspepsia / Q000175:diagnosis / Q000382:microbiology; D005260:Female; D016481:Helicobacter Infections / Q000382:microbiology* / Q000473:pathology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D017422:Sequence Analysis, DNA / Q000379:methods; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000382:microbiology; D013276:Stomach Ulcer / Q000175:diagnosis / Q000382:microbiology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori
keywords: Gastric carcinoma; Gastric ulcer; Helicobacter pylori; HopQ types 1 and 2; Outer membrane protein Q