title: Surveillance and clinical relevance of vacA genotypes of Helicobacter pylori infecting dyspeptic patients in mid-Essex.
abstract: The Helicobacter pylori vacuolating cytotoxin is a putative pathogenicity factor encoded by vacA, a mosaic gene with a global distribution. The vacA type prevalence and diversity of H. pylori isolated from antral gastric biopsies of 360 dyspeptic patients in mid-Essex, and of 79 patients from other locations, were investigated in order to test for links with disease severity. Mid (m)-region genotyping and subtyping by vacA HaeIII RFLP (restriction fragment length polymorphism) analysis showed that the m1 and m2 alleles were diverse, with 191 different subtypes. Variation in 44% of strains was accounted for by ten subtypes of which subtype v-1 represented a conserved core (33%) of the m1 form. Prevalence rates for combined mid and signal (s)-region genotypes were 40% for s1/m1, 46% for s1/m2, and 11% for s2/m2. Overall, vacA genotyping provided high typability and discrimination, but no specific RFLP markers could reliably predict a clinically significant presentation due to an H. pylori infection.
authors.affiliation: PHLS Helicobacter Reference Unit, Laboratory of Enteric Pathogens, Central Public Health Laboratory, 61 Colindale Avenue, London NW9 5HT. rowen@phls.nhs.uk
authors.forename: R J
authors.initials: RJ
authors.lastname: Owen
authors.forename: J
authors.initials: J
authors.lastname: Xerry
authors.forename: T M
authors.initials: TM
authors.lastname: Peters
authors.forename: E L
authors.initials: EL
authors.lastname: Teare
mesh_terms: D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D004415:Dyspepsia / Q000453:epidemiology / Q000382:microbiology*; D004739:England / Q000453:epidemiology; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D017720:Molecular Epidemiology; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D017931:DNA Primers; C074689:VacA protein, Helicobacter pylori