Molecular epidemiology of Helicobacter pylori in England: prevalence of cag pathogenicity island markers and IS605 presence in relation to patient age and severity of gastric disease

• Published in: FEMS immunology and medical microbiology Vol. 30; no. 1; pp. 65 - 71
• Main Authors: Owen, Robert J, Peters, Tansy M, Varea, Ruben, Teare, E. Louise, Saverymuttu, Seth
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2001; Blackwell; Oxford University Press
• Subjects: Adolescent; Adult; Age; Age composition; Age Distribution; Aged; Aged, 80 and over; Antigens, Bacterial; Bacterial Proteins - genetics; Bacteriology; Biological and medical sciences; cag pathogenicity island; cagA; cagA gene; CagA protein; DNA Transposable Elements - genetics; Dyspepsia; Dyspepsia - microbiology; England - epidemiology; Epidemiology; Esophagitis; Female; Fundamental and applied biological sciences. Psychology; Gastric cancer; Gastritis; Gastritis - microbiology; Genes; Genomes; Genotypes; Helicobacter Infections - epidemiology; Helicobacter Infections - microbiology; Helicobacter pylori; Helicobacter pylori - genetics; Helicobacter pylori - pathogenicity; Humans; Insertion; insertion sequence IS605; Inserts; IS605 element; Male; Markers; Microbiology; Middle Aged; Molecular Epidemiology; Mucosa; Pathogenicity; pathogenicity islands; Pathogens; peptic ulcer; Peptic Ulcer - epidemiology; Peptic Ulcer - microbiology; Peptic ulcer disease; Population studies; Prevalence; Severity of Illness Index; Strains (organisms); Trinucleotide repeats; Ulcers; Virulence; England; United Kingdom; Great Britain; Europe; United Kingdom > UK; pathogenicity island; IS; Peptic ulcer disease; Epidemiology; Age; element; Human; Stomach; Prevalence; Genetic variability; Spirillales; Spirillaceae; Transposable element; Malignant tumor; Pathogenicity island; IS element; Pathogenicity; Helicobacter pylori; Molecular epidemiology; Digestive diseases; Bacteria; Anastomotic ulcer; Gastric disease
• ISSN: 0928-8244; 1574-695X; 2049-632X
• DOI: 10.1111/j.1574-695X.2001.tb01551.x

Abstract The cagA gene is a key marker for the Helicobacter pylori cag pathogenicity island (PAI), which may vary in composition in different strains with insertion sequence mediated interruptions and deletions of genes. While presence of cagA has been associated with increased risk for peptic ulcer disease and gastric cancer, the precise link with virulence is controversial. We investigated H. pylori from dyspeptics in one location in England (mid-Essex) with reference to the prevalence and distribution by age cohort of different cag PAI forms to determine if presence of the insertion element IS605 had a modifying effect on the severity of associated disease. H. pylori isolated from gastric biopsies over a 4-year period were screened by specific PCR assays for the presence of cagA, cagD, cagE and virD4 genes in the cag PAI, and for the presence of IS605 in the PAI and elsewhere in the genome. Most (68%) of the 166 isolates of H. pylori contained a PAI based on detection of cagA whereas 29% had no detectable PAI using multiple loci. The cagA+ genotype frequencies were similar in the peptic ulcer and non-ulcer dyspepsia—gastritis groups (79% vs. 74%) whereas frequencies in the NUD—oesophagitis and normal mucosa groups were lower (58%) but not significantly different (P>0.41). Genomic IS605 inserts were present at an overall frequency of 32% and were widely distributed with respect to patient age and disease severity. The combined cagA+/IS- strain genotype was common but not significantly associated with PUD compared to endoscopically normal mucosa (P=0.807). We concluded that presence of the IS605 element, whether in cagA+ or cagA- strains of H. pylori, did not systematically modify the severity of associated disease in the study population.