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Non‐invasive Genotyping of Helicobacter pylori cagA, vacA, and hopQ from Asymptomatic Children
Author(s) -
Sicinschi Liviu A.,
Correa Pelayo,
Bravo Luis E.,
Peek Richard M.,
Wilson Keith T.,
Loh John T.,
Yepez Maria C.,
Gold Benjamin D.,
Thompson Dexter T.,
Cover Timothy L.,
Schneider Barbara G.
Publication year - 2012
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/j.1523-5378.2011.00919.x
Subject(s) - caga , helicobacter pylori , genotyping , genotype , virulence , asymptomatic , allele , biology , polymerase chain reaction , microbiology and biotechnology , gene , medicine , genetics
Background: Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non‐invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy. Methods: H. pylori status of 86 asymptomatic children was assessed by 13 C‐urea breath test (UBT) and PCR. H. pylori 16S rRNA , cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced. Results: UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA ‐positive children. Of the children’s DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ . Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes ( p < 0.0001). Conclusions: Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.