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.
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. pylori16S 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.
Authors: Nuri Kodaman; Alvaro Pazos; Barbara G Schneider; M Blanca Piazuelo; Robertino Mera; Rafal S Sobota; Liviu A Sicinschi; Carrie L Shaffer; Judith Romero-Gallo; Thibaut de Sablet; Reed H Harder; Luis E Bravo; Richard M Peek; Keith T Wilson; Timothy L Cover; Scott M Williams; Pelayo Correa Journal: Proc Natl Acad Sci U S A Date: 2014-01-13 Impact factor: 11.205
Authors: Débora Menezes da Costa; Eliane dos Santos Pereira; Silvia Helena Barem Rabenhorst Journal: World J Gastroenterol Date: 2015-10-07 Impact factor: 5.742
Authors: Sarah Talarico; Mahboobeh Safaeian; Paula Gonzalez; Allan Hildesheim; Rolando Herrero; Carolina Porras; Bernal Cortes; Ann Larson; Ferric C Fang; Nina R Salama Journal: Helicobacter Date: 2015-12-15 Impact factor: 5.753
Authors: Lucia Libanez Bessa Campelo Braga; Maria Aparecida Alves de Oliveira; Maria Helane Rocha Batista Gonçalves; Fernando Kennedy Chaves; Tiago Gomes da Silva Benigno; Adriana Dias Gomes; Cícero Igor Simões Moura Silva; Charles Anacleto; Sérgio de Assis Batista; Dulciene Maria Magalhães Queiroz Journal: Mem Inst Oswaldo Cruz Date: 2014-12-09 Impact factor: 2.743
Authors: Mohammad Yousef Alikhani; Mohammad Reza Arebestani; Masood Sayedin Khorasani; Amir Majlesi; Mohammad Jaefari Journal: Iran Red Crescent Med J Date: 2014-11-05 Impact factor: 0.611