Abstract
BackgroundTwo-thirds of the world’s population is thought to be infected by Helicobacter pylori. Although most people infected with H. pylori are asymptomatic, this pathogen is associated with several gastric pathologies including cancer. The risk factors for colonization are still unclear and the genetic diversity within individual hosts has never been clearly investigated.ResultThis study determined the prevalence of, and explored risk factors for, H. pylori infection directly from paired saliva (n = 110) and stool (n = 110) samples from asymptomatic persons in Northeast Thailand. Samples were subjected to indirect immunofluorescence assay (IFA), 16S rRNA-based real-time PCR and vacA-based semi-nested PCR. Partial vacA gene sequences of H. pylori were compared between saliva and stool samples.The overall prevalence of H. pylori infection in our asymptomatic study population was 64%. Age, gender, occupation and frequency of brushing teeth were not found to be associated with H. pylori colonization. The vacA gene was successfully sequenced from both saliva and stool samples of 12 individuals. For seven of these individuals, saliva and stool sequences fell into different clusters on a phylogenetic tree, indicating intra-host genetic variation of H. pylori.ConclusionThis study reports a high prevalence of H. pylori infection in asymptomatic persons in this region of Thailand and demonstrates that genotypes (vacA gene sequences) of H. pylori may differ between the oral cavity and intestinal tract.
Highlights
Two-thirds of the world’s population is thought to be infected by Helicobacter pylori
This study reports a high prevalence of H. pylori infection in asymptomatic persons in this region of Thailand and demonstrates that genotypes of H. pylori may differ between the oral cavity and intestinal tract
We investigated the phylogeny of H. pylori based on sequences within the conserved region of the Vacuolating cytotoxin A (vacA) gene from saliva and stool samples
Summary
Two-thirds of the world’s population is thought to be infected by Helicobacter pylori. Most people infected with H. pylori are asymptomatic, this pathogen is associated with several gastric pathologies including cancer. Helicobacter pylori infection is responsible for several gastric diseases, especially major ulcers in the stomach and small intestine. Two-thirds of the world’s population is infected by H. pylori, with the highest prevalences (up to 80%) in developing countries [2]. The isolation of H. pylori is difficult due to the fastidious nature of the organism. This affects estimates of prevalence: different methods and different types of sample can yield different results [10,11,12]. Previous estimates of the prevalence of H. pylori infection in stool samples of asymptomatic
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