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. 2018 Jan 30;18(1):10.
doi: 10.1186/s12866-018-1150-7.

Detection and genotyping of Helicobacter pylori in saliva versus stool samples from asymptomatic individuals in Northeastern Thailand reveals intra-host tissue-specific H. pylori subtypes

Phattharaphon Wongphutorn  1   2 , Chariya Chomvarin  3   4 , Banchob Sripa  5 , Wises Namwat  1   6 , Kiatichai Faksri  7   8
Affiliations

Detection and genotyping of Helicobacter pylori in saliva versus stool samples from asymptomatic individuals in Northeastern Thailand reveals intra-host tissue-specific H. pylori subtypes

Phattharaphon Wongphutorn et al. BMC Microbiol. .

Abstract

Background: Two-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.

Result: This 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.

Conclusion: This 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.

Keywords: Genetic diversity; Genotyping; Helicobacter pylori; Saliva; Stool; vacA.

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Conflict of interest statement

Ethics approval and consent to participate

Written ethical consents were received from participants. The study was approved by Institutional Human Ethics Committee of Khon Kaen University (HE571489).

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Study population and classification criteria of the tested samples
Fig. 2
Fig. 2
Detection of H. pylori directly from stool samples using IFA, semi-nested PCR targeting vacA and real-time PCR targeting 16S rRNA. (A) Fluorescent photomicrograph of H. pylori in various concentrations (CFUs/0.1 g), NC and PC refers to negative (sterile Brucella broth) and positive control (H. pylori DMST 20165 in Brucella broth), respectively. (B) Semi-nested PCR targeting vacA in spiked stool samples. Lane M, 1 kb DNA ladder; Lane 1, negative control (PCR reagent without DNA); Lane 2, positive control (DNA sample from H. pylori DMST20165); Lanes 3–11, stool samples spiked with various numbers of H. pylori cells (108–100 CFUs/0.1 g). (C) Amplification curve of SYBR green real-time PCR targeting 16S rRNA in spiked stool samples. Black line, positive control (DNA sample from H. pylori DMST20165); Red line, 106; orange line, 104; blue line, 103; purple line, 101 CFUs/0.1 g; grey line, Non-template control (PCR reagent without DNA)
Fig. 3
Fig. 3
Maximum Likelihood tree of 276-bp vacA gene H. pylori isolated from saliva and stool samples of asymptomatic individuals from Northeastern Thailand. An asterisk indicates the 12 subjects from which the vacA gene in both saliva and stool samples were sequenced. In seven out of 12 pairs (Healthy 3, 151,153, 154, 158, 159 and 164), sequences of H. pylori detected from saliva samples were in a separate cluster to those from stool samples
See this image and copyright information in PMC

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