To gain a better understanding of transmission and selecting appropriate measures for preventing the spread of Helicobacter pylori, the aim of this study was to investigate the prevalence of H. pylori in drinking water samples in Kermanshah, Iran. Drinking water samples were collected from around Kermanshah and filtered through 0.45 μm nitrocellulose filters. The bacterial sediment was subjected to DNA extraction and polymerase chain reaction (PCR) for H. pylori detection using newly designed primers targeted at the conserved region of the ureC gene. The overall detection rates for H. pylori DNA in the water samples were 56% (66/118) with a frequency of 36% (25/70) in tap water samples and 85% (41/48) in wells. The detection limit was 50 bacteria per liter of filtered water and a pure H. pylori DNA copy number of 6 per reaction. Based on the evidence we may suggest that recontamination occurred and H. pylori entered into the water piping system through cracked or broken pipes or was released from established H. pylori biofilms on pipes. In conclusion, a high prevalence of H. pylori was detected in drinking water samples that strengthens the evidence of H. pylori transmission through drinking water.

Background: There should be a public environmental reservoir for Helicobacter pylori in the developing countries, such as Iran, due to their high infection rate of over 70%. Epidemiological findings revealed that water could be a possible source of H. pylori transmission. However, high prevalence of H. pylori in drinking water in Kermanshah, West of Iran, was detected in the authors' previously published study. The current study aims at designing a more accurate and rapid procedure to investigate the prevalence of Helicobacter species and cagA gene in drinking water samples in Kermanshah, from October to December 2012. Methods: In the current study, 60 tap water samples were obtained and specific polymerase chain reaction (PCR) targeted cagA and 16s rRNA was performed. A loop-mediated isothermal amplification (LAMP) targeted ureC gene was developed to accurately detect H. pylori in water samples. Results: The prevalence of ureC by PCR, ureC by LAMP and 16s rRNA by PCR were 26.67%, 38%, and 61.67%, respectively. Among 24 samples (40%), 1 of the 2 tests was positive. The prevalence of cagA gene among ureC positive, 16s rRNA positive and all samples were 18.75%, 13.51%, and 10%, respectively. Conclusions: Helicobacter pylori contamination in drinking water was considerably higher using LAMP compared with PCR. It is noteworthy that some H. pylori positive samples were also positive for Caga.