Mohammadi, MahnazAbadi, Amin Talebi BezminRahimi, FaridForootan, Mojgan2020-07-200188-4409http://hdl.handle.net/1885/206377Introduction. We aimed to study potential associations between colonization by four common non-pylori Helicobacter species and gastroduodenal diseases by comparing samples from patients infected with H. pylori with samples from non-infected subjects. Materials and Methods. Patients (n 5 190) who were subjected to upper gastrointestinal endoscopy because of gastroduodenal conditions were enrolled in this cross-sectional study. Antral biopsy samples were taken from patients in two major hospitals (Mehrad and Imam-Hossein) in Tehran, Iran, during 2017e2018. DNA was isolated from the biopsy specimens, and PCR amplification was used to identify the Helicobacter species by using their corresponding specific primer sets. Results. Out of 120 cases positive for H. pylori, 46 (38%) were patients with gastritis, 23 (19%) with duodenal ulcer, 11 (9%) with gastric cancer, and 40 (33.3%) with gastric ulcer. Overall, 70 (36%) patients were negative for H. pylori. H. pylori cases were uninfected by any of the other tested Helicobacter species. Among the 70 patients without H. pylori, 34 had gastritis—31 (94%) of these were positive also for H. heilmannii ( p 5 0.001, Odds Ratio: 51.6; 95% Confidence Intervals: 11.8e225.6). We did not find any patient carrying mixed Helicobacter infections with any non-pylori Helicobacter species in this cohort. Conclusions. Given our evidence about the possibility of involvement of H. heilmannii in patients suffering from gastritis and nonexistence of mixed non-pylori Helicobacter infections, bacteriological testing of subjects negative for H. pylori becomes clinically relevant and important.The present study was financially supported by the grant 94014027 by the Iran National Science Foundation (INSF).application/pdfen-AU© 2019 IMSS201910.1016/j.arcmed.2019.11.0012020-04-12