A spiral bacterium (SH9), morphologically different from Helicobacter pylori (H. pylori), was found in a 62-year-old woman's gastric mucosa. Gastroscopic examination revealed multiple gastric ulcers near the pyloric ring; mapping gastric biopsy showed mild mononuclear infiltration with large lymphoid follicles in the antrum, without corpus atrophy. Urea breath test and H. pylori culture were negative, but Giemsa staining of biopsies revealed tightly coiled bacteria that immunostained with anti-H. pylori antibody. Sequencing of SH9 16S rRNA and the partial urease A and B subunit genes showed that the former sequence had highest similarity (99%; 1302/1315 bp) to Helicobacter heilmannii (H. heilmannii) sensu stricto (H. heilmannii s.s.) BC1 obtained from a bobcat, while the latter sequence confirmed highest similarity (98.3%; 1467/1493 bp) to H. heilmannii s.s. HU2 obtained from a human. The patient was diagnosed with multiple gastric ulcers associated with H. heilmannii s.s. infection. After triple therapy (amoxicillin, clarithromycin, and lansoprazole) with regimen for eradicating H. pylori, gastroscopy showed ulcer improvement and no H. heilmannii s.s. upon biopsy.
Keywords: Gastric ulcers; Helicobacter heilmannii sensu stricto; Non-Helicobacter pylori helicobacters; Urease gene; “Helicobacter heilmannii” type 2.