An uncultured gastric spiral organism is a newly identified Helicobacter in humans.

"Gastrospirillum hominis" is an uncultivated spiral bacterium in human gastric mucosa that is larger and more tightly coiled than Helicobacter pylori. In an attempt to determine if this organism is a new species of Helicobacter, its 16S rRNA gene was cloned and sequenced. Gastric mucosa from 2 patients infected with "Gastrospirillum hominis" was fed to specific pathogen-free mice. Electron microscopy of gastric tissue confirmed that the mice became colonized with "Gastrospirillum hominis." The 16S rRNA gene from bacterial target sequences was amplified directly from mouse stomach tissue by the polymerase chain reaction (PCR), cloned into Escherichia coli, and sequenced. Both fragments were 16S rRNA genes from the Helicobacter genus that were most closely related to Helicobacter felis. "Gastrospirillum hominis" is probably a newly recognized Helicobacter infection in humans. Because this is the only Helicobacter organism that infects both humans and small animals, it may be particularly suited for studies of pathogenesis.