AN UNCULTURED GASTRIC SPIRAL ORGANISM IS A NEWLY IDENTIFIED HELICOBACTER IN HUMANS

''Gastrospirillum hominis'' is an uncultivated spiral bacterium in hum an gastric mucosa that is larger and more tightly coiled than Helicoba cter pylori. In an attempt to determine if this organism is a new spec ies of Helicobacter, its 16S rRNA gene was cloned and sequenced. Gastr ic mucosa from 2 patients infected with ''Gastrospirillum hominis'' wa s fed to specific pathogen-free mice. Electron microscopy of gastric t issue confirmed that the mice became colonized with ''Gastrospirillum hominis.'' The 16S rRNA gene from bacterial target sequences was ampli fied directly from mouse stomach tissue by the polymerase chain reacti on (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 probabl y a newly recognized Helicobacter infection in humans. Because this is the only Helicobacter organism that infects both humans and small ani mals, it may be particularly suited for studies of pathogenesis.