Ultrastructure of a spiral micro-organism from pig gastric mucosa ("Gastrospirillum suis")

Laboratory of Research in Bacteriology * Electron Microscopic Centre ‘Faculdade de Medicina’ UFMG, Av.Alfredo Balena, 190-CEP 30130, Belo Horizonte, MG, Electron Microscopic Unit ‘Instituto de Microbiologia’ UFRJ, Rio de Janeiro, RJ, Brasil Received January 5, 1990 Accepted March 19, 1990 The ultrastructural features of a helical-shaped bacterium occurring inthe stomach of pigs, within the mucus on the mucosal surface of antral pits,were examined. The bacterial cell had three to eight spiral turns, flattened and truncated ends and was approximately 4°0 µm long and 0°6 µm wide.In some sections, up to six flagella, about 22 nm in diameter, were seen arising from each pole. The cytoplasm contained sparse, irregular granules,numerous ribosomes and large single-layered membrane-bound granules. In the flagella insertion area, there was a highly electron-dense component,the "polar membrane". This micro-organism differed from similar bacteria described in cats, dogs and monkeys, and may cause inflammation in the antral mucosa of pigs similar to Helicobacter pylori infection in man. Furthermore, it was morphologically similar to the spiral micro-organism distinct from H. pylori which has been described recently in human antral mucosa from patients with gastritis and may be of potential significanceas a pathogen in man. The name "Gastrospirillum suis" is proposedfor this bacterium.