Evidence for an oral-faecal transmission of Helicobacter pylori infection in an experimental murine model

An experimental murine model was used to evaluate the possible animal-to-an imal transmission of Helicobacter pylori and the mechanism involved. Twenty -four Balb/C mice were infected with H. pylori type I strain culture and ke pt with 24 noninoculated mice to evaluate the possible transmission of the microorganism. Twelve inoculated mice were housed with 12 noninoculated mic e in a grated cage (supporting an oral-oral transmission); the remaining in oculated and noninoculated mice were housed in another cage without grating on the floor (supporting a faecal-oral transmission). The bacterial coloni zation was assessed by culture and immunohistochemistry. The systemic antib ody response to H. pylori and the histopathological changes were evaluated; controls were examined at 2, 4, 8, 12 weeks after the start of the experim ent. Faecal samples tvere also collected from each mouse on the day before sacrifice, to assess the presence of H. pylori by culture and by immunohist ochemistry. In the gastric mucosa of inoculated mice, histopathological cha nges were recorded at each control time and H, pylori was detected both by immunohistochemistry and by a systemic antibody response; the microorganism was also cultured at 2, 4, 8 weeks postinoculation. H, pylori was detected in noninoculated mice, housed in the cage without grating, using an immuno peroxidase technique at 2, 4, 8 weeks after starting the experiment, and th ese positive values were supported by histopathological changes, and, in on e case, at 8 weeks, also by the serum immune response. No colonies of H. py lori were detected by culturing faecal samples from either noninoculated or inoculated mice. The results obtained in this study seem to support an ora l-faecal route as the mode of transmission of H. pylori infection in this a nimal model.