A gastric mucosa in vitro model for studies of experimental Helicobacter pylori infections has been developed. Biopsy specimens were taken from pig gastric mucosa, infected with H. pylori, and cultured for up to 72 h. To determine the degree of H. pylori adhesion, specimens were vigorously rinsed by vortexing five times before measuring viable count and urease activity. The results showed that it is possible to culture pig gastric mucosa in vitro with maintained viability for at least 72 h. According to the viable count, the bacteria survived and multiplied during the whole culture period. The percentage viable H. pylori in the specimens after rinsing and the urease activity increased with time of culture. The results indicate that the bacteria in the gastric specimens were viable after 72 h and that there was a time-dependent increase in bacterial adhesion to the specimens. This in vitro gastric mucosa model promises to be an applicable and reproducible method, with high capacity, for both pathogenic and mechanistic studies of H. pylori infection.

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Four barrier-born pigs were inoculated with Helicobacterpylori during gastroscopy. Infection in all pigs was established after 3 weeks, and the animals were kept isolated from other pigs in ordinary experimental sties. The pigs were sacrificed and examined 3, 5, 6, and 6.5 months postinoculation. A detailed urease mapping of the pig stomachs showed a patchy distribution of H. pylon. The bacteria colonized in all pigs, with a concentration of H. pylon-positive areas in the antrum and fundus. Furthermore, the number of colonized areas tended to increase with time, and some of these areas showed a strong urease reaction, indicating a heavy colonization with H. pyloni. Biopsies from these areas contained 102 to 105 CFU per 2-mm-wide biopsy. We conclude that persistence ofH. pylon infection in barrier-born pigs can be demonstrated for at least 6.5 months.