Porcine stomachs with and without gastric ulcer differ in Lactobacillus load and strain characteristics

Although Lactobacillus species are recognized as normal inhabitants of porcine gastric mucosa, the association of these bacteria with health status or gastric ulcer disease has never been considered. We investigated the bacterial load of Lactobacillus isolated from the antrum, corpus, and pars esophagea of stomachs with (n = 13) and without (n = 10) ulcer of the pars esophagea of slaughtered pigs. We also evaluated in vitro antagonistic properties against typical pathogens of strains isolated from stomachs without ulcer. To quantify Lactobacillus, gastric mucosa samples obtained with 5 mm biopsy punches were smeared on MRS agar and colonies were counted after 48 h of incubation under anaerobic conditions. The score of Lactobacillus was significantly greater in the antrum and corpus of stomachs without ulcer (P < 0.001 for both) when compared with stomachs with ulcer. Fingerprint profiles, obtained by repetitive sequence-based PCR using (GTG)₅ primers, showed that the isolates were highly diverse. The reduction of Lactobacillus load in porcine stomachs may be a contributing factor for gastric ulcer. Strains isolated from healthy stomachs, which showed a wide spectrum of antagonistic activity against pathogens, may be viewed as an untapped source of bacteria with potential beneficial properties that deserve to be further investigated.