In situ mapping of urease-positive areas in porcine gastric mucosa.

Urease activity is a feature of gastric helicobacters, and its abundant production provides an indirect means of detecting their colonization. A method for mapping urease-positive areas directly on the gastric mucosa was developed, and 57.8% of pigs had evidence of Helicobacter colonization based on urease assay. Moreover, 89.2% of urease-positive pigs had gastritis, confirming that the known association found in man between Helicobacter and gastritis was found also in pigs. The proposed urease assay allowed detection of all urease-positive areas on the gastric mucosa, thus overcoming the biopsy sampling problems derived from the patchy distribution of helicobacters. In this way, gastric mucosa specimens from urease-positive areas could be usefully utilized for culture attempts and for microscopic examination.