ADAPTATION OF THE [C-13]UREA BREATH TEST AS A NONINVASIVE METHOD FOR DETECTION OF HELICOBACTER-PYLORI INFECTION IN SQUIRREL-MONKEYS (SAIMIRI SPP)

The [C-13]urea breath test was adapted for use in squirrel monkeys (Sa imiri spp.) for identification of experimentally induced infection wit h Helicobacter pylori, the bacterium causing gastric ulcer in humans. A canine anesthesia inhalation mask was modified with a volume-reducin g insert allowing sufficient breath collection from these small primat es within 30 sec. Fourteen milligrams of [C-13]urea per kilogram of bo dy weight was adequate for clear distinction between experimentally in fected and noninfected animals. Initial infection of five squirrel mon keys resulted in increased (CO2)-C-13 in breath within 3 days after in oculation with H. pylori. Additional inoculation with H. pylori superi mposed on an existing gastric population caused a transient increase i n breath (CO2)-C-13 values, which gradually declined over the followin g 15 days. Breath test results indicating H. pylori infection were con firmed by high [C-13] concentration in blood, by urease-positive cultu re, modified Steiner stain reaction, and Western blot analysis. This m odified [C-13]urea breath test provides a rapid, reproducible, noninva sive method for screening small primates used as nonhuman models for t he study of gastric infection with H. pylori.