QUANTITATIVE DETECTION OF H. PYLORI IN BIOLOGICAL SAMPLES

摘要

A subclinical epizootic of chronic active gastritis, gastric erosions and presence of H. pylori-like bacteria was previously observed in a Cynomolgus monkey colony. The present study was to determine whether the bacteria were H. pylori, to characterize the strains, and to evaluate whether the presence of virulence genes was correlated with clinical pathology. Gastric specimens from a subgroup of 12 animals found positive by histology were cultured, and Random Amplification of Polymorphic DNA (RAPD) technique was used to fingerprint 19 strains isolated from five of these animals. Strains isolated from monkeys bred in Vietnam had an identical pattern, which was different from that of strains isolated from a monkey bred in the Philippines. All isolates were of the s1 a vacA subtype, but "Vietnamese" isolates were cagA+ and iceA1+, whereas "Philippino" isolates were cagA- and iceA2+. The 16S rRNA gene of one "Vietnamese" and one "Philippino" isolate was sequenced and compared with H. pylori sequences reported in GenBank. Sequences were 98.6 to 99.6 homologous with the 16S rRNA of ten H. pylori isolates, whereas the homology of H. acynonix was 94.7% and that of other Helicobacter species was <90%. In addition, strains isolated from these animals varied according to the country of origin, thus indicating probable infection prior to importation. These observations demonstrate that the epizootic of gastritis observed in Cynomolgus monkeys was caused by H. pylori, and that the Cynomolgus monkey may be a useful model to investigate the role of H. pylori in ulcerogenesis.