title: A better method for confirming Helicobacter pylori infection in Mongolian gerbils.
abstract: BACKGROUND
  Our aim was to evaluate the accuracy of the stool antigen test and the optimal time point for detecting Helicobacter pylori infection in a Mongolian gerbil model.
  
  
  METHODS
  We inoculated 8-week-old Mongolian gerbils with H. pylori (Vac A (+)/CagA(+)). The gerbil-infected model was developed as follows: H. pylori was put into broth (about 10(9) CFU/ml), and 50 gerbils were then fed with 1 ml intragastrically twice within a 3-day interval. Another ten gerbils were fed broth only. Twenty-six weeks after the inoculation, the gerbils were killed. The gastric mucosa was sampled for a series of examinations including culture, histology, rapid urease test, and polymerase chain reaction. Stool samples for a stool antigen test, H. pylori-specific stool antigen assay (HpSA), were collected during weeks 4, 6, 8, 12, and 26 after inoculation. Of the 50 gerbils inoculated with H. pylori, the inoculation was successful in 88%. Severe active gastritis, ulceration, and intestinal metaplasia were obvious.
  
  
  RESULTS
  The HpSA test results were sensitivity, 88.6%; specificity, 100%; positive predictive value (PPV), 100%; negative predictive value (NPV), 54.5%, and accuracy, 90%. The HpSA test began to be more sensitive and accurate (P < 0.05) beginning during week 6 after inoculation. We also found that H. pylori could be detected earlier and more easily in the group with high H. pylori density.
  
  
  CONCLUSIONS
  HpSA seems to be suitable for confirming colonization of gerbils with H. pylori. The optimal testing time point is around 6 weeks after inoculation. This test is a good choice for long-term observation of H. pylori infection in Mongolian gerbils.
authors.affiliation: Division of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan.
authors.forename: Chao-Hung
authors.initials: CH
authors.lastname: Kuo
authors.forename: Huang-Ming
authors.initials: HM
authors.lastname: Hu
authors.forename: Pei-Yun
authors.initials: PY
authors.lastname: Tsai
authors.forename: Sheau-Fang
authors.initials: SF
authors.lastname: Yang
authors.forename: Lin-Li
authors.initials: LL
authors.lastname: Chang
authors.forename: Jaw-Yuan
authors.initials: JY
authors.lastname: Wang
authors.forename: Angela
authors.initials: A
authors.lastname: Chen
authors.forename: Chang-Ming
authors.initials: CM
authors.lastname: Jan
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Wang
authors.forename: Deng-Chyang
authors.initials: DC
authors.lastname: Wu
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D001706:Biopsy; D004269:DNA, Bacterial / Q000235:genetics*; D003937:Diagnosis, Differential; D004195:Disease Models, Animal; D005243:Feces / Q000382:microbiology; D005753:Gastric Mucosa / Q000382:microbiology* / Q000473:pathology; D005756:Gastritis / Q000175:diagnosis / Q000382:microbiology*; D005849:Gerbillinae; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D051381:Rats; D012720:Severity of Illness Index
chemical_list: D000942:Antigens, Bacterial; D004269:DNA, Bacterial