Evaluating the validity of the serologic test for detecting Helicobacter pylori infection in Mongolian gerbils.

A strong correlation between Helicobacter pylori infection and gastric cancer has been reported. Mongolian gerbils are regarded as the most suitable animal model in which to study carcinogenesis associated with H. pylori. The aim of our study was to evaluate the accuracy of the serologic test for detecting H. pylori infection in Mongolian gerbils. The model was developed as follows: the H. pylori colony (vacuolating cytotoxin A (+)/cytotoxin-associated gene A (+)) was cultured from the mucosas of previously H. pylori-fed gerbils. These colonies were cultured in broth. Then,we fed the gerbils with 0.5-1 mL of broth (about 10(9) CFU/mL) (intragastric administration) twice within a 3-day period. After inoculation for 6 or 26 weeks, the gerbils were sacrificed and their gastric mucosas were sampled for a series of examinations. Blood samples for serologic testing (STAT-PAK) were collected. H. pylori infection was confirmed. Statistical analysis was performed using the Chi-square test. Differences were regarded as significant when the p value was less than 0.05. A total of 50 gerbils were inoculated with H. pylori and the success rate reached 88%. All 10 gerbils in the control group showed a negative result. Damage to the mucosas was more obvious following increasing periods of inoculation. The rates of sensitivity and specificity, as determined by the STAT-PAK test, were 90.9% and 100%, respectively. The positive and negative predictive values were 100% and 60%, respectively. The STAT-PAK test seemed to be more sensitive and accurate (p < 0.05) in high H. pylori densities. In conclusion, the STAT-PAK test (blood-sampling) showed acceptable results and was suitable for long-term observation of H. pylori infection.