Xiangwen Meng

Detection of Helicobacter pylori gastritis by PCR: correlation with inflammation scores and immunohistochemical and CLOtest findings.

We developed a polymerase chain reaction (PCR) assay to detect Helicobacter pylori in gastric and/or gastroesophageal biopsy specimens of adults with dyspepsia, compared the method with immunohistochemical analysis and CLOtest (Ballard Medical Products, Draper, UT), and correlated the results of each test with the histologic features of infection. H pylori was identified in 36 (60%) of 60 patients irrespective of biopsy site and testing method. In the gastric biopsy specimens, PCR detected H pylori in 29 (52%) of 56 cases, including 11 (100%) of 11 immunohistochemically and/or CLOtest-positive cases. PCR-positive gastric biopsy specimens correlated with a higher average cumulative inflammatory score compared with PCR-negative specimens (P = .001). In gastroesophageal biopsy specimens, PCR detected H pylori in 15 (34%) of 44 cases, including 1 (20%) of 5 immunohistochemically positive specimens. PCR-positive gastroesophageal junction biopsy specimens did not correlate with a higher average cumulative inflammatory score. Overall, PCR detected an additional 23 cases negative by immunohistochemical analysis and/or CLOtest. This PCR assay identified a significant number of H pylori infections that would not be detected by immunohistochemical analysis and/or CLOtest.

Comparing Multiplex PCR and Rapid Urease Test in the Detection of H. pylori in Patients on Proton Pump Inhibitors

Background. This study was conducted to assess the diagnostic value of a multiplex PCR assay to detect H. pylori infection and to further evaluate the negative results from the CLOtest on patients with and without PPI treatment. Methods. This study is a retrospective cohort that included 457 patients with symptoms of dyspepsia, who underwent upper endoscopy at Evanston and Glenbrook Northshore Hospital from June 2003 to October 2007. A total of 556 samples were reported with some patients having more than one test over the time period. The CLOtest was performed first on the gastric specimen and from that specimen, the DNA was isolated and the one-step multiplex PCR was performed. Results. By M-PCR testing, H. pylori was detected in 143 (52.2%) of 274 cases in the control group and 130 (46.1%) of 282 cases in patients on PPI treatment (P = 0.1746). The CLOtest detected the presence of H. pylori in 4 (1.4%) of 282 cases from the same group receiving PPI treatment and 29 (10.6%) of 274 cases from the group not taking a PPI (P ≤ 0.0001). Conclusion. Our PCR is sensitive enough to detect the presence of H. pylori despite being on PPI treatment.