Culture and real time-PCR in detection of Helicobacter pylori in gastric antrum mucosal specimen

  Objective   To evaluate the consistency of two diagnostic methods (isolation culture and real time-PCR) that are commonly used in detection of Helicobacter pylori (H. pylori) in gastric antrum mucosal specimen.

  Methods  Four hospitals in Xiaoshan, Wenling, Cangnan, and Huzhou in Zhejiang province were selected. From November 16, 2020 to December 7, 2020, a total of 1 312 gastric antrum mucosal specimens were collected from the four hospitals and submitted to Zhiyuan Medical Laboratory in Hangzhou. Each specimen was processed in duplicate and subjected to H. pylori isolation and real time-PCR detection (cagH as target) in a parallel and double-blind manner. Pearson's χ² test, Fisher's exact test, McNemar's paired χ² test, independent-sample t-test, and other related statistical methods were used to analyze the consistency of the two methods and the differences among the four hospitals.

  Results  The H. pylori positive rate of culture was 29.34% (385/1 312) and the H. pylori positive rate of real time-PCR was 28.51% (374/1 312), the difference was not significant (P=0.636). The positive rates of the two methods had no significant difference among the specimens from four hospitals respectively (P＞0.05), and the Kappa values were 0.84, 0.89, 0.75, 0.91 and 0.85 in the specimens from Xiaoshan, Wenling, Cangnan, Huzhou hospitals and in all specimens, respectively. The sensitivity and specificity of the real time-PCR were 89.26% and 100.00%. Among the real time-PCR single positive samples, the range of Ct value was from 25.47 to 34.97, with a mean value of 30.90. There were 90% Ct values no more than 34.46 and the highest frequency group was the 29.00–30.00 group.

  Conclusion  Both the cultural and real time-PCR could achieve high detection efficacy in the detection of H. pylori in clinical gastric antrum mucosal specimen. The results of both methods had good consistency, and each single method had good reliability. The content of H. pylori in specimen and specimen transportation method might have significant effects on results.