Detection of H. pylori in Urease Test Negative Gastric Samples by a Novel Multiplex PCR Assay

Abstract

Purpose: All patients with dyspepsia, either newly or previously diagnosed, should be tested for H. pylori infection. The CLOtest assay is widely used in clinical practice to detect the urease enzyme of H. pylori in gastric mucosal biopsies and many physicians consider it as a gold standard method. However, this is not sensitive enough to diagnose H. pylori infection. We have developed a novel one-step multiplex PCR detection system that can amplify 10 DNA fragments from 5 DNA regions in the genome of H. pylori at the same time. The objective of this study was to assess the diagnostic value of this new multiplex PCR assay to detect H. pylori infection, and further evaluated the negative results from the CLOtest. Methods: This study was performed on the same urease test negative gastric specimen, which had been detected by CLOtest from 276 individuals with dyspepsia symptoms undergoing endoscopy at Evanston Northwestern Healthcare. The CLOtest was performed first and if the result was negative, the negative specimen was collected from the CLOtest gel. From this specimen, the DNA was isolated and was performed the one-step multiplex PCR. Results: Positive results were achieved in 42% (116/276) with multiplex PCR from the H. pylori negative samples tested by CLOtest. Conclusions: Our results indicate that our multiplex PCR method is a highly specific and sensitive method in the detection of H. pylori. The results of H. pylori tested by current methods should be carefully reviewed to ensure that the result is not a false-negative and to obtain the correct diagnosis it would be better that the negative samples of CLOtest were further confirmed by the multiplex PCR assay.