Non-invasive Diagnostic of Helicobacter pylori in Stools by Nested-qPCR

Advances on diagnosis of Helicobacter pylori infections

The association of Helicobacter pylori to several gastric diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer, and its high prevalence worldwide, raised the necessity to use methods for a proper and fast diagnosis and monitoring the pathogen eradication. Available diagnostic methods can be classified as invasive or non-invasive, and the selection of the best relies on the clinical condition of the patient, as well as on the sensitivity, specificity, and accessibility of the diagnostic test. This review summarises all diagnostic methods currently available, including the invasive methods: endoscopy, histology, culture, and molecular methods, and the rapid urease test (RUT), as well as the non-invasive methods urea breath test (UBT), serological assays, biosensors, and microfluidic devices and the stool antigen test (SAT). Moreover, it lists the diagnostic advantages and limitations, as well as the main advances for each methodology. In the end, research on the development of new diagnostic methods, such as bacteriophage-based H. pylori diagnostic tools, is also discussed.

A novel loop-mediated isothermal amplification-lateral flow dipstick method for Helicobacter pylori detection

Introduction

To eradicate Helicobacter pylori (H. pylori) and reduce the risk of gastric cancer, a sensitive, specific, convenient, and simple detection method is needed. This study aimed to establish a novel loop-mediated isothermal amplification-lateral flow dipstick (LAMP-LFD) method for H. pylori detection.

Methods

LAMP primer design software was used to design primers for the conserved sites of the H. pylori ureB gene. UreB-FIP-labeled biotin was used for LAMP amplification, and FAM-labeled probes were specifically hybridized with LAMP amplification products, which were then detected by LFD. In addition, a clinical study was conducted to assess LAMP-LFD in 20 fecal samples.

Results

The results of the optimization indicated that H. pylori could be specifically detected by LFD without cross-reaction with other non-H. pylori bacteria when the LAMP was performed at 65°C for 60 min. The lower limit of the detection method was 10² copies/μL, which was 100 times the sensitivity of polymerase chain reaction (PCR). H. pylori-positive fecal samples were detected by LAMP-LFD in 13/20 patients.

Discussion

In conclusion, a new LAMP-LFD assay has been fully established and confirmed for H. pylori detection. The entire process can be completed in approximately 1.5 h, with the advantages of strong specificity, high sensitivity, and simple operation. This study provides a novel potential method for the detection of H. pylori in the clinical settings of primary hospitals and low-resource countries.