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

Abstract

The aim of this study was to develop a non-invasive diagnostic test for the detection of Helicobacter pylori in stool samples from digestive symptomatic patients, using a new protocol of nested-qPCR. A total of 143 patients were invited to participate in the study. A gastric biopsy of each patient was collected for Rapid Urease Testing (RUT) and histology by Giemsa stain. A fecal sample for nested-qPCR analysis was also obtained. DNA was extracted from the fecal samples, and conventional PCR followed by qPCR of the ureC gene of H. pylori was carried out. We evaluated the presence of H. pylori, in 103 females and 40 males, mean (± SD) age of 56.5 ± 14.18. The sensitivity of RUT to detect the infection was 67.0% (95% C.I.: 57.2 - 75.8) and specificity was 92.3% (95% C.I.: 76.5 - 99.1). Histology by Giemsa stain, commonly used as a reference for H. pylori detection, showed a sensitivity of 98.6% (95% C.I.: 92.5 - 100.0) and a specificity of 89.7% (95% C.I.: 72.7 - 97.8). In contrast, detection of H. pylori infection in stools by nested-qPCR showed a sensitivity of 100% (95% C.I.: 94.9 - 100.0) and a specificity of 83.9% (95% C.I.: 66.3 - 94.6). Our test, based in nested-qPCR is a better diagnostic alternative than conventional RUT, and is similar to histology by Giemsa stain in the detection of H. pylori, by which the test could be used for non-invasive diagnosis in clinical practice.

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

“…In summary, the method takes advantage of the high sensitivity and specificity of LAMP, as well as the ease of display and safety of LFD. Although various molecular detection methods for H. pylori have been developed in recent years (Molnar et al, 2008 ; Taborda et al, 2018 ; Ji et al, 2020 ), these methods require special instruments, such as PCR, fluorescent quantitative PCR, and high-throughput sequencing, which restrict the implementation of H. pylori detection in primary hospitals or low-resource countries. Compared with other molecular methods, LAMP-LFD has the advantages of simplicity, fast operation, minimal experimental equipment requirements, less consumables, and intuitive results.…”

Prevalencia de cepas cagA-positivo en la región de Coquimbo, determinada mediante nested-qPCR en muestras fecales

“…En este trabajo evaluamos la presencia de cepas cagA-positivo entre aquellos pacientes infectados con H. pylori en la región de Coquimbo, mediante nested-qPCR, a partir de DNA extraído desde muestras fecales 15 . Entre 160 pacientes con sintomatología digestiva, encontramos 123 en los cuales la Histología (Giemsa) detectó la bacteria, mientras que esta cifra aumentó a 129 pacientes cuando se utilizó nested-qPCR para el gen ureC.…”

“…Recientemente, nuestro laboratorio ha desarrollado un método diagnóstico, basado en nested-qPCR, para determinar la presencia de H. pylori en muestras fecales humanas 15 . Este método diagnóstico, que mide la presencia del gen ureC, posee una solicitud de patente, la que se encuentra bajo el Nº 2016-01214, en INAPI (Instituto Nacional de Propiedad Industrial).…”