Droplet Digital PCR Detects Low-Density Infection in a Significant Proportion of Helicobacter Pylori -Negative Gastric Biopsies of Dyspeptic Patients
Autor: | María Elisa Quílez, Félix Junquera, Maria Rosa Bella, María José Ramírez-Lázaro, Tamara Parra, Xavier Calvet, Antonia Montserrat, Lorena Garcia-Martinez, Sergio Lario, Alex Casalots |
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Rok vydání: | 2020 |
Předmět: |
Adult
DNA Bacterial Male medicine.medical_specialty Biopsy Urea breath test Rapid urease test Polymerase Chain Reaction Gastroenterology Article Helicobacter Infections law.invention 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Bacterial Proteins law RNA Ribosomal 16S Internal medicine Gastroscopy mental disorders medicine Humans Digital polymerase chain reaction Prospective Studies Helicobacter Dyspepsia Polymerase chain reaction Aged Helicobacter pylori biology medicine.diagnostic_test business.industry Stomach Histology Middle Aged biology.organism_classification Urease Breath Tests chemistry Gastric Mucosa 030220 oncology & carcinogenesis Urea Female 030211 gastroenterology & hepatology business psychological phenomena and processes |
Zdroj: | Dipòsit Digital de Documents de la UAB Universitat Autònoma de Barcelona Clinical and Translational Gastroenterology |
Popis: | Introduction Helicobacter pylori-infected individuals may present low-density infection, undetectable by conventional tests such as histology, rapid urease test, or urea breath test. Droplet digital polymerase chain reaction (ddPCR) is more sensitive than other polymerase chain reaction methods. We aimed to evaluate the ability of ddPCR to detect H. pylori infection in patients diagnosed as negative by conventional tests. Methods Dyspeptic patients (n = 236) were tested for H. pylori by histology, urea breath test, and rapid urease test. Patients were classified as having 3 positive (n = 25, control group), 2 positive (n = 12), one positive (n = 41), or zero positive (n = 158) diagnostic tests. DNA was extracted from gastric biopsies. Triplicate ddPCR testing for each of the 16S rDNA, ureA, and vacA(s) genes was performed using a QX200 ddPCR system (Bio-Rad). A gene was considered positive when detected by at least 2 of 3 repeated ddPCRs. H. pylori positivity was defined as having 2 or more positive genes. Results All the biopsies of the control patients were positive for all 3 16S rDNA, ureA, and vacA(s) genes. H. pylori infection was detected in 57 (36%), 22 (54%), and 9 (75%) patients with zero, 1, and 2 positive diagnostic tests, respectively. The density of infection was 5, 121, 599, and 3,133 copies of H. pylori genome equivalents for patients with zero, 1, and 2 of 3 positive test results and for the control group, respectively. Discussion ddPCR detected low-density "occult" H. pylori infection in a significant proportion (36%) of patients diagnosed as negative by conventional methods. The number of conventional positive tests was related to the density of infection. |
Databáze: | OpenAIRE |
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