Diagnosis of Helicobacter pylori infection

Several studies addressed the usefulness of using molecular techniques for the diagnosis of Helicobacter pylori, pointing to the emerging paradigm change for clinical microbiology laboratories. During the last year, new variations of PCR-based approaches (formats, probes), new targets, as well as non-PCR based methods were described. In most cases, molecular methods combine detection of H. pylori with antimicrobial susceptibility testing, to predict antibiotic treatment outcome and guide clinicians in their choice of therapy. Macrolides and fluoroquinolones, for which resistance determinants are well known and are a major cause of treatment failure, remain the main targets of the classical molecular methods. Several other non-molecular methods, based on different technologies, were described for direct or indirect detection of H. pylori in different biological samples. Newly described endoscopic technologies offer advantages in the identification of patients at high risk of developing gastric cancer. Regarding serology, the importance of using optimised serological assays in specific geographical regions, employing local H. pylori strains for preparing antigens was highlighted. Next Generation Sequencing (NGS) based methods appear as a powerful tool to predict antibiotic resistance and will soon lead to a paradigm shift in the transition from culture-based to molecular-based susceptibility testing. In this context, due to the complexity of the resistance mechanisms and to allow the inclusion of further antibiotics, more comprehensive genotypic-phenotypic comparisons are needed. Additionally, the review of papers on H. pylori diagnosis published last year provided information concerning current prevalence of infection and antibiotic resistance in distinct geographies, indicating a tendency towards declining prevalence and rising antibiotic resistance.F.F.V. is funded by Fundação para a Ciência e a Tecnologia through an Assistant Researcher grant CEECIND/03023/2017, and project grants (PTDC/BTM-SAL/28978/2017 and PTDC/BTM-TEC/3238/2020).