Introduction: Few data on the diagnostic performance of serological tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are currently available. We evaluated sensitivity and specificity of five different widely used commercial serological assays for the detection of SARS-CoV-2–specific IgG, IgM, and IgA antibodies using reverse transcriptase-PCR assay in nasopharyngeal swab as reference standard test.Methods: A total of 337 plasma samples collected in the period April–June 2020 from SARS-CoV-2 RT-PCR positive (n = 207) and negative (n = 130) subjects were investigated by one point-of-care lateral flow immunochromatographic assay (LFIA IgG and IgM, Technogenetics) and four fully automated assays: two chemiluminescence immunoassays (CLIA-iFlash IgG and IgM, Shenzhen YHLO Biotech and CLIA-LIAISON® XL IgG, DiaSorin), one electrochemiluminescence immunoassay (ECLIA-Elecsys® total predominant IgG, Roche), and one enzyme-linked immunosorbent assay (ELISA IgA, Euroimmune).Results: The overall sensitivity of all IgG serological assays was >80% and the specificity was >97%. The sensitivity of IgG assays was lower within 2 weeks from the onset of symptoms ranging from 70.8 to 80%. The LFIA and CLIA-iFlash IgM showed an overall low sensitivity of 47.6 and 54.6%, while the specificity was 98.5 and 96.2%, respectively. The ELISA IgA yielded a sensitivity of 84.3% and specificity of 81.7%. However, the ELISA IgA result was indeterminate in 11.7% of cases.Conclusions: IgG serological assays seem to be a reliable tool for the retrospective diagnosis of SARS-CoV-2 infection. IgM assays seem to have a low sensitivity and IgA assay is limited by a substantial rate of indeterminate results.

Treatment of Helicobacter pylori (H. pylori) infection is a challenge for clinicians. The large increase in drug-resistant strains makes the formulation of new therapeutic strategies fundamental. The frequent onset of side effects during antibiotic treatment (mainly due to intestinal dysbiosis) should not be underestimated as it may cause the interruption of treatment, failure of H. pylori eradication and clonal selection of resistant bacteria. Probiotic integration during antibiotic treatment can exert a dual function: a direct antagonistic effect on H. pylori and a balancing effect on dysbiosis. Therefore, it fulfills the definition of a new therapeutic strategy to successfully treat H. pylori infection. Data reported in literature give promising but discrepant results. Aim: To assess in vitro bacteriostatic and bactericidal activity of probiotic strains against H. pylori. Materials and methods: L. casei, L. paracasei, L. acidophilus, B. lactis and S. thermophilus strains were used. Agar well diffusion and time-kill curves were carried out to detect bacteriostatic and bactericidal activity, respectively. Results: All probiotic strains showed both bacteriostatic and bactericidal activity vs. H. pylori. Conclusions: Such findings prompted us to plan a protocol of treatment in which probiotics are given to infected patients in association with antibiotic therapy.

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Background. Antigens derived from Helicobacter pylori can be used as stool biomarkers to assist in the diagnosis of H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian H. pylori SA chemiluminescent immunoassay against more invasive biopsy tests that are considered to be the “gold standard” (Composite Reference Method). Methods. This prospective multisite study enrolled patients undergoing an esophagogastroduodenoscopy with collection of biopsy and stool specimens. Adult patients (≥22 years) participated in the study from February 2017 to August 2018. Specimens of the stomach were tested by three methods, known as the Composite Reference Method: (1) histological evaluation, (2) culture of the organism, and (3) rapid urease detection test. H. pylori in stool was detected using the automated LIAISON® Meridian H. pylori SA assay, a chemiluminescent immunoassay. Statistical analyses were performed using MedCalc 18.11.6. Results. 277 patients (63% female) were included in the study. The prevalence of infected subjects was 24.2% in this study cohort. Clinical performance assessed against the Composite Reference Method showed very good agreement (Cohen’s kappa=0.922), with good sensitivity (95.5%) and specificity (97.6%). Reproducibility study results showed total imprecision ranging from 3.1% to 13.9% CV. Conclusion. The automated LIAISON® Meridian H. pylori SA assay brings reliable noninvasive testing for H. pylori to the laboratory that is in very good agreement with the current, more invasive biopsy-based methods such as histology, culture, or rapid urease test. The clinical trial identifiers are NCT03060746 (pretherapy) and NCT03060733 (posttherapy).

Cure rate following standard first-line regimens for Helicobacter pylori eradication is decreasing so several patients require two or more treatments. Antibiotic susceptibility-based therapy, advised in current guidelines, is largely impracticable in clinical practice. Some 'standard' regimens (triple therapies based on either levofloxacin or rifabutin, bismuth-based quadruple therapies, sequential, concomitant and hybrid therapies) were empirically used as rescue therapies. We performed a systematic review on recent studies carried out in European countries dealing with these regimens. A total of 24 studies, with 3804 patients, were identified. As second-line therapy, Pylera (89.2%) and sequential therapy (92.5%) achieved significantly higher cure rates as compared to all the other regimens. As third-line therapy, levofloxacin-based therapy (84.1%) and Pylera (83.6%) achieved similarly high cure rates, whereas standard, bismuth-based quadruple therapy (64.1%) achieved the lowest. As a rescue therapy, the success rate was close to 75% following all therapies used, with data on rifabutin-based regimen consolidated in the larger sample size. Overall, levofloxacin-amoxicillin triple therapy achieved higher eradication rates when the 14-rather than 10-day regimen was used (87.1 vs. 72.2%; P = 0.003). Among bismuth-based therapies, Pylera achieved a significantly higher eradication rate than standard quadruple therapy (88 vs. 67%; P < 0.0001). These data suggest that a wise 'therapeutic package' following first-line therapy could be Pylera, levofloxacin-and rifabutin-based therapy, as long as Pylera therapy was not used as a first-line regimen and levofloxacin-based regimen was administered for 14 days. Eur J Gastroenterol Hepatol 33: e66-e70