New fecal test for non-invasive Helicobacter pylori detection: A diagnostic accuracy study

Helicobacter pylori Secondary Antibiotic Resistance after One or More Eradication Failure: A Genotypic Stool Analysis Study

Helicobacter pylori (H. pylori) antibiotic resistance is the leading cause for unsuccessful eradication therapy. After one or more failures, the chance of encountering secondary antibiotic resistance increases. The aim of this study was to characterize genotypic secondary resistance in a cohort of southern Italian H. pylori patients with at least one previous failure. Such patients collected stool samples using a dedicated kit (THD fecal testTM), and bacterial DNA was extracted and amplified using RT-PCR. Resistance to clarithromycin, amoxicillin, metronidazole, levofloxacin, and tetracycline was assessed using a high-resolution melting curve. We enrolled 50 patients. A total of 72% of patients failed one previous antibiotic course, 16% failed two, 10% failed three, and 2% failed four. The rate of secondary antibiotic resistance was 16% for clarithromycin, 18% for metronidazole, 14% for amoxicillin, 14% for levofloxacin, and 2% for tetracycline. Among the eight clarithromycin-resistant patients, five (62.5%) previously received a clarithromycin-based regimen. The same rate was 33.3% (3/9) for metronidazole. The only tetracycline-resistant patient had received Pylera. In conclusion, our data seem to show that, even though secondary resistance is not very high, resistance to clarithromycin could be very likely related to previous exposure to this antibiotic.

The State of the Art of Molecular Fecal Investigations for Helicobacter pylori (H. pylori) Antibiotic Resistances

A new paradigm shift for the treatment of Helicobacter pylori (H. pylori) infection would be timely due to a progressive increase in antibiotic resistance. Such a shift in the perspective of the H. pylori approach should include the preliminary assessment of antibiotic resistance. However, the availability of sensitivity tests is not widespread and the guidelines have always indicated empirical treatments without taking into account the need to make sensitivity tests accessible, i.e., the necessary starting point for improving results in different geographical areas. Currently, the traditional tools for this purpose (culture) are based on performing an invasive investigation (endoscopy) and often involve technical difficulties; thus, they were only confined to the settings where multiple attempts at eradication have failed. In contrast, genotypic resistance testing of fecal samples using molecular biology methods is much less invasive and more acceptable to patients. The purpose of this review is to update the state of the art of molecular fecal susceptibility testing for the management of this infection and to extensively discuss the potential benefits of their large-scale deployment, i.e., novel pharmacological opportunities.

Effect of metronidazole resistance on Helicobacter pylori eradication regimens

OBJECTIVES

Guidelines suggest bismuth-containing quadruple therapy (BQT) or concomitant therapy (CT) as first-line therapy in our geographic area. Both schedules contain metronidazole. We aimed to evaluate the effect of metronidazole resistance to Helicobacter pylori (H. pylori) eradication therapy.

METHODS

We recruited treatment-naïve subjects with H. pylori infection who received either CT or BQT during January 2020 and December 2021. Before therapy, a fecal sample was collected using the THD fecal test device from each patient. H. pylori DNA was extracted and mutations of rdxA and frxA genes and A2143G for metronidazole and clarithromycin resistance were investigated using real-time polymerase chain reaction with a high-resolution melting curve.

RESULTS

Ninety-six patients were enrolled, including 29 received BQT and 67 received CT. The overall eradication rate was 94.8% (100% for BQT and 92.5% for CT). Metronidazole resistance was found in 18 (18.8%) subjects, while clarithromycin resistance was found in 19 (19.8%). All 18 patients with metronidazole resistance achieved successful eradication (five treated with BQT and 13 with CT). The eradication rate in metronidazole-sensitive strains was 93.6%. Of these, 24 received BQT with 100% success, and 54 had CT with five failures (successful eradication in 90.7%). Two patients with treatment failure were resistant to clarithromycin, and the remaining three were susceptible to both clarithromycin and metronidazole. No statistical significance was observed in the eradication rate between metronidazole-resistant and -sensitive strains (100% vs 93.6%, P = 0.58).

CONCLUSION

Metronidazole resistance does not influence the eradication rate of BQT and CT regimens in our geographical area, even if such results need to confirmed in a larger sample.

Future challenges in gastroenterology and hepatology, between innovations and unmet needs: A SIGE Young Editorial Board's perspective

Gastroenterology, Digestive Endoscopy and Hepatology have faced significant improvements in terms of diagnosis and therapy in the last decades. However, many fields still remain poorly explored, and many questions unanswered. Moreover, basic-science, as well as translational and clinical discoveries, together with technology advancement will determine further steps toward a better, refined care for many gastroenterological disorders in the future. Therefore, the Young Investigators of the Italian Society of Gastroenterology (SIGE) joined together, offering a perspective on major future innovations in some hot clinical topics in Gastroenterology, Endoscopy, and Hepatology, as well as the current pitfalls and the grey zones.

Adherence to international guidelines for the management of Helicobacter pylori infection among gastroenterologists and gastroenterology fellows in Italy: A Survey of the Italian Federation of Digestive Diseases - FISMAD

BACKGROUND

Information on the management of Helicobacter (H.) pylori infection by gastroenterologists and gastroenterology fellows are scarce. We aimed to assess practice of gastroenterologists and gastroenterology fellows and their adherence to guidelines for diagnosis and treatment of H. pylori infection in Italy.

MATERIALS AND METHODS

All gastroenterologists and gastroenterology fellows attending the National Congress of Digestive Diseases - FISMAD were invited to fill-in an on-line questionnaire. The questionnaire included questions on the diagnosis and treatment of H. pylori infection.

RESULTS

A total of 279 gastroenterologists and 61 gastroenterology fellows participated to the study. The ¹³ C-urea breath test was the most preferred method among gastroenterologists and fellows for the diagnosis of H. pylori infection (40.4% and 57.6%, respectively) and the confirmation of eradication (61.3% and 70%, respectively). Sequential therapy was the most preferred first-line treatment of H. pylori for both gastroenterologists and gastroenterology fellows (31.8% and 44%, respectively), followed by bismuth quadruple therapy (31% and 27.6%, respectively) and clarithromycin triple therapy (26.8% and 22.4%, respectively). Only 30% of gastroenterologists and 38.5% of fellows used the clarithromycin triple therapy for the recommended duration of 14 days. Bismuth quadruple therapy was the most preferred second-line therapy for both gastroenterologists and fellows. The majority of gastroenterologists and fellows would prefer an empirical therapy at third line (72.6% and 62.5%, respectively) and a susceptibility-guided therapy at fourth line (46.7% and 71.4%, respectively).

CONCLUSIONS

Practices of gastroenterologists and gastroenterology fellows are in line with guidelines' recommendations, apart for the first-line treatment of H. pylori infection. Targeted educational interventions to improve adherence to guidelines are needed.

Dictionary Learning-Based Ultrasound Image Combined with Gastroscope for Diagnosis of Helicobacter pylori-Caused Gastrointestinal Bleeding

The study is aimed at evaluating the application value of ultrasound combined with gastroscopy in diagnosing gastrointestinal bleeding (GIB) caused by Helicobacter pylori (HP). An ultrasound combined with a gastroscopy diagnostic model based on improved K-means Singular Value Decomposition (N-KSVD) was proposed first. 86 patients with Peptic ulcer (PU) and GIB admitted to our Hospital were selected and defined as the test group, and 86 PU patients free of GIB during the same period were selected as the control group. The two groups were observed for clinical manifestations and HP detection results. The results showed that when the noise ρ was 10, 30, 50, and 70, the Peak Signal to Noise Ratio (PSNR) values of N-KSVD dictionary after denoising were 35.55, 30.47, 27.91, and 26.08, respectively, and the structure similarity index measure (SSIM) values were 0.91, 0.827, 0.763, and 0.709, respectively. Those were greater than those of DCT dictionary and Global dictionary and showed statistically significant differences versus the DCT dictionary (P < 0.05). In the test group, there were 60 HP-positives and 26 HP-negatives, and there was significant difference in the numbers of HP-positives and HP-negatives (P < 0.05), but no significant difference in gender and age (P > 0.05). Of the subjects with abdominal pain, HP-positives accounted for 59.02% and HP-negatives accounted for 37.67%, showing significant differences (P < 0.05). Finally, the size of the ulcer lesion in HP-positives and HP-negatives was compared. It was found that 71.57% of HP-positives had ulcers with a diameter of 0-1 cm, and 28.43% had ulcers with a diameter of ≥1 cm. Compared with HP-negatives, the difference was statistically significant (P < 0.05). In conclusion, N-KSVD-based ultrasound combined with gastroscopy demonstrated good denoising effects and was effective in the diagnosis of GIB caused by HP.

Molecular detection of Helicobacter pylori and clarithromycin resistance in gastric biopsies: a prospective evaluation of RIDA®GENE Helicobacter pylori assay

Background: Empirical treatment of Helicobacter pylori (HP) depends on the local prevalence of clarithromycin resistance but data are lacking and culturing of HP is time-consuming. We evaluated RIDA®GENE Helicobacter pylori assay (r-biopharm), a quantitative PCR assay for detecting HP and clarithromycin resistance mutations in gastric biopsies.Material/methods: Gastric biopsies were obtained from each of 436 consecutive patients referred for gastroscopic investigation and results of qPCR were compared to culture and immunohistochemical staining (IHCS).Results: Of 436 samples, 47 were positive for HP by PCR (11%), 42 by culture (9.7%) and 44 by IHCS (10%). Compared to culture, sensitivity and specificity of the qPCR were 100% and 99%, respectively, and 96% and 99% compared to IHCS. The sensitivity and specificity for clarithromycin resistance detection were 92% and 97%, respectively.Conclusions: RIDA®GENE Helicobacter pylori assay reliably and rapidly detects HP and its resistance to clarithromycin in human gastric biopsies.

Primary antibiotic resistance of Helicobacter pylori isolates is twofold more frequent in HIV-positive than HIV-negative individuals: A descriptive observational study

The antimicrobial susceptibility of Helicobacter pylori strains isolated from HIV-positive individuals is not well characterized. This study aimed to measure the prevalence and long-term trends associated with primary H. pylori antibiotic resistance, evaluate correlations with antibiotic consumption, and compare predictors for H. pylori antibiotic resistance between HIV-positive and HIV-negative individuals. In this longitudinal registry study, we evaluated consecutive adults with and without HIV infection, naïve to H. pylori treatment, who underwent upper gastrointestinal endoscopy and had a positive H. pylori culture, with susceptibility testing available, between 2004 and 2015. Outpatient antibiotic consumption data were based on nationwide aggregated numbers. H. pylori was isolated from gastric biopsies of 3008/8321 patients, 181/477 (37.9%) were HIV-positive and 2827/7844 (36.0%) HIV-negative. Overall cohort mean prevalence of H. pylori primary antibiotic resistance was 11.1% for clarithromycin, 17.8% levofloxacin, and 39.4% metronidazole. The prevalence of H. pylori primary resistance was significantly higher for these three drugs in HIV-positive individuals across the study period. Linear regression showed that the prevalence of clarithromycin and levofloxacin resistance correlated with the country aggregate daily dose consumption of macrolides and quinolones, respectively. Multivariable regression analysis showed that HIV infection is a strong independent risk factor for multiple H. pylori antibiotic resistance. In summary, HIV infection is a risk factor for carrying multi-resistant H. pylori strains and this is correlated with antibiotic consumption. Empirical therapies should be avoided in HIV-positive individuals. These data highlight the need to implement ongoing monitoring of H. pylori antimicrobial susceptibility among HIV-positive individuals. The study is registered at ISRCTN registry, number 13466428: https://www.isrctn.com/ISRCTN13466428.

What Is New in Helicobacter pylori Diagnosis. An Overview

Helicobacter pylori infection remains one of the most prevalent infections worldwide, especially in low-resource countries, and the major risk factor for peptic ulcer and gastric cancer. The “test-and-treat” strategy is recommended by several guidelines and consensus. The choice of testing method is based on patient age, presence of alarm signs and/or symptoms, use of non-steroidal anti-inflammatory drugs, as well as local availability, test reliability, and cost. Culture is the gold standard to detect H. pylori and, possibly, to perform susceptibility testing, however, it requires upper endoscopy and dedicated labs. Recent advances in molecular biology have provided new strategies in detecting infection and antimicrobial resistance without invasive tests. In this review we attempt to offer a comprehensive panorama on the new diagnostic tools and their potential use in clinical settings, in order to accomplish specific recommendations.

Polymerase chain reaction-based tests for detecting Helicobacter pylori clarithromycin resistance in stool samples: A meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is closely associated with the etiology of a variety of gastric diseases. The effective eradication of H. pylori infection has been shown to reduce the incidence of gastric carcinoma. However, the rate of H. pylori eradication has significantly declined due to its increasing resistance to antibiotics, especially to clarithromycin. Therefore, the detection of clarithromycin resistance is necessary prior to the treatment of H. pylori. Although many studies have been conducted on the use of polymerase chain reaction (PCR)-based tests to detect clarithromycin resistance in stool samples, no accurate data on the feasibility of these tests are available. Here, we performed a meta-analysis to assess the feasibility of these noninvasive tests.

AIM

To evaluate the reliability of PCR-based tests for detecting H. pylori clarithromycin resistance in stool samples.

METHODS

We searched PubMed, Medline, Embase, and other databases for articles that evaluated the value of the PCR analysis of stool samples for detecting the resistance of H. pylori to clarithromycin. We collected cross-sectional studies that met the inclusion criteria. Diagnostic accuracy measures were pooled using a random-effects model. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Subgroup analysis was also conducted according to PCR type, purification technique, reference standard, mutation site, sample weight, number of patients, and age group, and the clinical utility of diagnostic tests was evaluated using the Likelihood Ratio Scatter Graph.

RESULTS

Out of the 1818 identified studies, only 11 met the eligibility criteria, with a total of 592 patients assessed. A meta-analysis of the random-effect model showed that PCR-based analysis of stool samples had high diagnostic accuracy for detecting clarithromycin resistance in patients infected with H. pylori. The combined sensitivity was 0.91 [95% confidence interval (CI): 0.83-0.95], Q = 30.34, and I² = 67.04, and the combined specificity was 0.97 (95%CI: 0.62-1.00), Q = 279.54, and I² = 96.42. The likelihood ratio for a positive test was 33.25 (95%CI: 1.69-652.77), and that for a negative test was 0.10 (95%CI: 0.05-0.18), with an area under the curve of 0.94. The diagnostic odds ratio was 347.68 (95%CI: 17.29-6991.26). There was significant statistical heterogeneity, and the sub-analyses showed significant differences in the number of patients, sample weight, purification methods, PCR types, mutation points, and reference standards. The included studies showed no risk of publication bias.

CONCLUSION

PCR-based tests on stool samples have high diagnostic accuracy for detecting H. pylori clarithromycin resistance.

Molecular Detection of Antibiotic-Resistant Helicobacter pylori

Antimicrobial susceptibility testing (AST) for H. pylori is essential to accurately assess the prevalence of antibiotic resistance in each population. Antibiotic resistance rates form the basis of local guidelines for H. pylori treatment and AST may also be used as a personalized medicine approach to tailor therapy. This chapter provides an update on global antibiotic resistance rates and describes molecular mechanisms that confer H. pylori antibiotic resistance. An overview on the advantages and limitations of molecular AST using both invasive and noninvasive approaches is also provided.

Helicobacter pylori Primary and Secondary Genotypic Resistance to Clarithromycin and Levofloxacin Detection in Stools: A 4-Year Scenario in Southern Italy

Antibiotic resistance has become an emerging problem for treating Helicobacter pylori (H. pylori) infection. Clarithromycin and levofloxacin are two key antibiotics used for its eradication. Therefore, we reviewed our experience with genotypic resistance analysis in stools to both clarithromycin and levofloxacin in the last four years to evaluate time trends, both in naive and failure patients. Patients collected a fecal sample using the THD fecal test device. Real-time polymerase chain reaction was performed to detect point mutations conferring resistance to clarithromycin (A2142C, A2142G, and A2143G in 23S rRNA) and levofloxacin (substitutions at amino acid position 87 and 91 of gyrA). One hundred and thirty-five naive patients were recruited between 2017-2020. Clarithromycin resistance was detected in 37 (27.4%). The time trend did not show any significant variation from 2017 to 2020 (p = 0.33). Primary levofloxacin resistance was found in 26 subjects (19.2%), and we observed a dramatic increase in rates from 2017 (10%) to 2018 (3.3%), 2019 (20%), and 2020 (37.8%). Ninety-one patients with at least one eradication failure were recruited. Secondary resistance to clarithromycin and levofloxacin was found in 59 (64.8%) and 45 patients (59.3%), respectively. In conclusion, our geographic area has a high risk of resistance to clarithromycin. There is also a progressive spreading of levofloxacin-resistant strains.

Clinical impact of vonoprazan-based dual therapy with amoxicillin for H. pylori infection in a treatment-naïve cohort of junior high school students in Japan

BACKGROUND

Although 7-day triple therapy, consisting of vonoprazan, amoxicillin (AMO), and clarithromycin (CLA), is recommended for Helicobacter pylori (H. pylori) eradication in adults. However, the importance of reducing antibiotic use in pediatric patients is well recognized. Therefore, our aim was to compare the effectiveness and safety of vonoprazan and AMO (VA) dual therapy to vonoprazan-based (VAC) triple therapy for H. pylori eradication in a cohort of treatment-naïve junior high school students in Japan.

METHODS

This was a prospective observational study of second-year junior high-school students in Yurihonjo and Nikaho Cities, Japan. Between 2015 and 2017, 161 students were treated with VAC-triple therapy (20 mg vonoprazan, 750 mg AMO, and 200 mg CLA, twice a day for 7 days), while 60 students were treated with VA-dual therapy (20 mg vonoprazan and 750 mg AMO, twice a day for 7 days) since 2018. The success rate of H. pylori eradication and drug-related adverse events were compared between the two therapy groups. Intention-to-treat (ITT) and per-protocol (PP) analyses were performed.

RESULTS

Groups were comparable at baseline. The ITT and PP eradication rates were 85.0% (95% confidence interval [CI] 75.8-94.2%) and 86.4% (95% CI 77.4-95.5%), respectively, with VA-dual therapy and 82.0% (95% CI 76.0%-87.9%) and 84.1% (95% CI 78.3-89.8%), respectively, with VAC-triple therapy. VA-dual therapy was non-inferior to VAC-triple therapy (ITT, p = 0.018; PP, p = 0.020). The adverse event rate was 10.0% with VA-dual therapy and 19.8% with VAC-triple therapy (p = 0.108).

CONCLUSIONS

The effectiveness of VA-dual therapy was comparable to that of VAC-triple therapy in H. pylori treatment-naïve junior high school students, while reducing the use of antibiotics.

Application of gene chip technology in the diagnostic and drug resistance detection of Helicobacter pylori in children

BACKGROUND AND AIMS

Helicobacter pylori (HP) culture for diagnosing HP infection is time-consuming and technologically complex. This study evaluated the clinical significance of gastric mucosal gene chip technology in the rapid diagnosis of HP infection and detection of drug resistance in children.

METHODS

Patients (between the age of 2.5 and 16.0 years old) manifesting gastrointestinal symptoms were enrolled in this study. HP culture of gastric mucosa and drug sensitivity test were performed. A gene chip of gastric mucosa was used to detect the presence of HP infection, some single nucleotide polymorphisms in HP drug resistance genes, or associated gene mutation. DNA sequencing was investigated and compared with the gene chip test results.

RESULTS

Out of 267 cases, HP culture was positive in 169 cases and negative in 98 cases. HP detection by the gene chip method was positive in 208 cases and negative in 59 cases. The sensitivity, specificity, and accuracy of the gene chip technology for diagnosing HP infection were 96.1, 85.0, and 93.6%, respectively. HP resistance gene locus using the gene chip showed the main mutation locus of clarithromycin to be 2143A/G, levofloxacin at locus GyrA 91 and GyrA 87, and amoxicillin at PBP1 556ser. Concordance rates between gene chip and DNA sequencing for VacA-S/M, 16S rRNA, 23S rRNA, and GyrA were greater than 95%, and that of PBP1 was greater than 82%.

CONCLUSION

Gastric mucosal gene chip technology can be used for rapid diagnosis and drug resistance detection of HP infection in children.

Update on the Management of Helicobacter pylori Infection

Purpose of review

Our purpose was to provide an update on methods and indications for testing and treatment selection focusing on novel modalities.

Recent findings

Increasing antibiotic resistance has reduced treatment effectiveness. Antibiotic resistance testing is not widely available in North America where there are insufficient resistance and susceptibility data. Quadruple regimens (bismuth-based or concomitant/non-bismuth-based) have been recommended first-line. A rifabutin-based combination product recently approved by the US Food and Drug Administration is highly effective and should simplify treatment. The potassium-competitive acid blocker vonoprazan is being evaluated as part of dual or triple combination regimens. Molecular-based genotypic testing for antibiotic resistance and an effective H. pylori vaccine remain under development.

Summary

Inability to test for antibiotic resistance renders treatment selection empiric. However, resistance to rifabutin and amoxicillin remains rare. Effective management continues to comprise appropriate diagnostic testing for active infection, utilization of an effective regimen, and post-treatment testing.

The Puzzle of Coccoid Forms of Helicobacter pylori: Beyond Basic Science.Antibiotics (Basel). 2020;9. [PMID: 32486473 DOI: 10.3390/antibiotics9060293]

Helicobacter pylori (H. pylori) may enter a non-replicative, non-culturable, low metabolically active state, the so-called coccoid form, to survive in extreme environmental conditions. Since coccoid forms are not susceptible to antibiotics, they could represent a cause of therapy failure even in the absence of antibiotic resistance, i.e., relapse within one year. Furthermore, coccoid forms may colonize and infect the gastric mucosa in animal models and induce specific antibodies in animals and humans. Their detection is hard, since they are not culturable. Techniques, such as electron microscopy, polymerase chain reaction, loop-mediated isothermal amplification, flow cytometry and metagenomics, are promising even if current evidence is limited. Among the options for the treatment, some strategies have been suggested, such as a very high proton pump inhibitor dose, high-dose dual therapy, N-acetycysteine, linolenic acid and vonoprazan. These clinical, diagnostic and therapeutic uncertainties will represent fascinating challenges in the future.

Optimizing proton pump inhibitors in Helicobacter pylori treatment: Old and new tricks to improve effectiveness

The survival and replication cycle of Helicobacter pylori (H. pylori) is strictly dependant on intragastric pH, since H. pylori enters replicative phase at an almost neutral pH (6-7), while at acid pH (3-6) it turns into its coccoid form, which is resistant to antibiotics. On these bases, it is crucial to increase intragastric pH by proton pump inhibitors (PPIs) when an antibiotic-based eradicating therapy needs to be administered. Therefore, several tricks need to be used to optimize eradication rate of different regimens. The administration of the highest dose as possible of PPI, by doubling or increasing the number of pills/day, has shown to be able to improve therapeutic outcome and has often proposed in rescue therapies, even if specific trials have not been performed. A pre-treatment with PPI before starting antibiotics does not seem to be effective, therefore it is discouraged. However, the choice of PPI molecule could have a certain weight, since second-generation substances (esomeprazole, rabeprazole) are likely more effective than those of first generation (omeprazole, lansoprazole). A possible explanation is due to their metabolism, which has been proven to be less dependent on cytochrome P450 (CYP) 2C19 genetic variables. Finally, vonoprazan, a competitive inhibitor of H+/K+-ATPase present on luminal membrane of gastric parietal cells has shown the highest efficacy, due to both its highest acid inhibition power and rapid pharmacologic effect. However current data come only from Eastern Asia, therefore its strong power needs to be confirmed outside this geographic area in Western countries as well as related to the local different antibiotic resistance rates.

Review: Diagnosis of Helicobacter pylori infection

Endoscopic imaging of the stomach is improving. In addition to narrow band imaging, other methods, for example, blue light imaging and linked color imaging, are now available and can be combined with artificial intelligence systems to obtain information on the gastric mucosa and detect early gastric cancer. Immunohistochemistry is only recommended as an ancillary stain in case of chronic active gastritis without Helicobacter pylori detection by standard staining, and recommendations to exclude false negative H. pylori results have been made. Molecular methods using real-time PCR, droplet digital PCR, or amplification refractory mutation system PCR have shown a high accuracy, both for detecting H. pylori and for clarithromycin susceptibility testing, and can now be used in clinical practice for targeted therapy. The most reliable non-invasive test remains the ¹³ C-urea breath test. Large data sets show that DOB values are higher in women and that the cut-off for positivity could be decreased to 2.74 DOB. Stool antigen tests using monoclonal antibodies are widely used and may be a good alternative to UBT, particularly in countries with a high prevalence of H. pylori infection. Attempts to improve serology by looking at specific immunodominant antigens to distinguish current and past infection have been made. The interest of Gastropanel^® which also tests pepsinogen levels was confirmed.

Novel high resolution melt curve assay for the analysis of predominance of Helicobacter pylori clarithromycin resistance

Clarithromycin resistance is the most common cause of Helicobacter pylori treatment failure and it is attributed to three point mutations, A2142G, A2142C and A2143G, within the 23S rRNA gene. We aimed to determine the prevalence of H. pylori clarithromycin resistance using a novel high resolution melt assay. A total of 151 stool samples were collected from treatment-naïve patients with general gastric discomfort who also performed 13CO2 breath tests. Stool antigen tests were also performed on 126 of the 151 stool samples collected. Bacterial DNA was extracted from the stool and analyzed by comparing it with four reference plasmids incorporating the three mutations and the wild type (WT) sequences. The melt assay detected 106 H. pylori positive samples, of which 54 had a WT sequence, and 52 had a point mutation associated with clarithromycin resistance, including A2142G in 10, A2142C in 13, A2143G in 18 and heterozygosity (multiple peaks) in 11. Compared with the gold standards (13CO2 breath and stool antigen tests), the melt assay had a sensitivity of 100% and 99% and a specificity of 82% and 78%, respectively. Therefore, our stool-based molecular assay is able to identify H. pylori infection and clarithromycin resistance. It could be used for screening prior to administration of clarithromycin eradication therapy.

Development of Helicobacter pylori treatment: How do we manage antimicrobial resistance?

Helicobacter pylori (H. pylori) antimicrobial resistance is an urgent, global issue. In 2017, the World Health Organization designated clarithromycin-resistant H. pylori as a high priority bacterium for antibiotic research and development. In addition to clarithromycin, resistance to metronidazole and fluoroquinolones has also increased worldwide. Recent international guidelines for management of H. pylori infection recommend bismuth or non-bismuth quadruple therapy for 14 d as a first-line treatment for H. pylori in areas of high clarithromycin and/or metronidazole resistance. Although these treatment regimens provide acceptable H. pylori eradication rates, the regimens used should not contribute to future resistance of H. pylori to antimicrobials. Moreover, these regimens can promote resistance, due to prolonged therapy with multiple antibiotics. A new strategy that can eradicate H. pylori as well as reduce the antibiotics used is required to prevent future antimicrobial resistance in H. pylori. Dual-therapy with vonoprazan and amoxicillin could be a breakthrough for H. pylori eradication in an era of growing antimicrobial resistance. This regimen may provide a satisfactory eradication rate of H. pylori and also minimize antimicrobial resistance due to single antibiotic use and the strong inhibitory effect of vonoprazan on gastric acid secretion.

Non-malignant Helicobacter pylori-Associated Diseases

Helicobacter pylori infection of the human stomach is associated with chronic gastritis, peptic ulcer disease or gastric carcinoma, and thus a high burden for the public health systems worldwide. Fortunately, only a small subfraction of up to 15-20% of infected individuals will develop serious complications. Unfortunately, it is not always known upfront, who will be affected by serious diesease outcome. For risk stratifications, it is therefore necessary to establish a common terminology and grading system, that can be applied worldwide to compare population data. The updated Sydney System for classification of gastritis with its semi-quantitative analogue scale is the system, that is currently used worldwide. Additionally, pathologists should always try to classify the etiology of the inflammatory infiltrates in the stomach to instruct the clinicians for choosing a proper treatment regime. Risk factors such as intestinal metaplasia, atrophy and scoring systems to classify these risk factors into a clinical context such as OLGA and OLGIM are discussed. Also, special forms of gastritis like lymphocytic gastritis, autoimmune gastritis and peptic ulcer disease are explained and discussed e.g. how to diagnose and how to treat. Extra-gastric sequelae of H. pylori infections inside and outside the stomach are shown in this chapter as well. Important host and bacterial risk factors such as pathogenicity islands are dicussed to draw a complete landscape around a H. pylori infection, that still can be diagnosed in patients. However, it needs to be noted that some countries have almost no H. pylori infection anymore, while others have still a very high frequency of infections with or without serious complications. The understanding and application of risk assessements may help to save money and quality of life. Extra-gastric H. pylori infections are rarely reported in the literature until today. The pathogenitiy is still under debate, but especially in the bile ducts and gallbladder, several pathological conditions may be also based on H. pylori infection, and will be also discussed.