How antibiotic resistances could change Helicobacter pylori treatment: A matter of geography?

Review of Methods for Detection Helicobacter pylori in Kazakhstan

Helicobacter pylori (H. pylori) infection can cause a wide range of gastrointestinal disorders, including chronic nonatrophic gastritis, multifocal atrophic gastritis, peptic ulcer disease, gastric adenocarcinoma, and extra-nodal B-cell lymphoma. Although the prevalence of H. pylori infection has decreased among adults, it is still very common. Approximately 90% of gastric adenocarcinomas are associated with H. pylori infection. Despite the established link between H. pylori infection and noncardiac gastric cancer, and the increasing incidence of gastric cancer in Kazakhstan, there are limited data on the prevalence of H. pylori in the country. This may be due to the difficulty of detecting H. pylori and the unavailability of diagnostic methods. This review presents the current data of diagnostic tests for the detection of H. pylori in Kazakhstan with a focus on limitations and practical significance.

Experience of Metronidazole Triple Therapy After Clarithromycin Triple Therapy Failure for Helicobacter pylori Eradication in Korea

Background/Objectives: Bismuth quadruple therapy (BQT) is recommended as the best second-line regimen after failure of first-line clarithromycin triple therapy (CTT) for Helicobacter pylori eradication. However, there are some limitations to this approach, including the lack of an appropriate sequel regimen after failure of BQT and complicated administration. Metronidazole triple therapy (MTT) is simple to administer, but it is not widely recommended. This study was conducted to determine the efficacy of MTT as second-line regimen for H. pylori eradication after failure of CTT. Methods: We retrospectively reviewed the medical records of the Korean patients with H. pylori infection who underwent second-line treatment after failure of first-line CTT from October 2013 to October 2019. The efficacy of MTT and BQT for H. pylori eradication was compared. Results: The eradication rate in the BQT group tended to be higher than that in the MTT group; however, the difference was not statistically significant (208/233, 89.3% versus 244/284, 85.9%, p = 0.287). Among 40 patients with second-line MTT eradication failure, 21 received the third-line BQT, and 15 showed successful eradication (15/21, 71.4%). In the men 70 years or older, the eradication rate of MTT was lower than that of BQT without statistical significance (75.8% versus 94.1%, p = 0.141). Conclusions: These findings suggested that MTT could be a second-line treatment option, reserving BQT for Helicobacter pylori eradication after first line CTT failure, except in elderly men 70 years or older.

Helicobacter pylori: Routes of Infection, Antimicrobial Resistance, and Alternative Therapies as a Means to Develop Infection Control

Helicobacter pylori (H. pylori) is a Gram-negative, spiral-shaped bacterium that colonizes the gastric epithelium and is associated with a range of gastrointestinal disorders, exhibiting a global prevalence of approximately 50%. Despite the availability of treatment options, H. pylori frequently reemerges and demonstrates increasing antibiotic resistance, which diminishes the efficacy of conventional therapies. Consequently, it is imperative to explore non-antibiotic treatment alternatives to mitigate the inappropriate use of antibiotics. This review examines H. pylori infection, encompassing transmission pathways, treatment modalities, antibiotic resistance, and eradication strategies. Additionally, it discusses alternative therapeutic approaches such as probiotics, anti-biofilm agents, phytotherapy, phototherapy, phage therapy, lactoferrin therapy, and vaccine development. These strategies aim to reduce antimicrobial resistance and enhance treatment outcomes for H. pylori infections. While alternative therapies can maintain low bacterial levels, they do not achieve complete eradication of H. pylori. These therapies are designed to bolster the immune response, minimize side effects, and provide gastroprotective benefits, rendering them suitable for adjunctive use alongside conventional treatments. Probiotics may serve as adjunctive therapy for H. pylori; however, their effectiveness as a monotherapy is limited. Photodynamic and phage therapies exhibit potential in targeting H. pylori infections, including those caused by drug-resistant strains, without the use of antibiotics. The development of a reliable vaccine is also critical for the eradication of H. pylori. This review identifies candidate antigens such as VacA, CagA, and HspA, along with various vaccine formulations, including vector-based and subunit vaccines. Some vaccines have demonstrated efficacy in clinical trials, while others have shown robust immune protection in preclinical studies. Nevertheless, each of the aforementioned alternative therapies requires thorough preclinical and clinical evaluation to ascertain their efficacy, side effects, cost-effectiveness, and patient compliance.

Eradication rate and safety of vonoprazan-amoxicillin dual therapy for helicobacter pylori eradication: a randomized controlled trial

BACKGROUND

Helicobacter pylori (H. pylori), prevalent in developing regions, is a key factor in gastrointestinal diseases. Despite the common use of bismuth-based quadruple therapy, its drawbacks have prompted the search for alternatives. Recently, vonoprazan, a novel acid suppressant, has shown promise in combination with antibiotics as a dual therapy for H. pylori eradication. This study aimed to assess the therapeutic outcomes and adverse events of vonoprazan-amoxicillin dual therapy compared to quadruple therapy.

METHODS

A randomized controlled trial (RCT) enrolled H. pylori-infected patients at Zhejiang Hospital. Participants were randomly assigned to dual and quadruple therapy groups. The primary endpoints were H. pylori eradication and adverse events.

RESULTS

Of the 400 patients studied from April 2022 to June 2023, In the intention-to-treat (ITT) analysis, the eradication rates of H. pylori in vonoprazan-amoxicillin dual therapy group and quadruple therapy group were 94.0% and 87.0%, respectively, p = 0.017. In the per-protocol (PP) analysis were 97.9% and 93.0%, p = 0.022. Additionally, the dual therapy group had a significantly lower incidence of adverse events (19%) compared to the quadruple therapy group (53%) (p < 0.001).

CONCLUSION

Vonoprazan-amoxicillin dual therapy demonstrates superior eradication efficacy and reduced adverse events compared to quadruple therapy in H. pylori-infected patients, suggesting its potential for clinical application and promotion.

Role of MIC levels and 23S rRNA mutation sites to clarithromycin in 14-day clarithromycin bismuth quadruple therapy for Helicobacter pylori eradication: A prospective trial in Beijing

Background

Rising clarithromycin resistance undermines Helicobacter pylori (H. pylori) treatment efficacy. We aimed to determine clarithromycin's minimum inhibitory concentration (MIC) levels and identify specific mutation sites in the 23S ribosomal subunit (23S rRNA) that predict treatment outcomes in a 14-day regimen of clarithromycin bismuth quadruple therapy (amoxicillin 1g, clarithromycin 500 mg, rabeprazole 10 mg, and colloidal bismuth pectin 200 mg).

Materials and methods

We included adult H. pylori patients who hadn't previously undergone clarithromycin-based treatment, either as initial or rescue therapy. Exclusions were made for penicillin allergy, recent use of related medications, severe illnesses, or inability to cooperate. Patients underwent a 14-day clarithromycin bismuth quadruple therapy. Gastric mucosa specimens were obtained during endoscopy before eradication. MIC against amoxicillin and clarithromycin was determined using the E-test method. The receiver operating characteristic (ROC) curve helped to find the optimal clarithromycin resistance MIC breakpoint. Genetic sequences of H. pylori 23S rRNA were identified through Sanger Sequencing. (ChiCTR2200061476).

Results

Out of 196 patients recruited, 92 met the inclusion criteria for the per-protocol (PP) population. The overall intention-to-treat (ITT) eradication rate was 80.00 % (84/105), while the modified intention-to-treat (MITT) and PP eradication rates were 90.32 % (84/93) and 91.30 % (84/92) respectively. No amoxicillin resistance was observed, but clarithromycin resistance rates were 36.19 % (38/105), 35.48 % (33/93), and 34.78 % (33/92) in the ITT, MITT, and PP populations respectively. Compared with the traditional clarithromycin resistance breakpoint of 0.25 μg/mL, a MIC threshold of 12 μg/mL predicted better eradication. Among 173 mutations on 152 sites in the 23S rRNA gene, only the 2143A > G mutation could predict eradication outcomes (p < 0.000).

Conclusions

Interpretation of elevated MIC values is crucial in susceptibility testing, rather than a binary "susceptible" or "resistant" classification. The 2143A > G mutation has limited specificity in predicting eradication outcomes, necessitating further investigation into additional mutation sites associated with clarithromycin resistance.

A pilot study evaluating high dose esomeprazole, bismuth subcitrate and amoxicillin for eradicating Helicobacter pylori infection in Iran

BACKGROUND

Helicobacter pylori (H. pylori) is strongly associated with peptic ulcer disease and gastric cancer. We evaluated two triple therapy regimens comprising esomeprazole, high dose bismuth, and different doses of amoxicillin for first-line H. pylori eradication.

MATERIALS AND METHODS

Two hundred patients with dyspepsia and naive H. pylori infection were randomly assigned into two groups (n = 100). Both groups were treated for 14 days similarly with esomeprazole (40 mg, twice daily) and bismuth subcitrate (240 mg, three times daily), but the dose of amoxicillin was varied between Groups A (750 mg) and B (1000 mg) three times daily. Treatment compliance and side effect were evaluated following the therapies and after 8 weeks, a negative test of stool H. pylori antigen confirmed eradication.

RESULTS

The two groups were comparable with respect to sex and age. According to intention to treat analysis, eradication rates were 80% (95% CI: 77.2%-82.8%) and 90% (95% CI: 84.1%-95.9%) in A and B groups, respectively (p = 0.22). Per-protocol eradication rates were 87% (95% CI: 80.4%-93.6%) and 92.8% (95% CI: 87.7%-97.9%), respectively (p = 0.23). Severe adverse effects were 3% and 2%, respectively (p = 0.34).

CONCLUSION

High dose esomeprazole, amoxicillin and bismuth achieved 92.8% cure rates per protocol in a country with a high background rate of resistance. Additional studies are needed to ascertain whether this therapy can be further improved. Until then, it can be recommended as a first-line H. pylori eradication in north of Iran.

The Anti-Helicobacter pylori effects of Limosilactobacillus reuteri strain 2892 isolated from Camel milk in C57BL/6 mice

Helicobacter pylori infection (H. pylori) is associated with chronic gastritis, peptic ulcers, and gastric cancer. The present study provides information on the protective effects of Limosilactobacillus reuteri strain 2892 (L. reuteri 2892) isolated from camel's milk against H. pylori-induced gastritis in the stomach tissue of animal models. Animal assays revealed that L. reuteri 2892 pretreatment significantly downregulated the virulence factor cagA gene expression. It upregulated the expression level of tight junction molecules [zona occludens (ZO-1), claudin-4] and suppressed metalloproteinase (MMP)-2 and MMP-9 expressions. L. reuteri 2892 exhibited immunomodulatory effects on cytokine profile, as it reduced the serum concentrations of pro-inflammatory cytokines interleukin (IL)-6, IL-1β, and INF-γ and increased the anti-inflammatory cytokine, IL-10. In addition, L. reuteri 2892 showed anti-oxidative stress activity by regulating the levels of oxidative stress-associated markers [superoxide dismutase (SOD) and malondialdehyde (MDA)]. Our findings suggest that L. reuteri 2892 attenuates H. pylori-induced gastritis.

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.

Tailored therapy for Helicobacter pylori eradication: A systematic review and meta-analysis

Background: Due to an increase in drug resistance, the eradication rate of H. pylori with empirical therapy has declined. Tailored therapy has been proposed as an alternative to standard empirical treatments. The necessity of personalized eradication therapy remains unclear. The aim of this study was to determine whether tailored therapy is superior to empirical therapy for H. pylori infection. Methods: We searched for eligible randomized controlled trials in the PubMed, Embase (Ovid), Wanfang, and Cochrane Central Register of Controlled Trials databases up to 10 December 2021. A random effects model comparing pooled relative risks (RRs) with 95% confidence intervals (CIs) was applied in the meta-analysis. Results: Twenty-one studies were included in the meta-analysis. In the first-line treatment, tailored therapy was more effective than empirical therapy (RR, 1.14 [95% CI, 1.08-1.21], I2 = 72.2%). In the second-line therapy setting, the results did not reveal significant differences between the two treatments (RR, 1.05 [95% CI, 0.84-1.30], I2 = 80.6%). A similar result was observed in mixed second- and third-line treatments (RR, 1.03 [95% CI, 0.96-1.11], I2 = 0.0%). Regarding adverse events, no significant differences were found between the two treatments (RR, 0.90 [95% CI, 0.80-1.01], I2 = 35.7%). Most of the results were highly heterogeneous. Conclusion: A tailored approach might provide a better eradication rate than empirical methods in first-line treatment. There might be no obvious advantage in second-line or mixed second- and third-line treatments third-line treatment. Due to the high heterogeneity, the results should be interpreted with caution. Further clinical studies are needed and justified.

Nanocluster-mediated photothermia improves eradication efficiency and antibiotic sensitivity of Helicobacter pylori

Background

Helicobacter pylori (H. pylori) eradication plays a crucial role in gastric cancer prevention, but the antimicrobial resistance of H. pylori is obstructing this elimination process. In this study, we developed nanoclusters (NCs) from Zn0.3Fe2.7O4 nanoparticles using a poly(ethylene glycol)-b-poly(ε-caprolactone)-based nanocarrier as an innovative antibiotic-independent H. pylori management.

Results

The nanocluster showed minimal toxicity and maximal biocompatibility. With a low concentration (50 µg/mL) of NCs under a short time period (~ 2 min) of near-infrared (808 nm) irradiation, we kept the culture medium temperature to 41 °C for 20 min with continuous irradiation. The heated NCs exhibited efficient photothermal effects and resulted in an excellent inhibition of H. pylori growth, adhesion and ability to induce vacuolization in eukaryotic cells in in vitro investigation. Transmission electron microscopy showed a dramatic morphologic change after NCs photothermia on H. pylori, including cell wall and membrane rupture, as well as ribosome damage. Besides, levofloxacin and clarithromycin resistance was decreased after photothermal treatment in H. pylori NCTC 11637 and/or clinical strains, however metronidazole resistance was unchanged. We also discovered a significant decrease in the biofilm formation of H. pylori under the NCs-based photothermal application, while efflux pump function was unchanged.

Conclusions

Based on this novel NCs-based photothermal approach, we were able to demonstrate in vitro a significant inhibition of both H. pylori growth and molecular toxicity, and its improvement in antibiotic sensitivity alone with the eradication of H. pylori biofilms previously believed to be tolerant to conventional antibiotics.

Cross-roads for meta-analysis and network meta-analysis of H. pylori therapy

Helicobacter pylori infections are responsible for tremendous morbidity and mortality worldwide, leading to efforts to eradicate the organism. However, the effectiveness of antimicrobial therapy has been undermined by the progressive development of antimicrobial resistance. Treatments and treatment guidelines have been based on traditional pairwise meta-analyses of randomised controlled trials. More recently, network meta-analyses have also been used in an attempt to provide useful information to the clinician regarding which therapies appear best and which to avoid as the least efficacious. However, both forms of meta-analysis have been undermined by the same problems including the poor quality of the clinical trials using unoptimised regimens and incomparable comparisons related to marked geographic and ethnic genotypic and phenotypic heterogeneity. In addition, the comparator regimens often consist of invalid strawman comparisons. New approaches concerning H. pylori treatment and analysis of therapies are needed. H. pylori therapies should be based on antimicrobial stewardship, as in other infectious diseases. This approach requires the use of only optimised therapies proven to be reliably highly effective in the local population (eg, a cure rate of >90%) for both the study and the comparator regimens. Meta-analyses should be restricted to regimens that meet these criteria and must take into account the presence of marked geographical and host genetic and phenotypic heterogeneity. In addition, to provide clinically relevant results, treatment outcomes should focus on, and present, actual cure rates in addition to odd ratios.

Empiric "Three-in-One" Bismuth Quadruple Therapy for Second-Line Helicobacter pylori Eradication: An Intervention Study in Southern Italy

The eradication of Helicobacter pylori (H. pylori) may be difficult due to antibiotic resistance. Indeed, after one failure, a second-line therapy is needed and a bismuth containing quadruple therapy (BQT) with a three-in-one capsule formulation is becoming very popular. Therefore, we aimed to evaluate effectiveness and safety of BQT as a second-line therapy. We recruited consecutive patients with one therapy failure. For ten days patients received the three-in-one BQT Pylera^® therapy, in combination with a proton-pump inhibitor (PPI), decided at the choice of the investigator, at full dose bid. The eradication rate was calculated by intention-to-treat (ITT) and per-protocol (PP)analyses and 95% confidence intervals (CI) were calculated. Seventy-three patients were recruited, 41 females and 32 males (mean age 53.0±13.1 years). Fifty-five patients failed triple therapy with amoxicillin and clarithromycin and the remaining 18 received sequential therapy. Seventy-two patients consumed at least 90% of the capsules, while only one did not complete the therapy due to adverse events (nausea and diarrhea). By ITT analysis, BQT was successful in 62 subjects (eradication rate 84.9%, 95%CI 76.7–93.1%). By PP analysis, the eradication rate was 86.1% (95%CI 78.1–94.1%).Adverse events were observed in 14 subjects (20.5%).In conclusion, our report confirmed that BQT is effective as an empiric second-line regimen.

The efficacy and safety of furazolidone-bismuth quadruple therapy for Helicobacter pylori eradication with or without probiotic supplementation

Aim

In this clinical trial we use furazolidone-bismuth quadruple therapy with or without probiotics for H.pylori eradication.

Background

Increasing rates of eradication failure in H.pylori infection mainly due to antibiotic resistance has led to search for alternative regimens such as using novel antibiotics and/or using probiotic supplementation as conjunctive to the standard eradication regimens.

Methods

This double blind clinical trial was performed in gastrointestinal clinic of Loghman Hakim University Hospital, Tehran, Iran. Patients with a positive pathology test for H.pylori were enrolled to the study and received a 14 day course of furazolidone 100 mg q.i.d, bismuth 240 mg b.i.d, amoxicillin 1000 mg b.i.d, pantoprazole 40 mg b.i.d plus either probiotic (Familact) b.i.d or placebo b.i.d. Adverse effects and adherence to therapy were evaluated at the end of the treatment course. Eradication was established by H.pylori fecal antigen test.

Results

A total of 200 patients entered the study and were randomly assigned to two groups of placebo and probiotic. There was no significant difference regarding age or gender between placebo and probiotic groups. Adherence to therapy was higher than 90% in total and not significantly different between placebo and probiotic groups. Total eradication rate was 80.5% (n=161). Eradication rate was 84% in probiotic group vs 77% in placebo group (P=0.2). Total rate of adverse effects was 30% in probiotic group vs 62% in placebo group. The most common adverse effects were abdominal pain (15% in probiotic group vs 28% in placebo group, P=0.03) followed by diarrhea (5% in probiotic group vs 12% in placebo group, P=0.1).

Conclusion

According to our results, adding probiotic to furazolidone-bismuth quadruple therapy did no increase the eradication rate significantly. However, adverse effects particularly abdominal pain was lower in the probiotic group when compared with placebo.

Second-Line Bismuth-Containing Quadruple Therapy for Helicobacterpylori Infection: A 12-Year Study of Annual Eradication Rates

Background: Bismuth-containing quadruple therapy (BQT) consisting of a proton-pump inhibitor (PPI), bismuth, metronidazole and tetracycline is recommended as a second-line treatment for Helicobacter pylori (H. pylori) infection when PPI-based standard triple therapy (STT) consisting of a PPI, amoxicillin and clarithromycin is unsuccessful. The purpose of this study was to analyze the long-term results of BQT as a second-line therapy to determine its effectiveness. Methods: This study included 643 subjects who failed first-line STT and received 7 or 10–14 days of BQT as a second-line therapy. We retrospectively analyzed the annual H. pylori eradication rates, demographic factors and adverse events. Results: The overall eradication rates by intention-to-treat (ITT) and per-protocol (PP) analyses were 80.7% (519/643) and 93.3% (519/556), respectively. By PP analysis, the eradication rates for 2008–2011, 2012–2015, and 2016–2019 were 93.3%, 91.0%, and 96.4%, respectively (p = 0.145). There were no significant differences between the 7-day group and the 10–14-day group in both the ITT (79.7% vs. 86.0%, p = 0.148) and the PP analyses (92.7% vs. 96.6%, p = 0.187). A multivariate analysis showed that current smoking was associated with eradication failure. Eighty-nine subjects (16.0%) suffered adverse events, mainly gastrointestinal symptoms, but only six cases were severe. Conclusions: BQT as a second-line therapy is an effective treatment for H. pylori. Treatment for 10–14 days showed a higher eradication rate compared with a 7-day regimen, but not significantly.

Rheumatic Heart Disease and Its Association with H. pylori Infection

Acute rheumatic fever (ARF) triggered by Group A streptococcus bacterium due to post-infectious and non-supportive pharyngeal infection. Depending on certain conditions, such as genetic predisposition to the disease, the prevalence of various cases of rheumatism and socioeconomic status in different regions, ARF can have different clinical manifestations. The disease typically manifested by one or more acute episodes, whereas 30-50% of all repeated ARF status can result in chronic rheumatic heart disease (RHD) with gradual and irreversible heart valve damage and also have been found to be correlated with a raised risk of myocardial infarction (MI), cardiovascular disease (CVD) and dyslipidemia. The RHD is the only long-term consequence of ARF and the most serious. The development to chronic RHD is determined by many factors, most notably the frequent episodes of rheumatic fever (RF). The RHD is known socially and economically as being the most frequent heart disease in vulnerable populations. H.pylori infection has been proposed to be involved RHD greater than that of the normal healthy people. H.pylori can be considered as one of the probable risk factor for RHD.It was concluded that patients with H. Pylori should be advised to follow up in cardiology clinics to avoid any complications.

Phenotypic and Genotypic Antibiotic Resistance Patterns in Helicobacter pylori Strains From Ethnically Diverse Population in México

Helicobacter pylori strains carry a range of mutations in genes that confer antimicrobial resistance and restrict the available options to treat the infection. Latin America is a region that conserve a large number of indigenous communities relatively isolated that practice a traditional medicine without consumption of drugs. We hypothesized that rates of antibiotic resistance are lower in these communities. Recent progress in whole-genome sequencing has allowed the study of drug susceptibility by searching for the known mutations associated with antibiotic resistance. The aim of this work was to study trends of antibiotic resistance over a 20-year period in Mexican H. pylori strains and to compare susceptibility between strains from Mexican mestizos and from indigenous population; we also aimed to learn the prevalence of mutational patterns in genes gyrA, gyrB, rdxA, frxA, rpsU, omp11, dppA, and 23S rRNA and its association with phenotypic tests. Resistance to clarithromycin, metronidazole, amoxicillin and levofloxacin was determined in167 H. pylori isolates by E-test, and the occurrence of mutational patterns in specific genes was determined by whole genome sequencing (WGS). The trend of resistance over 20 years in mestizo isolates showed significant resistant increase for clarithromycin and levofloxacin to frequencies that banned its clinical use. Resistance in H. pylori isolates of native communities was lower for all antibiotics tested. Phenotypic resistance showed good to moderate correlation with genotypic tests. Genetic methods for characterizing antibiotic resistance require further validation in each population.

Two-weeks repeated-dose oral toxicity study of Pediococcus acidilactici J9 in a mice model

BACKGROUND

Helicobacter pylori (H. pylori) is an important pathogen that causes chronic gastritis and peptic ulcer, and is related to the development of gastric carcinoma. Several chemicals, including antibiotics, have been used to eradicate H.pylori. However, more studies are yet requred to accomplish a sufficient therapy. Pediococcus acidilactici (P. acidilactici) J9 were studied for inhibition of binding of H.pylori binding to human gastric cell lines. This study was performed in order to investigate the repeated-dose toxicity of P. acidilactici J9 in male and female mice.

RESULTS

C57BL/6 male and female Mus musculus were divided into four groups (n = 10 in each group). P. acidilactici J9 was administered daily by oral injection of vehicle control at dosage levels to a low-dose group (500 mg/kg/day), middle-dose group (1000 mg/kg/day), and high-dose group (2000 mg/kg/day) for 2 weeks. After 14 days of exposure, the blood biochemistry and hematology were investigated, along with a histopathology exam. There were no bacterial-related deaths or abnormal clinical signs in either gender of mouse. The data was observed during the period in terms of body weight, food intake, and water consumption. Also, no alterations in organ weights upon administration of P. acidilactici J9 alone were observed. The adhesion and growth of H. pylori were inhibited by a 24 h treatment of H. pylori and P. acidilactici J9 on adenocarcinoma gastric (AGS) cells, which are gastric cancer cells. Compared to the control group (AGS cell and H. pylori), the number of H. pylori analyzed by FACS significantly (p < 0.01) decreased after incubation of AGS cell with P. acidilactici J9 for 24 h.

CONCLUSIONS

These results suggest that the oral application of P. acidilactici J9, up to a dosage level of 2000 mg/kg/day, causes no adverse effects in both male and female mice. P. acidilactici J9 inhibits the adhesion of H.pylori to AGS cancer cells. When used as probiotics, P. acidilactici J9 may help decrease the occurrence of gastritis and reduce the risk of H.pylori infection with promising safety issues.

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.

Age and gender-specific antibiotic resistance patterns among Bangladeshi patients with urinary tract infection caused by Escherichia coli

Background

In Bangladesh, treatment for urinary tract infection has become increasingly difficult due to antibiotic resistance. In addition, the prescription of age and gender-specific drugs is still far from being practiced in Bangladesh. We are examining trends of antibiotic resistance per age and gender in patients with urinary tract infection (UTI) caused by the most frequent agent, Escherichia coli.

Methods

We determined the resistance of 1663 E. coli isolates obtained from urine cultures. A sensitivity study using the Kirby-Bauer method was carried out to identify the antibiotic resistance trends.

Results

Imipenem with 1.9% resistance of all isolates found to be the lowest percentage of resistance. Meropenem (2.8%), amikacin (2.8%), colistin (2.9%), and nitrofurantoin (15.8%) showed low resistance percentages. The sensitivity analysis suggests that age and gender (area under curve = 0.67) should be taken into consideration to prescribe amikacin. The increasing odds ratios (OR) by age groups suggest that amikacin is a less effective agent for older patients with UTIs. Moreover, nitrofurantoin (OR = 1.45, 95% confidence interval (CI) = 1.07–1.95) and colistin (OR = 2.09, CI = 1.13–3.76) were less effective against isolates obtained from males compared to isolates obtained from females. Meropenem was effective against bacteria obtained from all age groups and genders. On the other hand, efficacy of imipenem was lower in isolates obtained from adults older than 40 years (OR: 0.44 for < = 18 years, OR = 0.47 for 19–40 years, OR = 0.86 for 41–60 years; reference: > = 61 years).

Conclusion

In Bangladesh, meropenem, imipenem, amikacin, colistin, and nitrofurantoin are suitable therapeutic alternatives against urinary tract pathogens. Among the oral agents, amikacin, colistin, and nitrofurantoin should be prescribed, taking consideration of age and gender. These results will assist physicians in prescribing effective primary care antibiotics for UTI patients and encouraging the implementation of health policies for a safe prescription of antibiotics.

The Puzzle of Coccoid Forms of Helicobacter pylori: Beyond Basic Science

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.

Mutations in the Antibiotic Target Genes Related to Clarithromycin, Metronidazole and Levofloxacin Resistance in Helicobacter pylori Strains from Children in China

Purpose

This study aimed to characterize common mutations of antibiotic-resistant gene of clarithromycin, metronidazole and levofloxacin in Helicobacter pylori (H. pylori) and determine their association with antibiotic resistance of H. pylori for providing a strategy for eradication therapy of H. pylori infection in children.

Patients and Methods

The antibiotic resistance to clarithromycin, metronidazole and levofloxacin for H. pylori strains isolated from children was determined by E-test. The mutation of domain V of 23S rRNA, rdxA and frxA genes, gyrA and gyrB genes was performed by PCR-based sequencing of DNA fragments.

Results

Out of the 79 H. pylori strains examined, 66 (83.5%) were resistant to at least one of the tested antibiotics and 13 (16.5%) were fully sensitive. A total of 29 (36.7%) strains were resistant to clarithromycin. Analysis of the 23S rRNA gene showed that most mutations occurred at the A2143G and T2182C sites, showing a frequency of 82.8% (24/29) and 89.7% (26/29) respectively. In the 11 sensitive strains to clarithromycin, the frequency of A2143G mutation was only 45.5%, which was significantly lower than that in resistant strains (P<0.05). There were 54 strains (68.4%) resistant to metronidazole, with most mutations occurring at G47A and T184G in the rdxA gene. T184G mutation was recognized in metronidazole-sensitive strains, but no G47A mutation was identified. Twelve strains (15.2%) were resistant to levofloxacin. Position 91 mutation of the gyrA gene occurred only in resistant strains, whereas position 87 mutations were detected in both sensitive and resistant strains to levofloxacin.

Conclusion

In H. pylori resistant strains isolated from children in China, most mutations occurred at A2143G of the 23S rRNA gene for clarithromycin; G47A mutation of rdxA gene for metronidazole; and at 91 mutation of gyrA gene for levofloxacin. It is suggested that susceptibility testing together with screening the mutation of antimicrobial-resistant gene prior to treatment is important for the eradication of H. pylori in children.

Treatment of Helicobacter pylori with nitazoxanide-containing regimens: a systematic review

Background: Helicobacter pylori is one of the most common chronic infections and is a leading cause of gastric cancer. There are currently several short-course treatment options available for the treatment of H. pylori. However, there has been a significant increase in global resistance patterns for H. pylori and there is a need for alternative treatment regimens. Nitazoxanide (NTZ) is an anti-protozoal agent that has been evaluated within several studies for the treatment of H. pylori. The objective of this review is to evaluate the efficacy and safety of NTZ-based treatments for a H. pylori infection.Methods: Pubmed (1946-August 2019) and Embase (1947-August 2019) were queried using the following search terms: Helicobacter, Helicobacter infection, Helicobacter pylori, nitazoxanide, tizoxanide, thiazoles, thiazole derivative and NTZ. Appropriate studies were evaluated with varying treatment regimens and cure rates.Results: Ten studies that utilized a NTZ-based treatment for H. pylori were identified from the literature search. Eight of the ten studies demonstrated a cure rate of greater than 80% in at least one NTZ-based treatment arm. Gastrointestinal side effects were the most commonly reported adverse drug reaction in the studies.Conclusions: Nitazoxanide-based treatments appear to be an effective treatment for H. pylori. While the ideal NTZ combination therapy is uncertain, a combination with a proton-pump inhibitor and one to two antibiotics has demonstrated the highest rates of H. pylori eradication. Nitazoxanide-based treatments are well-tolerated and minimal discontinuation due to side effects were reported in the studies.

High Prevalence of Antibiotic Resistance in Iranian Helicobacter pylori Isolates: Importance of Functional and Mutational Analysis of Resistance Genes and Virulence Genotyping

The high prevalence of antibiotic resistance in Helicobacter pylori has become a great challenge in Iran. The genetic mutations that contribute to the resistance have yet to be precisely identified. This study aimed to investigate the prevalence of antibiotic resistance and virulence markers in Iranian H. pylori isolates and to analyze if there is any association between resistance and genotype. Antibiotic susceptibility patterns of 68 H. pylori isolates were investigated against metronidazole, clarithromycin, amoxicillin, rifampicin, ciprofloxacin, levofloxacin, and tetracycline by the agar dilution method. The frxA, rdxA, gyrA, gyrB, and 23S rRNA genes of the isolates were sequenced. The virulence genotypes were also determined using PCR. Metronidazole resistance was present in 82.4% of the isolates, followed by clarithromycin (33.8%), ciprofloxacin (33.8%), rifampicin (32.4%), amoxicillin (30.9%), levofloxacin (27.9%), and tetracycline (4.4%). Overall, 75% of the isolates were resistant to at least two antibiotics tested and considered as a multidrug resistance (MDR) phenotype. Most of the metronidazole-resistant isolates carried frameshift mutations in both frxA and rdxA genes, and premature termination occurred in positions Q5Stop and Q50Stop, respectively. Amino acid substitutions M191I, G208E, and V199A were predominantly found in gyrA gene of fluoroquinolone-resistant isolates. A2143G and C2195T mutations of 23S rRNA were found in four clarithromycin-resistant isolates. Interestingly, significant associations were found between resistance to metronidazole (MNZ) and cagA-, sabA-, and dupA-positive genotypes, with p = 0.0002, p = 0.0001, and p = 0.0001, respectively. Furthermore, a significant association was found between oipA “on” status and resistance to amoxicillin (AMX) (p = 0.02). The prevalence of H. pylori antibiotic resistance is high in our region, particularly that of metronidazole, clarithromycin, ciprofloxacin, and MDR. Simultaneous screening of virulence and resistance genotypes can help clinicians to choose the appropriate therapeutic regime against H. pylori infection.

Pathogenesis and clinical management of Helicobacter pylori gastric infection

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. However, its prevalence varies among different geographic areas, and is influenced by several factors. The infection can be acquired by means of oral-oral or fecal-oral transmission, and the pathogen possesses various mechanisms that improve its capacity of mobility, adherence and manipulation of the gastric microenvironment, making possible the colonization of an organ with a highly acidic lumen. In addition, H. pylori presents a large variety of virulence factors that improve its pathogenicity, of which we highlight cytotoxin associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and gamma-glutamyl transpeptidase. The host immune system, mainly by means of a Th1-polarized response, also plays a crucial role in the infection course. Although most H. pylori-positive individuals remain asymptomatic, the infection predisposes the development of various clinical conditions as peptic ulcers, gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. Invasive and non-invasive diagnostic methods, each of them with their related advantages and limitations, have been applied in H. pylori detection. Moreover, bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection, and new therapy alternatives are being tested to improve H. pylori eradication. Last but not least, the development of effective vaccines against H. pylori infection have been the aim of several research studies.

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 of current diagnostic methods and advances in Helicobacter pylori diagnostics in the era of next generation sequencing

Helicobacter pylori (H. pylori) infection is highly prevalent in the human population and may lead to severe gastrointestinal pathology including gastric and duodenal ulcers, mucosa associated tissue lymphoma and gastric adenocarcinoma. In recent years, an alarming increase in antimicrobial resistance and subsequently failing empiric H. pylori eradication therapies have been noted worldwide, also in many European countries. Therefore, rapid and accurate determination of H. pylori’s antibiotic susceptibility prior to the administration of eradication regimens becomes ever more important. Traditionally, detection of H. pylori and its antimicrobial resistance is done by culture and phenotypic drug susceptibility testing that are cumbersome with a long turn-around-time. Recent advances in diagnostics provide new tools, like real-time polymerase chain reaction (PCR) and line probe assays, to diagnose H. pylori infection and antimicrobial resistance to certain antibiotics, directly from clinical specimens. Moreover, high-throughput whole genome sequencing technologies allow the rapid analysis of the pathogen’s genome, thereby allowing identification of resistance mutations and associated antibiotic resistance. In the first part of this review, we will give an overview on currently available diagnostic methods for detection of H. pylori and its drug resistance and their implementation in H. pylori management. The second part of the review focusses on the use of next generation sequencing technology in H. pylori research. To this end, we conducted a literature search for original research articles in English using the terms “Helicobacter”, “transcriptomic”, “transcriptome”, “next generation sequencing” and “whole genome sequencing”. This review is aimed to bridge the gap between current diagnostic practice (histology, rapid urease test, H. pylori culture, PCR and line probe assays) and new sequencing technologies and their potential implementation in diagnostic laboratory settings in order to complement the currently recommended H. pylori management guidelines and subsequently improve public health.

Vonoprazan and Helicobacter pylori Treatment: A Lesson From Japan or a Limited Geographic Phenomenon?

Within a short time after the discovery of Helicobacter pylori, its critical role in many gastroduodenal disorders became evident. Many in vitro and in vivo data have proven that infection should be treated in order to avoid lasting colonization which may lead to problematic gastroduodenal diseases. Probiotics, preventive and therapeutic vaccines and antibiotic therapy are the main options proposed to cure these disorders. 25 years ago, triple therapy including a traditional proton pump inhibitor (PPI) and two antibiotics (amoxicillin and clarithromycin or metronidazole) was defined as the best therapy formulation for the H. pylori infection. With the strongly decreased effectiveness of this scheme, many empirical therapeutic regimens have been developed. However, the prevalence of resistance is increasing worldwide and reveals important geographic differences and even the most recent and effective regimens show some critical points. Therefore, efficacy of vonoprazan-based therapy in regions with low rate of clarithromycin resistance may be limited. In this review, we attempt to open a new window to overcome the problem of antibiotic resistance to H. pylori. In fact, we focused our attention on the possibility that conventional PPI may be replaced by vonoprazan, thus giving rise to the beginning of a new era characterized by an improved therapeutic option for H. pylori infection. Therefore, we hypothesize that switching to vonoprazan as a novel acid blocker for H. pylori treatment might allow an unexpected reassessment of the triple therapy, at least in regions with low rate of clarithromycin resistance. Nevertheless, this optimistic view of the problem could be disproved by the possible failure of vonoprazan based therapeutic regimens outside of Japan in geographic areas characterized by different rates of antibiotic resistances.

Molecular Patterns of Resistance Among Helicobacter pylori Strains in South-Western Poland

Treatment failure of Helicobacter pylori infection is caused mainly by progressive antibiotic resistance among H. pylori strains. In Poland, the prevalence of H. pylori strains resistant to metronidazole is higher than in other developed countries, reaching almost 50%, and resistance to clarithromycin is as high as 30% and is still increasing, contributing to the failure of first-line therapy in approximately 70% of patients. Moreover, the introduction of levofloxacin to eradication therapy of H. pylori infection quickly led to the emergence of resistant strains. Therefore, a necessary approach in microbiological diagnostics of H. pylori infection should be determination of susceptibility of H. pylori strains before the eradication treatment.

Aim: In this study was to evaluate the molecular mechanisms of resistance among 170 H. pylori strains to clarithromycin, involving mutations in the 23S rRNA gene (A2143G, A2142G, A2143G) and to levofloxacin, involving mutations of gyrA and gyrB. Analysis was performed by using polymerase chain reaction and classical sequencing of DNA fragments.

Results: Among examined strains, 26% were fully sensitive and 74% were resistant to at least one of the tested antibiotics. The overall resistance rate to metronidazole was as high as 56%, whereas to clarithromycin 46%, respectively. Resistance to LEV occurred among 6% of strains. All tested strains were susceptible to AMC and TET. The A2143G point mutation was found in 72% of clarithromycin-resistant strains. The most common mutation, present in 40% of H. pylori strains resistant to levofloxacin, was a change at position 91 of gyrA.

Conclusion: The increasing number of point mutations in the 23S rRNA gene leads to an increase in the rates of antimicrobial resistance. Presence of the GCG allele at position 122 of the gyrA gene may cause an eightfold increase in risk of development of resistance to levofloxacin.

A GWAS on Helicobacter pylori strains points to genetic variants associated with gastric cancer risk

Background

Helicobacter pylori are stomach-dwelling bacteria that are present in about 50% of the global population. Infection is asymptomatic in most cases, but it has been associated with gastritis, gastric ulcers and gastric cancer. Epidemiological evidence shows that progression to cancer depends upon the host and pathogen factors, but questions remain about why cancer phenotypes develop in a minority of infected people. Here, we use comparative genomics approaches to understand how genetic variation amongst bacterial strains influences disease progression.

Results

We performed a genome-wide association study (GWAS) on 173 H. pylori isolates from the European population (hpEurope) with known disease aetiology, including 49 from individuals with gastric cancer. We identified SNPs and genes that differed in frequency between isolates from patients with gastric cancer and those with gastritis. The gastric cancer phenotype was associated with the presence of babA and genes in the cag pathogenicity island, one of the major virulence determinants of H. pylori, as well as non-synonymous variations in several less well-studied genes. We devised a simple risk score based on the risk level of associated elements present, which has the potential to identify strains that are likely to cause cancer but will require refinement and validation.

Conclusion

There are a number of challenges to applying GWAS to bacterial infections, including the difficulty of obtaining matched controls, multiple strain colonization and the possibility that causative strains may not be present when disease is detected. Our results demonstrate that bacterial factors have a sufficiently strong influence on disease progression that even a small-scale GWAS can identify them. Therefore, H. pylori GWAS can elucidate mechanistic pathways to disease and guide clinical treatment options, including for asymptomatic carriers.

Electronic supplementary material

The online version of this article (10.1186/s12915-018-0550-3) contains supplementary material, which is available to authorized users.

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

AIM

To assess the diagnostic accuracy of a new fecal test for detecting Helicobacter pylori (H. pylori), using¹³C-urea breath test as the reference standard, and explore bacterial antibiotic resistance.

METHODS

We conducted a prospective two-center diagnostic test accuracy study. We enrolled consecutive people≥ 18 years without previous diagnosis of H. pylori infection, referred for dyspepsia between February and October 2017. At enrollment, all participants underwent ¹³C-urea breath test. Participants aged over 50 years were scheduled to undergo upper endoscopy with histology. Participants collected stool samples 1-3 d after enrollment for a new fecal investigation (THD fecal test). The detection of bacterial 23S rRNA subunit gene indicated H. pylori infection. We also used the index diagnostic test to examine mutations conferring resistance to clarithromycin and levofloxacin. Independent investigators analyzed index test and reference test standard results blinded to the other test findings. We estimated sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, diagnostic accuracy, positive and negative likelihood ratio (LR), together with 95% confidence intervals (CI).

RESULTS

We enrolled 294 consecutive participants (age: Median 37.0 years, IQR: 29.0-46.0 years; men: 39.8%). Ninety-five (32.3%) participants had a positive¹³C-urea breath test. Twenty-three (7.8%) participants underwent upper endoscopy with histology, with a full concordance between ¹³C-urea breath test and histology in detecting H. pylori infection. Four (1.4%) out of the 294 participants withdrew from the study after the enrollment visit and did not undergo THD fecal testing. In the 290 participants who completed the study, the THD fecal test sensitivity was 90.2% (CI: 84.2%-96.3%), specificity 98.5% (CI:96.8%-100%), PPV 96.5% (CI: 92.6%-100%), NPV 95.6% (CI: 92.8%-98.4%), accuracy 95.9% (CI: 93.6%-98.2%), positive LR 59.5(CI: 19.3-183.4), negative LR 0.10 (CI: 0.05-0.18). Out of 83 infected participants identified with the THD fecal test, 34 (41.0%) had bacterial genotypic changes consistent with antibiotic-resistant H. pylori infection. Of these, 27 (32.5%) had bacterial strains resistant to clarithromycin, 3 (3.6%) to levofloxacin, and 4 (4.8%) to both antibiotics.

CONCLUSION

The THD fecal test has high performance for the non-invasive diagnosis of H. pylori infection while additionally enabling the assessment of bacterial antibiotic resistances.

The diagnosis and management of H. pylori infection in Singapore

Helicobacter pylori (H. pylori) is an infection that has a role in causing dyspepsia and complications such as peptic ulcer disease and gastric malignancies. In the primary care setting, one can adopt a stepwise approach with the 'test-and-treat' strategy to manage H. pylori-associated dyspepsia in young patients without alarm symptoms. Empiric first-line therapies should be for a two-week duration; options include clarithromycin-containing triple therapy alone or with the addition of bismuth, concomitant therapy and bismuth quadruple therapy. Post-treatment carbon urea breath test must be performed at least four weeks after the end of treatment to confirm the cure. Options for empiric second-line treatment include bismuth quadruple therapy and levofloxacin-containing triple therapy. Patients with persistent or alarm symptoms should be referred for further evaluation. Patients with persistent infection should be referred for gastroscopy so that gastric biopsies can be obtained for H. pylori culture and antibiotic susceptibility testing.

In Vitro Activity of Diphenyleneiodonium toward Multidrug-Resistant Helicobacter pylori Strains

Background/Aims

The increased resistance of Helicobacter pylori to antibiotics has increased the need to develop new treatments for this bacterium. The aim of our study was to identify new drugs with anti-H. pylori activity.

Methods

We screened a small molecule library—the library of pharmacologically active compounds (LOPAC), which includes 1,280 pharmacologically active compounds—to identify inhibitors of H. pylori growth. The minimal inhibitory concentrations (MICs) of antibiotics against multidrug-resistant H. pylori strains were determined using the agar dilution method.

Results

We identified diphenyleneiodonium (DPI) as a novel anti-H. pylori agent. The MIC values for DPI were <0.03 μg/mL against all tested H. pylori strains. DPI also exhibited strong antibacterial activity against common gram-negative and gram-positive pathogenic bacteria.

Conclusions

DPI may be a candidate anti-H. pylori drug for future development.

Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis

Despite decades of effort, Helicobacter pylori infections remain difficult to treat. Over half of the world's population is infected by H. pylori, which is a major cause of duodenal and gastric ulcers as well as gastric cancer. During chronic infection, H. pylori localizes within the gastric mucosal layer, including deep within invaginations called glands; thanks to its impressive ability to survive despite the harsh acidic environment, it can persist for the host's lifetime. This ability to survive and persist in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation has recently been suggested to play a role in colonization. Biofilms are surface-associated communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances. Biofilms pose a substantial health risk and are key contributors to many chronic and recurrent infections. This link between biofilm-associated bacteria and chronic infections likely results from an increased tolerance to conventional antibiotic treatments as well as immune system action. The role of this biofilm mode in antimicrobial treatment failure and H. pylori survival has yet to be determined. Furthermore, relatively little is known about the H. pylori biofilm structure or the genes associated with this mode of growth. In this review, therefore, we aim to highlight recent findings concerning H. pylori biofilms and the molecular mechanism of their formation. Additionally, we discuss the potential roles of biofilms in the failure of antibiotic treatment and in infection recurrence.

Current Status of the Third-Line Helicobacter pylori Eradication

Antibiotic resistance is growing worldwide, and patients who have failed consecutive 1st- and 2nd-line H. pylori eradication regimens are increasing. Therefore, the role of the bacterial culture with antibiotic susceptibility testing and molecular susceptibility testing is important for avoiding the use of ineffective antibiotics. However, antibiotic susceptibility testing-guided treatment does not necessarily guarantee successful eradication, and there have been mixed results for the effectiveness of a 3rd-line rescue therapy. Therefore, providing patients with pretreatment medication instructions and education is important. It is also crucial to determine the reason of the eradication failure, including host-related factors (poor compliance to eradication regimen, smoking, and cytochrome P450 2C19 genetic polymorphism) or treatment-related factors (inadequate dosage or duration of therapy and gastric acidity), as such factors can be modified for a tailored therapy. Although the indications for H. pylori eradication have widened, patients at a high risk of gastric cancer can gain definitive benefits with a 3rd-line or even 4th-line therapy.

Flagellin glycosylation with pseudaminic acid in Campylobacter and Helicobacter: prospects for development of novel therapeutics

Many pathogenic bacteria require flagella-mediated motility to colonise and persist in their hosts. Helicobacter pylori and Campylobacter jejuni are flagellated epsilonproteobacteria associated with several human pathologies, including gastritis, acute diarrhea, gastric carcinoma and neurological disorders. In both species, glycosylation of flagellin with an unusual sugar pseudaminic acid (Pse) plays a crucial role in the biosynthesis of functional flagella, and thereby in bacterial motility and pathogenesis. Pse is found only in pathogenic bacteria. Its biosynthesis via six consecutive enzymatic steps has been extensively studied in H. pylori and C. jejuni. This review highlights the importance of flagella glycosylation and details structural insights into the enzymes in the Pse pathway obtained via a combination of biochemical, crystallographic, and mutagenesis studies of the enzyme-substrate and -inhibitor complexes. It is anticipated that understanding the underlying structural and molecular basis of the catalytic mechanisms of the Pse-synthesising enzymes will pave the way for the development of novel antimicrobials.

Probiotic monotherapy and Helicobacter pylori eradication: A systematic review with pooled-data analysis

AIM

To define probiotic monotherapy effect on Helicobacter pylori (H. pylori) status by performing a systematic review.

METHODS

Methods of analysis and inclusion criteria were based on PRISMA recommendations. Relevant publications were identified by searching PubMed, MEDLINE, Science Direct, and EMBASE. The end-point was to estimate eradication rate and urea breath test delta value before and after probiotic monotherapy across all studies and, overall, with a pooled data analysis. Adverse events of probiotic therapy were evaluated. The data were expressed as proportions/percentages, and 95%CIs were calculated. For continuous variables, we evaluated the weighted mean difference. Odd ratios (ORs) were calculated according to the Peto method for the comparison of eradication rates between probiotics and placebo.

RESULTS

Eleven studies were selected. Probiotics eradicated H. pylori in 50 out of 403 cases. The mean weighted eradication rate was 14% (95%CI: 2%-25%, P = 0.02). Lactobacilli eradicated the bacterium in 30 out of 235 patients, with a mean weighted rate of 16% (95%CI: 1%-31%). Saccharomyces boulardii achieved eradication in 6 out of 63 patients, with a pooled eradication rate of 12% (95%CI: 0%-29%). Multistrain combinations were effective in 14 out of 105 patients, with a pooled eradication rate of 14% (95%CI: 0%-43%). In the comparison of probiotics vs placebo, we found an OR of 7.91 in favor of probiotics (95%CI: 2.97-21.05, P < 0.001). Probiotics induced a mean reduction in delta values higher than placebo (8.61% with a 95%CI: 5.88-11.34, vs 0.19% for placebo, P < 0.001). Finally, no significant difference in adverse events was found between probiotics and placebo (OR = 1, 95%CI: 0.06-18.08).

CONCLUSION

Probiotics alone show a minimal effect on H. pylori clearance, thus suggesting a likely direct role.

Limited effectiveness with a 10-day bismuth-containing quadruple therapy (Pylera® ) in third-line recue treatment for Helicobacter pylori infection. A real-life multicenter study

BACKGROUND

Helicobacter pylori antibiotic resistance is an increasing problem worldwide. Pylera^® may be an option as salvage therapy.

AIM

To assess the effectiveness, safety, and tolerance of Pylera^® as a third-line in clinical practice.

MATERIALS AND METHODS

This was a multicenter, observational, prospective database study in four Spanish hospitals. Consecutive H. pylori-infected individuals treated with Pylera^® and a proton-pump inhibitor (PPI) were invited to participate if they had failed to respond to PPI-clarithromycin-amoxicillin as first-line and to levofloxacin-amoxicillin-PPI as second-line therapy. Eradication was tested 4-8 weeks after Pylera^® using a C¹³ -urea breath test. Treatment-related adverse effects (TRAEs) were assessed through a questionnaire and by reviewing databases. A questionnaire on patient satisfaction was completed in the last visit.

RESULTS

Of 103 subjects fulfilling the selection criteria, 101 were included in the intention-to-treat (ITT) analysis and 97 in the per-protocol (PP) analysis. A 10 day course was prescribed in all patients. Esomeprazole 40 mg b.i.d. was the most used PPI regimen (ITT=94.1%). Ninety-seven individuals (ITT=96.04%) completed more than 90% of the treatment. Overall eradication rates were ITT=80.2% (95% confidence interval [CI]: 72.3%-88.1%) and PP=84.4% (95% CI: 76.8%-91.8%). One or more TRAEs were experienced by 67.3% (95% CI: 57.7%-75.7%), all mild or moderate. TRAEs and the number of pills were the main complaints.

CONCLUSION

In an area of high antibiotic resistance to H. pylori, 10-day Pylera^® plus double-dose PPI emerged as an alternative as third-line therapy, although not achieving optimal eradication rates. TRAEs were common but were neither severe nor did they condition compliance.

Noninvasive molecular analysis of Helicobacter pylori: Is it time for tailored first-line therapy?

The main problem of Helicobacter pylori (H. pylori) infection management is linked to antibiotic resistances. This phenomenon has grown in the last decade, inducing a dramatic decline in conventional regimen effectiveness. The causes of resistance are point mutations in bacterial DNA, which interfere with antibiotic mechanism of action, especially clarithromycin and levofloxacin. Therefore, international guidelines have recently discouraged their use in areas with a relevant resistance percentage, suggesting first-line schedules with expected high eradication rates, i.e., bismuth containing or non-bismuth quadruple therapies. These regimens require the daily assumption of a large number of tablets. Consequently, a complete adherence is expected only in subjects who may be motivated by the presence of major disorders. However, an incomplete adherence to antibiotic therapies may lead to resistance onset, since sub-inhibitory concentrations could stimulate the selection of resistant mutants. Of note, a recent meta-analysis suggests that susceptibility tests may be more useful for the choice of first than second-line or rescue treatment. Additionally, susceptibility guided therapy has been demonstrated to be highly effective and superior to empiric treatments by both meta-analyses and recent clinical studies. Conventional susceptibility test is represented by culture and antibiogram. However, the method is not available everywhere mainly for methodology-related factors and fails to detect hetero-resistances. Polymerase chain reaction (PCR)-based, culture-free techniques on gastric biopsy samples are accurate in finding even minimal traces of genotypic resistant strains and hetero-resistant status by the identification of specific point mutations. The need for an invasive endoscopic procedure has been the most important limit to their spread. A further step has, moreover, been the detection of point mutations in bacterial DNA fecal samples. Few studies on clarithromycin susceptibility have shown an overall high sensitivity and specificity when compared with culture or PCR on gastric biopsies. On these bases, two commercial tests are now available although they have shown some controversial findings. A novel PCR method showed a full concordance between tissue and stool results in a preliminary experience. In conclusion, despite poor validation, there is increasing evidence of a potential availability of noninvasive investigations able to detect H. pylori resistances to antibiotics. These kinds of analysis are currently at a very early phase of development and caution should be paid about their clinical application. Only further studies aimed to evaluate their sensitivity and specificity will afford novel data for solid considerations. Nevertheless, noninvasive molecular tests may improve patient compliance, time/cost of infection management and therapeutic outcome. Moreover, the potential risk of a future increase of resistance to quadruple regimens as a consequence of their use on large scale and incomplete patient adherence could be avoided.

Clarithromycin-Based Triple Therapy is Still Useful as an Initial Treatment for Helicobacter pylori Infection in the Dominican Republic

AbstractHelicobacter pylori antibiotic susceptibility in the Dominican Republic has not been monitored. We assessed H. pylori antibiotic susceptibility in the Dominican Republic, and analyzed H. pylori mutations associated with antibiotic resistance. We recruited 158 dyspeptic patients in Santo Domingo and used agar dilution to test susceptibility to five antibiotics. Polymerase chain reaction-based sequencing was used to assess gyrA, gyrB, rdxA, frxA, and 23S rRNA mutations; next-generation sequencing was used to identify other metronidazole resistance-associated genes. Among 64 H. pylori strains isolated, we identified two (3.1%), one (1.6%), and no strains with clarithromycin, amoxicillin, and tetracycline resistance, respectively. Moreover, high frequency of metronidazole resistance (53/64, 82.8%) was observed, whereas levofloxacin resistance is emerging (23/64, 35.9%). We identified many rdxA and frxA mutations in metronidazole-resistant strains, but no synergistic effect was apparent. We revealed novel mutations in dppA, dppB, fdxA, and fdxB, irrespective of rdxA and frxA mutations. Novel mutations at Ser-14 of trx1 and Arg-221 of dapF were associated with different levels of metronidazole resistance. Most levofloxacin-resistant strains had a substitution at Asn-87 of gyrA, including the strain with the highest levofloxacin resistance, whereas only three substitutions were found at Ser-479 of gyrB with no synergistic effect. Besides the 23S rRNA A2142G mutation, we observed another mutation at T1958G in both clarithromycin-resistant strains. We confirmed high metronidazole and levofloxacin resistance associated with genetic mutations in the Dominican Republic. However, prevalence of clarithromycin resistance was low, suggesting that standard clarithromycin-based triple therapy remains useful as initial treatment of H. pylori infection.

[Ten-day Sequential Therapy versus Bismuth Based Quadruple Therapy as Second Line Treatment for Helicobacter pylori Infection]

BACKGROUND/AIMS

Ten-day sequential therapy has been evaluated as the first line therapy for Helicobacter pylori eradication but studies on sequential therapy as a second line therapy is lacking. The aim of this study was to compare the efficacy of 10-day sequential therapy and quadruple therapy as second line treatment for H. pylori eradication after failure of standard triple therapy.

METHODS

Patients who did not respond to standard triple therapy for H. pylori eradication were assigned to either 10-day sequential or bismuth based quadruple therapy as second line treatment from January 2009 to December 2014 at Yeungnam University Medical Center. Post treatment H. pylori status was determined by rapid urease test, giemsa staining, or (13)C-urea breath test. Eradication rate and side effects of both therapies were compared.

RESULTS

A total of 158 H. pylori infected patients were included and 70 patients were treated by bismuth based quadruple therapy and 88 patients by 10-day sequential therapy. Age and sex were not significantly different between the two groups. Eradication rate was 84.3% (59/70) in quadruple group and 56.8% (50/88) in sequential group. Side effects occurred significantly higher in quadruple group than sequential group (27.1% vs. 11.4%, p=0.011).

CONCLUSIONS

For second line H. pylori eradication after failure of standard triple therapy, bismuth based quadruple therapy showed significantly higher H. pylori eradication rate than 10-day sequential therapy. Further prospective studies are needed to evaluate the efficacy of 10-day sequential therapy as a second line H. pylori eradication treatment.

Lymphocytic duodenitis or microscopic enteritis and gluten-related conditions: what needs to be explored?

Microscopic enteritis (ME) is characterized by abnormal infiltration of intraepithelial lymphocytes in intestinal mucosa. It was described as duodenal lymphocytosis or lymphocytic duodenitis until the dedicated Consensus Conference of 2015. ME represents a common feature of several gluten-mediated and non-gluten related diseases; therefore, it is an umbrella term embracing several conditions. The most frequent causes of ME are gluten-related disorders (celiac disease, non-celiac gluten sensitivity, wheat allergy), Helicobacter pylori infection and drug-related damages. Less frequently, ME may be secondary to inflammatory bowel disease, some autoimmune conditions, immunoglobulin deficiencies, blood malignancies, infections and irritable bowel syndrome. Therefore, the differential diagnosis of ME may be challenging. The diagnosis of ME needs to be driven by predominant symptoms and patient history. However, it is often difficult to achieve an immediate identification of the underlying condition, and a broad variety of diagnostic tests may be required. Ultimately, long-term surveillance is needed for a final diagnosis in many cases, since a hidden or quiescent condition may be disclosed after a period of latency. In any case, strict collaboration between the clinician and the pathologist is pivotal. The treatment of ME should be personalized, depending on the underlying disease. For gluten-related conditions (celiac disease, gluten sensitivity, wheat allergy, dermatitis herpetiformis), a gluten-free diet may be proposed. For other conditions, a targeted etiologic treatment is necessary. In conclusion, ME represents a novel entity that is attracting increasing interest. The growing epidemiologic trend confirms that it will become a common condition in clinical practice.

Helicobacter pylori, liver cirrhosis, and portal hypertension: an updated appraisal

OBJECTIVE

Helicobacter pylori (H. pylori) is the most common cause of gastritis and peptic ulcer. However, H. pylori is even involved in extragastric diseases, and it has been hypothesized that H. pylori could be a risk factor for several hepatic diseases. For instance, a direct involvement of H. pylori in the development of portal hypertension (PH) in cirrhotic patients has been postulated.

METHODS

We performed a literature search in major databases to elucidate the relationship between H. pylori, portal hypertension, and liver cirrhosis.

RESULTS

The effect of H. pylori on PH may be multifactorial. Endothelial dysfunction, alterations in the vasodilating dynamics, and neoangiogenesis are the most appealing theories about this issue, but the proofs come mainly from experimental studies, therefore a solid pathophysiological basis is still to be demonstrated. Congestive gastropathy (CG) and gastric antral vascular ectasia (GAVE) are two common endoscopic entities responsible for acute/chronic upper gastrointestinal bleeding, and a link with H. pylori has been hypothesized: the gastric mucosa, exposed to H. pylori, could develop both inflammatory microcirculatory alterations and thrombi, resembling the histologic pattern of GAVE.

CONCLUSIONS

Despite clues for an association between H. pylori and PH have been shown, these evidences are mostly experimental, therefore, in the absence of a direct proof on human beings, the role of H. pylori in the development of PH is uncertain. However, since this germ may be a cause of peptic ulcer, it should be found and eradicated in cirrhotic patients to reduce the risk of blood loss anemia.

Helicobacter pylori DNA isolation in the stool: an essential pre-requisite for bacterial noninvasive molecular analysis

PURPOSE

Real-time polymerase chain reaction (RT-PCR) is a widely used technique for bacterial and viral infection diagnosis. Herein, we report our preliminary experience in retrieving H. pylori genetic sequences in stools and analyzing genotypic clarithromycin resistance by RT-PCR (noninvasive), with the aim of comparing this procedure with that performed on biopsy samples (invasive).

MATERIALS AND METHODS

After 'in vitro' demonstration of H. pylori DNA detection from pure and stool-mixed bacteria, 52 consecutive patients at the first diagnosis of infection were investigated. DNA was extracted from biopsy tissue and stool samples (THD^® Fecal Test, Italy). RT-PCR was performed to detect 23S rRNA encoding bacterial subunit gene and search A2143G, A2142C, A2142G point mutations for clarithromycin resistance assessment.

RESULTS

RT-PCR showed H. pylori positive DNA in all infected patients with full concordance between tissue and stool detection (100%). We found A2143G mutation in 10 (19.2%), A2142G in 4 (7.7%) and A2142C in 5 (9.6%) patients; there was a full agreement between biopsy and fecal samples. A2143G was found in all the four A2142G positive cases and in three out of the five A2142C positive strains. Overall clarithromycin resistance rate in our series was 23%.

CONCLUSIONS

Despite the need of confirmation on large sample, stool RT-PCR analysis could represent a feasible tool to detect H. pylori DNA sequences and antibiotic resistance point mutations. As compared to tissue molecular analysis, this technique is noninvasive, with potential advantages such as improvement of patient compliance, reduction of diagnostic procedure time/cost and improvement of therapeutic outcome.

Surveillance of Helicobacter pylori Antibiotic Susceptibility in Indonesia: Different Resistance Types among Regions and with Novel Genetic Mutations

Information regarding Helicobacter pylori antibiotic resistance in Indonesia was previously inadequate. We assessed antibiotic susceptibility for H. pylori in Indonesia, and determined the association between virulence genes or genetic mutations and antibiotic resistance. We recruited 849 dyspeptic patients who underwent endoscopy in 11 cities in Indonesia. E-test was used to determine the minimum inhibitory concentration of five antibiotics. PCR-based sequencing assessed mutations in 23S rRNA, rdxA, gyrA, gyrB, and virulence genes. Next generation sequencing was used to obtain full-length sequences of 23S rRNA, infB, and rpl22. We cultured 77 strains and identified 9.1% with clarithromycin resistance. Low prevalence was also found for amoxicillin and tetracycline resistance (5.2% and 2.6%, respectively). In contrast, high resistance rates to metronidazole (46.7%) and levofloxacin (31.2%) were demonstrated. Strains isolated from Sumatera Island had significantly higher metronidazole resistance than those from other locations. Metronidazole resistant strains had highly distributed rdxA amino acid substitutions and the 23S rRNA A2143G mutation was associated with clarithromycin resistance (42.9%). However, one strain with the highest MIC value had a novel mutation in rpl22 without an A2143G mutation. Mutation at Asn-87 and/or Asp-91 of gyrA was associated with levofloxacin-resistance and was related to gyrB mutations. In conclusions, although this is a pilot study for a larger survey, our current data show that Indonesian strains had the high prevalence of metronidazole and levofloxacin resistance with low prevalence of clarithromycin, amoxicillin, and tetracycline resistance. Nevertheless, clarithromycin- or metronidazole-based triple therapy should be administered with caution in some regions of Indonesia.

Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal

Background

The prevalence of Helicobacter pylori antibiotic susceptibility in the Nepalese strains is untracked. We determined the antibiotic susceptibility for H. pylori and analyzed the presence of genetic mutations associated with antibiotic resistance in Nepalese strains.

Results

This study included 146 consecutive patients who underwent gastroduodenal endoscopy in Kathmandu, Nepal. Among 42 isolated H. pylori, there was no resistance to amoxicillin and tetracycline. In contrast, similar with typical South Asian patterns; metronidazole resistance rate in Nepalese strains were extremely high (88.1 %, 37/42). Clarithromycin resistance rate in Nepalese strains were modestly high (21.4 %, 9/42). Most of metronidazole resistant strains had highly distributed rdxA and frxA mutations, but were relative coincidence without a synergistic effect to increase the minimum inhibitory concentration (MIC). Among strains with the high MIC, 63.6 % (7/11) were associated with frameshift mutation at position 18 of frxA with or without rdxA involvement. However, based on next generation sequencing data we found that one strain with the highest MIC value had a novel mutation in the form of amino acid substituted at Ala-212, Gln-382, Ile-485 of dppA and Leu-145, Thr-168, Glu-117, Val-121, Arg-221 in dapF aside from missense mutations in full-length rdxA. Mutations at Asn-87 and/or Asp-91 of the gyrA were predominantly in levofloxacin-resistant strains. The gyrB mutation had steady relationship with the gyrA 87–91 mutations. Although three (44.4 %) and two (22.2 %) of clarithromycin resistant strains had point mutation on A2143G and A2146G, we confirmed the involvement of rpl22 and infB in high MIC strains without an 23SrRNA mutation.

Conclusions

The rates of resistance to clarithromycin, metronidazole and levofloxacin were high in Nepalese strains, indicating that these antibiotics-based triple therapies are not useful as first-line treatment in Nepal. Bismuth or non-bismuth-based quadruple regimens, furazolidone-based triple therapy or rifabutin-based triple therapy may become alternative strategy in Nepal.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0873-6) contains supplementary material, which is available to authorized users.