Pylera for the eradication of Helicobacter pylori infection

Bacterial Membrane Vesicles as a Novel Strategy for Extrusion of Antimicrobial Bismuth Drug in Helicobacter pylori

Bacterial antibiotic resistance is a major threat to human health. A combination of antibiotics with metals is among the proposed alternative treatments. Only one such combination is successfully used in clinics; it associates antibiotics with the metal bismuth to treat infections by Helicobacter pylori. This bacterial pathogen colonizes the human stomach and is associated with gastric cancer, killing 800,000 individuals yearly. The effect of bismuth in H. pylori treatment is not well understood in particular for sublethal doses such as those measured in the plasma of treated patients. We addressed this question and observed that bismuth induces the formation of homogeneously sized membrane vesicles (MVs) with unique protein cargo content enriched in bismuth-binding proteins, as shown by quantitative proteomics. Purified MVs of bismuth-exposed bacteria were strongly enriched in bismuth as measured by inductively coupled plasma optical emission spectrometry (ICP-OES), unlike bacterial cells from which they originate. Thus, our results revealed a novel function of MVs in bismuth detoxification, where secreted MVs act as tool to discard bismuth from the bacteria. Bismuth also induces the formation of intracellular polyphosphate granules that are associated with changes in nucleoid structure. Nucleoid compaction in response to bismuth was established by immunogold electron microscopy and refined by the first chromosome conformation capture (Hi-C) analysis of H. pylori. Our results reveal that even low doses of bismuth induce profound changes in H. pylori physiology and highlight a novel defense mechanism that involves MV-mediated bismuth extrusion from the bacteria and a probable local DNA protective response where polyphosphate granules are associated with nucleoid compaction.

Nickel, an essential virulence determinant of Helicobacter pylori: Transport and trafficking pathways and their targeting by bismuth

Metal acquisition and intracellular trafficking are crucial for all cells and metal ions have been recognized as virulence determinants in bacterial pathogens. Nickel is required for the pathogenicity of H. pylori. This bacterial pathogen colonizes the stomach of about half of the human population worldwide and is associated with gastric cancer that is responsible for 800,000 deaths per year. H. pylori possesses two nickel-enzymes that are essential for in vivo colonization, a [NiFe] hydrogenase and an abundant urease responsible for resistance to gastric acidity. Because of these two enzymes, survival of H. pylori relies on an important supply of nickel, implying tight control strategies to avoid its toxic accumulation or deprivation. H. pylori possesses original mechanisms for nickel uptake, distribution, storage and trafficking that will be discussed in this review. During evolution, acquisition of nickel transporters and specific nickel-binding proteins has been a decisive event to allow Helicobacter species to become able to colonize the stomach. Accordingly, many of the factors involved in these mechanisms are required for mouse colonization by H. pylori. These mechanisms are controlled at different levels including protein interaction networks, transcriptional, post-transcriptional and post-translational regulation. Bismuth is another metal used in combination with antibiotics to efficiently treat H. pylori infections. Although the precise mode of action of bismuth is unknown, many targets have been identified in H. pylori and there is growing evidence that bismuth interferes with the essential nickel pathways. Understanding the metal pathways will help improve treatments against H. pylori and other pathogens.

Medicinal inorganic chemistry: an updated review on the status of metallodrugs and prominent metallodrug candidates

Metallodrugs correspond to a small portion of all available drugs in the market and, yet, some of them are among the most used and important drugs in modern medicine. However, medicinal inorganic chemistry remains an underestimated area within medicinal chemistry and the main reason is the mislead association of metals to toxic agents. Thus, in this review, the potential of medicinal inorganic chemistry in drug designing is highlighted through a description of the current status of metallodrugs and metallodrug candidates in advanced clinical trials. The broad spectrum of application of metal-based drugs in medicine for both therapy and diagnosis is addressed by the extensive list of examples presented herein.

European Registry on Helicobacter pylori management (Hp-EuReg): patterns and trends in first-line empirical eradication prescription and outcomes of 5 years and 21 533 patients

OBJECTIVE

The best approach for Helicobacter pylori management remains unclear. An audit process is essential to ensure clinical practice is aligned with best standards of care.

DESIGN

International multicentre prospective non-interventional registry starting in 2013 aimed to evaluate the decisions and outcomes in H. pylori management by European gastroenterologists. Patients were registered in an e-CRF by AEG-REDCap. Variables included demographics, previous eradication attempts, prescribed treatment, adverse events and outcomes. Data monitoring was performed to ensure data quality. Time-trend and geographical analyses were performed.

RESULTS

30 394 patients from 27 European countries were evaluated and 21 533 (78%) first-line empirical H. pylori treatments were included for analysis. Pretreatment resistance rates were 23% to clarithromycin, 32% to metronidazole and 13% to both. Triple therapy with amoxicillin and clarithromycin was most commonly prescribed (39%), achieving 81.5% modified intention-to-treat eradication rate. Over 90% eradication was obtained only with 10-day bismuth quadruple or 14-day concomitant treatments. Longer treatment duration, higher acid inhibition and compliance were associated with higher eradication rates. Time-trend analysis showed a region-dependent shift in prescriptions including abandoning triple therapies, using higher acid-inhibition and longer treatments, which was associated with an overall effectiveness increase (84%-90%).

CONCLUSION

Management of H. pylori infection by European gastroenterologists is heterogeneous, suboptimal and discrepant with current recommendations. Only quadruple therapies lasting at least 10 days are able to achieve over 90% eradication rates. European recommendations are being slowly and heterogeneously incorporated into routine clinical practice, which was associated with a corresponding increase in effectiveness.

Bismuth quadruple regimen with tetracycline or doxycycline versus three-in-one single capsule as third-line rescue therapy for Helicobacter pylori infection: Spanish data of the European Helicobacter pylori Registry (Hp-EuReg)

BACKGROUND

Different bismuth quadruple therapies containing proton-pump inhibitors, bismuth salts, metronidazole, and a tetracycline have been recommended as third-line Helicobacter pylori eradication treatment after failure with clarithromycin and levofloxacin.

AIM

To evaluate the efficacy and safety of third-line treatments with bismuth, metronidazole, and either tetracycline or doxycycline.

METHODS

Sub-study with Spanish data of the "European Registry on H pylori Management" (Hp-EuReg), international multicenter prospective non-interventional Registry of the routine clinical practice of gastroenterologists. After previous failure with clarithromycin- and levofloxacin-containing therapies, patients receiving a third-line regimen with 10/14-day bismuth salts, metronidazole, and either tetracycline (BQT-Tet) or doxycycline (BQT-Dox), or single capsule (BQT-three-in-one) were included. Data were registered at AEG-REDCap database. Univariate and multivariate analyses were performed.

RESULTS

Four-hundred and fifty-four patients have been treated so far: 85 with BQT-Tet, 94 with BQT-Dox, and 275 with BQT-three-in-one. Average age was 53 years, 68% were women. Overall modified intention-to-treat and per-protocol eradication rates were 81% (BQT-Dox: 65%, BQT-Tet: 76%, BQT-three-in-one: 88%) and 82% (BQT-Dox: 66%, BQT-Tet: 77%, BQT-three-in-one: 88%), respectively. By logistic regression, higher eradication rates were associated with compliance (OR = 2.96; 95% CI = 1.01-8.84) and no prior metronidazole use (OR = 1.96; 95% CI = 1.15-3.33); BQT-three-in-one was superior to BQT-Dox (OR = 4.46; 95% CI = 2.51-8.27), and BQT-Tet was marginally superior to BQT-Dox (OR = 1.67; 95% CI = 0.85-3.29).

CONCLUSION

Third-line H pylori eradication with bismuth quadruple treatment (after failure with clarithromycin and levofloxacin) offers acceptable efficacy and safety. Highest efficacy was found in compliant patients and those taking 10-day BQT-three-in-one or 14-day BQT-Tet. Doxycycline seems to be less effective and therefore should not be recommended.

Bismuth Concentrations in Patients Treated in Real-Life Practice with a Bismuth Subcitrate-Metronidazole-Tetracycline Preparation: The SAPHARY Study

INTRODUCTION

A fixed-dose association of bismuth subcitrate, metronidazole and tetracycline (BMT) (Pylera^®, Allergan, NJ, USA) was made available in France in 2013 for the eradication of Helicobacter pylori. Due to a historical issue of bismuth encephalopathy, the French Health Authorities requested a study of blood and plasma bismuth concentrations with BMT in daily practice.

AIMS

The aim of the study was to measure eventual bismuth accumulation and neurological toxicity in patients prescribed BMT.

METHODS

Patients initiating BMT for H. pylori between March 2014 and December 2015 were included. A blood sample was taken before first BMT intake and 24 h after the last intake, for assay of bismuth. A concentration > 50 μg/L was considered abnormal. Neurological complaints were assessed at inclusion, at the end of the 10-day treatment course, and 28 days later.

RESULTS

202 patients were included, of whom 190 took at least one dose of BMT, and 167 provided both required blood samples. Mean blood bismuth concentrations after the BMT course were 16.9 μg/L (95% confidence interval 15.6-18.3). Concentrations were > 50 μg/L (56.0 μg/L and 50.9 μg/L) in two elderly patients, one of whom presented mild, transient memory impairment during treatment. Non-serious neurological symptoms occurred in 20% of all patients and treatment failure was documented in 5% of patients.

CONCLUSIONS

In this study measuring blood bismuth concentrations in real-life practice, in < 1% of patients the BMT course resulted in blood bismuth concentrations > 50 μg/L. No serious neurological adverse events were observed.

STUDY REGISTRATION

EU-PAS register EUPAS3142 at www.encepp.eu ; ENCePP study seal.

Treatment of Helicobacter pylori infection in atrophic gastritis

Helicobacter pylori (Hp) is a major human pathogen causing chronic, progressive gastric mucosal damage and is linked to gastric atrophy and cancer. Hp-positive individuals constitute the major reservoir for transmission of infection. There is no ideal treatment for Hp. Hp infection is not cured by a single antibiotic, and sometimes, a combined treatment with three or more antibiotics is ineffective. Atrophic gastritis (AG) is a chronic disease whose main features are atrophy and/or intestinal metaplasia of the gastric glands, which arise from long-standing Hp infection. AG is reportedly linked to an increased risk for gastric cancer, particularly when extensive intestinal metaplasia is present. Active or past Hp infection may be detected by conventional methods in about two-thirds of AG patients. By immunoblotting of sera against Hp whole-cell protein lysates, a previous exposure to Hp infection is detected in all AG patients. According to guidelines, AG patients with Hp positivity should receive eradication treatment. The goals of treatment are as follows: (1) Cure of infection, resolution of inflammation and normalization of gastric functions; (2) possible reversal of atrophic and metaplastic changes of the gastric mucosa; and (3) prevention of gastric cancer. An ideal antibiotic regimen for Hp should achieve eradication rates of approximately 90%, and complex multidrug regimens are required to reach this goal. Amongst the factors associated with treatment failure are high bacterial load, high gastric acidity, Hp strain, smoking, low compliance, overweight, and increasing antibiotic resistance. AG, when involving the corporal mucosa, is linked to reduced gastric acid secretion. At a non-acidic intra-gastric pH, the efficacy of the common treatment regimens combining proton pump inhibitors with one or more antibiotics may not be the same as that observed in patients with Hp gastritis in an acid-producing stomach. Although the efficacy of these therapeutic regimens has been thoroughly tested in subjects with Hp infection, there is a paucity of evidence in the subgroup of patients with AG. Bismuth-based therapy may be an attractive treatment in the specific setting of AG, and specific studies on the efficacy of bismuth-based therapies are needed in patients with AG.

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.

Quadruple therapy versus standard triple therapy for eradication of Helicobacter pylori in Kuwait

BACKGROUND AND STUDY AIMS

Chronic infection caused by Helicobacter pylori (H. pylori) is associated with chronic gastritis, peptic ulcer disease, and gastric cancer. Eradication of H. pylori reduces morbidity of chronic gastritis and incidence of gastric cancer in high-risk population. We aimed at testing the efficacy of clarithromycin-based triple therapy and bismuth-based quadruple therapy for eradicating H. pylori in patients with chronic gastritis in Kuwait.

PATIENTS AND METHODS

A total of 218 dyspeptic patients from different countries who were proved to have chronic gastritis by endoscopy and gastric biopsy were enroled. All of them were naïve to H. pylori eradication therapy. They were randomised into two groups: group A, received triple therapy (omeprazole, amoxicillin, and clarithromycin) for 10days; and group B, received quadruple therapy (omeprazole, bismuth subcitrate potassium, tetracycline, and metronidazole) for 10days. All patients were tested for eradication of H. pylori by carbon-13 urea breath test 4weeks after treatment.

RESULTS

Total response rate of eradication therapy in both groups was 77.5% (n=169). However, group B (n=100) had a higher eradication rate (88%) than group A (n=118) (68.6%). H. pylori eradication rate was significantly higher in males (84.2%) than females (70.2%) in both groups (p<0.01). There were no differences in eradication rates with regard to median age or nationality.

CONCLUSION

Bismuth-based quadruple therapy is more effective as a first-line therapy than clarithromycin-based triple therapy for eradicating H. pylori in patients with H. pylori-related chronic gastritis in Kuwait.

Attempts to enhance the eradication rate of Helicobacter pylori infection

Increasing rates of antimicrobial resistance to clarithromycin and metronidazole present challenges in maintaining optimal eradication rates. Knowledge of local antibiotic resistance and consumption pattern is important in selecting a reliable regimen. In addition, adverse effect profiles of therapeutic regimens are important and must be addressed to enhance compliance rates. Various methods of enhancing the eradication rates of Helicobacter pylori (H. pylori) have been investigated, including changing combinations or durations of established drugs, adding adjuvant drugs, or development of new molecules or agents. Bismuth-containing quadruple, sequential, concomitant, and levofloxacin-based triple therapies are replacing the long-standing standard of the triple regimen. Despite the encouraging results of these regimens, individualized approaches like treatment after antibiotics resistance test or CYP2C19 genotyping would be the mainstream of future therapy. Because scientific, economic, and technical problems make these advance therapies unfit for widespread use, future development for H. pylori therapy should be directed to overcome individualized antibiotic resistance. Although various novel regimens and additive agents have indicated favorable outcomes, more studies or validations are needed to become a mainstream H. pylori therapy.

Current options for the treatment of Helicobacter pylori

INTRODUCTION

Treatment of Helicobacter pylori (H. pylori) infection is crucial for prevalent disease's management, including gastritis, peptic ulcer and gastric cancer, whereas novel extradigestive causal associations are increasingly being recognized. Despite long-standing efforts, there is not as yet an optimal empirical therapy to eradicate H. pylori.

AREAS COVERED

In the present article the authors review current options for H. pylori eradication. Advantages and disadvantages of each of the recommended regimens, and the perspectives for their rational use in clinical practice, are critically discussed.

EXPERT OPINION

The continuous rising of antimicrobial resistance has accounted for the declined efficiency of standard triple therapies, yielding < 70% eradication in most countries. Alternative first-line strategies have been proposed and largely validated and are now replacing standard-of-care therapies in areas with a high incidence of clarithromycin-resistance (> 20%). Such treatments include the bismuth-containing quadruple therapy, concomitant, sequential and levofloxacin-based regimens, the later mainly designated, together with rifabutin-based therapies as second-line/rescue options. Clinicians should be aware of the local resistance pattern and maintain first-line eradication to levels > 90% (per-protocol efficacy). This will prevent both exposing the patient to repeated treatments and spreading of secondary antimicrobial resistance. In the future, perspectives of tailored therapy and a prophylactic vaccine will obviate any treatment concern.

The effects of varying acidity on Helicobacter pylori growth and the bactericidal efficacy of ampicillin

BACKGROUND

Penicillins inhibit cell wall synthesis; therefore, Helicobacter pylori must be dividing for this class of antibiotics to be effective in eradication therapy. Identifying growth responses to varying medium pH may allow design of more effective treatment regimens.

AIM

To determine the effects of acidity on bacterial growth and the bactericidal efficacy of ampicillin.

METHODS

H. pylori were incubated in dialysis chambers suspended in 1.5-L of media at various pHs with 5 mM urea, with or without ampicillin, for 4, 8 or 16 h, thus mimicking unbuffered gastric juice. Changes in gene expression, viability and survival were determined.

RESULTS

At pH 3.0, but not at pH 4.5 or 7.4, there was decreased expression of ~400 genes, including many cell envelope biosynthesis, cell division and penicillin-binding protein genes. Ampicillin was bactericidal at pH 4.5 and 7.4, but not at pH 3.0.

CONCLUSIONS

Ampicillin is bactericidal at pH 4.5 and 7.4, but not at pH 3.0, due to decreased expression of cell envelope and division genes with loss of cell division at pH 3.0. Therefore, at pH 3.0, the likely pH at the gastric surface, the bacteria are nondividing and persist with ampicillin treatment. A more effective inhibitor of acid secretion that maintains gastric pH near neutrality for 24 h/day should enhance the efficacy of amoxicillin, improving triple therapy and likely even allowing dual amoxicillin-based therapy for H. pylori eradication.

Helicobacter pylori Eradication Therapies in the Era of Increasing Antibiotic Resistance: A Paradigm Shift to Improved Efficacy

With the rising prevalence of antimicrobial resistance, the eradication rates of Helicobacter pylori (H. pylori) with standard treatments are decreasing to unacceptable levels (i.e., ≤80%) in most countries. After these disappointing results, several authorities have proposed that infection with H. pylori should be approached and treated as any other bacterial infectious disease. This implicates that clinicians should prescribe empirical treatments yielding a per protocol eradication of at least 90%. In recent years several treatments producing ≥90% cure rates have been proposed including sequential therapy, concomitant quadruple therapy, hybrid (dual-concomitant) therapy, and bismuth-containing quadruple therapy. These treatments are likely to represent the recommended first-line treatments in the near future. In the present paper, we are considering a series of critical issues regarding currently available means and approaches for the management of H. pylori infection. Clinical needs and realistic endpoints are taken into account. Furthermore, emerging strategies for the eradication of H. pylori and the existing evidence of their clinical validation and widespread applicability are discussed.

Helicobacter pylori Eradication Therapies in the Era of Increasing Antibiotic Resistance: A Paradigm Shift to Improved Efficacy

With the rising prevalence of antimicrobial resistance, the eradication rates of Helicobacter pylori (H. pylori) with standard treatments are decreasing to unacceptable levels (i.e., ≤80%) in most countries. After these disappointing results, several authorities have proposed that infection with H. pylori should be approached and treated as any other bacterial infectious disease. This implicates that clinicians should prescribe empirical treatments yielding a per protocol eradication of at least 90%. In recent years several treatments producing ≥90% cure rates have been proposed including sequential therapy, concomitant quadruple therapy, hybrid (dual-concomitant) therapy, and bismuth-containing quadruple therapy. These treatments are likely to represent the recommended first-line treatments in the near future. In the present paper, we are considering a series of critical issues regarding currently available means and approaches for the management of H. pylori infection. Clinical needs and realistic endpoints are taken into account. Furthermore, emerging strategies for the eradication of H. pylori and the existing evidence of their clinical validation and widespread applicability are discussed.