Simplified 10-day bismuth triple therapy for cure of Helicobacter pylori infection: experience from clinical practice in a population with a high frequency of metronidazole resistance

The effect of antibiotic resistance on Helicobacter pylori eradication efficacy: A systematic review and meta-analysis

BACKGROUND

The occurrence of antibiotic-resistant strains has been rapidly increasing due to the wide use of antibiotics. To evaluate the current effects of antibiotic resistance on Helicobacter pylori eradication efficacy, we conducted this systematic review and meta-analysis.

METHODS

Literature searches were conducted in the following databases: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Statistical analysis was performed using STATA version 12.0 (StataCorp LP, College Station, TX, USA).

RESULTS

A total of 120 studies, including 28 707 patients, were assessed. Only first-line therapy was considered. The pooled RR of eradication rate in patients with Helicobacter pylori strains sensitive versus resistant to clarithromycin was 0.682 (95% CI: 0.636-0.731). The pooled RR of eradication rate in patients with Helicobacter pylori strains sensitive versus resistant to metronidazole was 0.843 (95% CI: 0.810-0.877). The pooled RR of eradication rate in patients with Helicobacter pylori strains sensitive versus resistant to levofloxacin was 0.794 (95% CI: 0.669-0.941). The pooled RR of eradication rate in patients with Helicobacter pylori strains sensitive versus resistant to dual clarithromycin and metronidazole was 0.674 (95% CI: 0.590-0.770).

CONCLUSION

Antibiotic resistance causes a decrease in the eradication rate of H pylori today. Quadruple concomitant therapy may overcome the declining H pylori eradication rate caused by metronidazole-only resistance.

Laboratory handling of Helicobacter pylori critically influences the results of in-vitro metronidazole resistance determination

In-vitro metronidazole resistance rates of Helicobacter pylori determined by Etest are high, and the predictive value of metronidazole resistance is low. It was hypothesised that altered laboratory methods could reduce the overestimation of resistance and improve the predictive value of the Etest. Pre-treatment isolates (n = 150) of H. pylori from 150 patients were investigated by Etest with incubation for 72 h. Treatment with metronidazole, tetracycline and bismuth for 10 days failed to eradicate H. pylori in 23 patients. After isolate storage for 3 years, resistance determination results by agar dilution and Etest, with incubation for 72 and 31 h, were compared. The rate of metronidazole resistance was reduced significantly during storage, and instability of resistance was associated significantly with treatment outcome. Isolates that retained in-vitro resistance had significantly (p 0.008) higher treatment failure rates (n = 13; 42%) than isolates that lost resistance (n = 3; 9%). The reproducibility achieved by dual testing with agar dilution and Etest was 41% and 70% for +/- 1 and +/- 2 log2 dilutions, respectively, after incubation for 72 h, and 85% and 92%, respectively, after incubation for 31 h. Thus, the predictive value was improved from 25% to 50% by the altered laboratory conditions (p 0.04). MIC values of 2-8 mg/L signified an intermediate risk of treatment failure.

Effect of different doses of furazolidone with amoxicillin and omeprazole on eradication of Helicobacter pylori

BACKGROUND

Resistance to metronidazole is one of the most common reasons for Helicobacter pylori treatment failure with classic triple therapy. In contrast, the clarithromycin-based regimen is not cost-effective for developing countries. Furazolidone is a very good substitute for metronidazole and clarithromycin, but its many side-effects limit widespread use. The aim of the present study was to assess the efficacy of two different doses of furazolidone in combination with amoxycillin and omeprazole.

METHODS

A total of 123 patients with duodenal ulcer were randomized and received the following medications for two weeks. Group A: furazolidone 2 x 200 mg + amoxycillin 2 x 1 g + omeprazole 2 x 20 mg/day. Group B: furazolidone 2 x 50 mg + amoxycillin 2 x 1 g + omeprazole 2 x 20 mg/day. Control endoscopy was performed after 6 weeks and two biopsy specimens from the antrum and two from the corpus were taken for a urease test and histology. Eradication was concluded if all tests were negative for H. pylori.

RESULTS

In total, 110 patients completed the study. Four patients in group A did not tolerate the regimen on day 8 of therapy and were excluded from the study. Serious complications such as fever, and fatigue and dizziness, which occurred in the beginning of the second week of treatment (days 8-10), were more common in group A than in group B (19%, 15.9% and 14.3%, respectively, in group A vs 0% in group B). The eradication rate by per protocol analysis was significantly higher in group A than in group B (88.9%vs 67.9%, respectively, P = 0.008). However, this difference was low and not statistically significant by intention-to-treat analysis (76.2% in group A and 62.3% in group B, P = 0.09).

CONCLUSION

The regimen with a non-reduced dose of furazolidone in combination with amoxycillin and omeprazole was effective when the patients tolerated the drugs and completed the study.

[Evolution of the sensitivity of 235 strains of Helicobacter pylori from 1995 to 1998 and impact of antibiotic treatment]

BACKGROUND

The aim of this study was to investigate the sensitivity of Helicobacter pylori to the antibiotics used in its eradication over a period of four years and to determine the influence of previous treatment on sensitivity.

MATERIAL AND METHODS

During the period from 1995 to 1998 we determined the sensitivity of 235 consecutive Helicobacter pylori isolates to amoxicillin, metronidazole, clarythromycin and tetracycline by means of E-test methodology. The MIC values found were related with the prior use of eradicating treatment.

RESULTS

The percentage of resistant strains were as follows: 23.5% to metronidazole, 12.9% to clarythromycin and 0.7% to tetracycline; none of the strains was resistant to amoxicillin. There were no significant changes in percentage of resistance to the drugs studied over the 4-year period. Resistance to metronidazole and clarythromycin was significantly higher (p 5 0.03 and p < 0.001 respectively) in strains isolated from patients who had received previous treatment.

CONCLUSIONS

Monitorization of H. pylori sensitivity to the drugs used in its eradication is particularly important in patients who have undergone prior treatment.

Retreatment of Helicobacter pylori infection after initial treatment failure

OBJECTIVES

Helicobacter pylori treatment regimens fail to cure the infection in at least 10-20% of patients undergoing initial treatment. Retreatment strategies for patients who have failed initial treatment for H. pylori infection remain poorly described.

METHODS

The literature describing the frequency of H. pylori treatment failure and factors leading to failure is reviewed. The role of antibiotic resistance is discussed and clinical studies assessing success rates according to antibiotic resistance are described. Clinical trials evaluating the treatment success rates for a second episode of treatment are discussed.

RESULTS

The literature describing retreatment of failed H. pylori infection remains limited. The existing data support the use of bismuth-based quadruple therapy or ranitidine bismuth citrate (RBC)-based triple therapy as the preferred agents after initial treatment failure.

CONCLUSION

Further studies are needed to better define the optimal second treatment regimen after failed H. pylori treatment.

A randomized controlled comparison of three quadruple therapy regimens in a population with low Helicobacter pylori eradication rates

BACKGROUND AND AIM

We sought to compare the efficacy and tolerability of an omeprazole/clarithromycin/bismuth/tetracycline-based quadruple therapy to that of a ranitidine/metronidazole/bismuth/tetracycline-based quadruple therapy of 2 or 3 weeks duration in a population with a high prevalence of metronidazole-resistant Helicobacter pylori and low triple therapy eradication rates.

METHODS

Two hundred and twenty-one patients who presented endoscopically proven duodenal ulcers and a positive rapid urease test were randomized to receive either: (i) omeprazole 20 mg b.i.d., clarithromycin 250 mg b.i.d., bismuth subcitrate 240 mg b.i.d. and tetracycline 500 mg b.i.d (OCBT) for 2 weeks; (ii) ranitidine 300 mg b.i.d., metronidazole 500 mg b.i.d, bismuth subcitrate 240 mg b.i.d. and tetracycline 500 mg b.i.d. (RMBT2) for 2 weeks; or (iii) ranitidine 300 mg b.i.d., metronidazole 500 mg b.i.d, bismuth subcitrate 240 mg b.i.d. and tetracycline 500 mg b.i.d. (RMBT3) for 3 weeks. Patients were interviewed 2 weeks after the completion of therapy to review compliance and side-effects. Eradication of H. pylori was assessed 8 weeks after the completion of therapy with the use of a 14C-urea breath test.

RESULTS

The per-protocol eradication rate was significantly higher with OCBT (88%) than RMBT2 (73%) or RMBT3 (71%) (P<0.05). The intent-to-treat eradication rate was numerically higher with OCBT (80%) than RMBT2 (68%) or RMBT3 (68%), although this difference did not reach statistical significance (P=0.09). Per-protocol or intent-to-treat eradication rates were similar with RMBT2 and RMBT3. There were significantly greater side-effects with the RMBT2 regimen.

CONCLUSIONS

The omeprazole/clarithromycin/bismuth/tetracycline-based quadruple therapy provides higher H. pylori eradication rates than the ranitidine/metronidazole/bismuth/tetracycline-based quadruple therapy when administered per protocol. The prolongation of the latter regimen from 2 to 3 weeks did not increase eradication rates.

Helicobacter pylori infection--current treatment practice

Helicobacter pylori infection, which is present in 30 - 60% of the population in developed countries and in more than 60% in developing countries, is established to be a major cause of gastritis, peptic ulcer disease and gastric cancer. Eradication therapy has been incorporated into clinical practice over the past 15 years. Treatment regimens include a 2 week bismuth-based triple therapy (a bismuth compound plus metronidazole, tetracycline or amoxycillin), a 1 week proton-pump inhibitor (PPI)-based triple therapy and a 1 week ranitidine bismuth citrate (RBC)-based triple therapy (a PPI or RBC plus any two of the three antibiotics, metronidazole, amoxycillin and clarithromycin). These regimens achieve eradication rates of >> 80%. H. pylori resistance to metronidazole and clarithromycin decreases the clinical efficacy of most regimens, despite the high eradication rates for resistant strains achieved by the RBC-triple therapy in some recent trials. The dose of antibiotics (especially clarithromycin) and the duration of treatment may also influence the eradication rate. Doctors' beliefs impact on clinical practice and, thus, influence the clinical application of eradication therapy. Whereas peptic ulcer disease and primary gastric low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma) have become established as definite indications for eradication therapy, there remain controversies surrounding non-ulcer dyspepsia, gastro-oesophageal reflux disease, atrophic gastritis, intestinal metaplasia, use of non-steroidal anti-inflammatory drugs (NSAIDs) and H. pylori-related extradigestive diseases.

Solubility, absorption, and anti-Helicobacter pylori activity of bismuth subnitrate and colloidal bismuth subcitrate: In vitro data Do not predict In vivo efficacy

OBJECTIVES

The aim of this study was to compare the dissolution, bioavailability, and anti-Helicobacter pylori activity of bismuth subnitrate and colloidal bismuth subcitrate. This could, first, provide insights into the mechanism of action of bismuth and, second, help to develop optimal therapeutic strategies.

METHODS

Solubility and aquated size of bismuth species were determined in human gastric juice, while absorption into blood and urinary excretion of bismuth was determined in volunteers. Activity against H. pylori was determined in vitro in the presence and absence of antibiotics, while H. pylori eradication was compared in vivo.

RESULTS

Bismuth from colloidal bismuth subcitrate was at least 10% soluble and ultrafilterable and was absorbed in volunteers (>0.5%), whereas that from bismuth subnitrate was insoluble and not absorbed (<0.01%). Colloidal bismuth subcitrate was active against H. pylori (mean inhibitory concentration, </=12.5 microg/ml), while bismuth subnitrate was inactive (>400 microg/ml); neither was synergistic with antibiotics. With in vivo triple therapy, bismuth subnitrate was as effective as colloidal bismuth subcitrate in eradicating H. pylori (74% and 70% eradicated, respectively).

CONCLUSIONS

Colloidal bismuth subcitrate, unlike bismuth subnitrate, is partially soluble, absorbed in humans, and directly toxic to H. pylori in vitro. Surprisingly, however, these preparations had similar efficacy in vivo against H. pylori within triple therapy, suggesting that bismuth compounds may also exhibit indirect antimicrobial effects. We propose that this is an effect on the gastric mucus layer. Nonabsorbable bismuth compounds should be preferentially considered in bismuth-based therapies against H. pylori, as they would minimize toxicity while maintaining efficacy.

Cure of Helicobacter pylori infection after failed primary treatment: one-center results from 120 patients

BACKGROUND

Treatment with a proton pump inhibitor (PPI) and antimicrobials cures Helicobacter pylori infection in about 90% of patients. This is a retrospective overview of our studies aiming to cure the infection in all compliant patients with failed initial therapy.

METHODS

We retreated 120 (19% of 644) H. pylori-infected patients whose initial therapy had failed. The retreatments included (i) triple therapy (TT): colloidal bismuth subcitrate, metronidazole, amoxicillin (or tetracycline); (ii) quadruple therapy (QT): TT and a PPI; or (iii) high doses of both a PPI and clarithromycin combined with a further 1-3 individually selected antimicrobials. The eradication results were determined after 6-12 months.

RESULTS

The 1st retreatment was successful in 70 of 120 patients. The 2nd retreatment cured 25 of the remaining 42 patients, the 3rd 13 of 17, and the 4th the last 4 patients. The cumulative eradication rate (ITT) was 93% (95% CI: 88.9%-97.9%; 8 patients withdrew after a failed 1st retreatment) and the rate was 100% in the remaining 112 patients who accepted several retreatments. The 1st retreatment with TT cured 23% (95% CI: 12%-34%) of 57 patients and QT 85% (95% CI: 74%-96%) of 41 patients who had initially undergone a failed metronidazole-based treatment. All retreatments were well tolerated.

CONCLUSIONS

In this study, high doses of a PPI and clarithromycin combined with 1-3 antimicrobials according to susceptibility data proved to be the best drug combination in the cure of H. pylori infection after failed primary treatment. Giving imidazole- and bismuth-based QT (without clarithromycin) as the first-line treatment of H. pylori infection ensures that the number of failures remains low.

Double-blind comparison of absorbable colloidal bismuth subcitrate and nonabsorbable bismuth subnitrate in the eradication of Helicobacter pylori and the relief of nonulcer dyspepsia

BACKGROUND

Bismuth is widely used for the eradication of H. pylori, especially in developing countries, although there are concerns over its neurotoxicity. Whether bismuth has to be absorbed in humans to act against H. pylori is not known. In this study, we compared "absorbable" (colloidal bismuth subcitrate) and "nonabsorbable" (bismuth subnitrate) bismuth as part of triple therapy in the eradication of H. pylori.

MATERIALS AND METHODS

A double-blind, randomized, placebo-controlled trial was carried out with 120 H. pylori-positive patients with nonulcer dyspepsia. Group CBS + Ab (n = 35) received colloidal bismuth subcitrate (one tablet qds), amoxicillin (500 mg qds), and metronidazole (400 mg tds). Group BSN + Ab (n = 35) received bismuth subnitrate (two tablets tds) and the same antibiotics. Group Ab (n = 35) received placebo bismuth (two tablets tds) and the antibiotics. Group BSN (n = 15) received bismuth subnitrate (two tablets tds) and placebo antibiotics. Bismuth was taken for 4 weeks and the antibiotics for the first 2 weeks. H. pylori eradication, side effects, compliance, pre- and post-treatment symptom scores, and bismuth absorption were assessed.

RESULTS

H. pylori eradication was 69%, 83%, 31%, and 0% in CBS + Ab, BSN + Ab, Ab, and BSN, respectively. Side effects, compliance, and symptom relief were similar in all groups, but blood bismuth levels were significantly greater in CBS + Ab than the other three groups.

CONCLUSION

The efficacy of bismuth-based therapies as part of triple therapy in the eradication of H. pylori is unrelated to absorption. Hence, the use of effective but poorly absorbed bismuth preparations should be encouraged for bismuth-based eradication therapies.

[Cost-effectiveness analysis of 2 strategies of Helicobacter pylori eradication: results of a prospective and randomized study in primary care]

BACKGROUND

To analyze cost-effectiveness of two different strategies to treat H. pylori infection in peptic ulcer in the primary care setting.

PATIENTS AND METHODS

Consecutive patients with endoscopic diagnosis of peptic ulcer were randomized to one of two strategies: a) treatment during 7 days with omeprazole, tetracycline, metronidazole and bismuth subcitrate ("quadruple" therapy) and if failure second-line treatment with omeprazole, amoxycillin and clarithromycin during 7 days (OCA7), and b) initial treatment with OCA7 and if failure treatment with "quadruple therapy". End point was eradication 8 weeks after last treatment dose. Direct and indirect costs were estimated (euros, 1997) and a cost-effectiveness analysis using a decision-tree model was undertaken after real clinical data. 95% confidence intervals are given.

RESULTS

After screening 255 patients, 97 were finally included. 48 patients were given strategy a and 49 strategy b. Eradication was obtained (intention-to-treat) in 72.9% (CI 95%: 58.2-84.7) in group a versus 91.8% (CI 95%: 80.4-97.7) (p < 0.05) in group b. Mean cost per case treated was lower in group a (237 versus 268 euros) but cost per case eradicated was lower in group b (320 versus 296 euros). The cost was primarily determined by efficacy.

CONCLUSIONS

Treatment with OCA7 followed by rescue with "quadruple" therapy if failure is more efficient in our area that the inverse strategy. Efficiency is mostly determined by efficacy.

Helicobacter pylori eradication in clinical practice: retreatment rates and costs of competing regimens

OBJECTIVE

To measure outcomes for eradication regimens for Helicobacter pylori infection in routine clinical practice.

DESIGN

Retrospective analysis of an integrated medical and pharmacy claims database identified patients treated from June 1, 1995 through May 31, 1996, and followed the patients' claims until December 31, 1996.

SETTING

The database represented multiple health plans throughout the US.

PATIENTS

Patients were > or = 16 years old, continuously enrolled from April 1, 1995, to December 31, 1996, and met clinical (diagnostic or procedural) criteria.

INTERVENTION

Patient cohorts were treated with bismuth-based triple (n = 98), proton-pump inhibitor (PPI)-based triple (n = 180), or PPI-based dual (n = 337) regimens.

OUTCOME MEASURES

Retreatment; monthly postregimen medical expense, controlling for preregimen expense; and drug cost per successfully treated patient. Cox regression (retreatment analysis) and ANCOVA (postregimen expense analysis) adjusted for age, gender, diagnostic/procedural criteria met by patient, and specialty physician use.

RESULTS

Retreatment rates were higher (p < 0.05) for PPI-based dual than bismuth-based or PPI-based triple-therapy cohorts. Retreatment rates for bismuth- and PPI-based triple-therapy cohorts were not significantly different. Total and follow-up (excluding the first 2 wk of treatment) expenses were higher for retreated than nonretreated patients (p < 0.01). Total expenses were higher for the PPI-dual cohort (p < 0.05) than for triple cohorts. Drug costs per successfully treated patient were $30 for bismuth-based, $172 for PPI-based triple, and $208 for PPI-based dual-therapy regimens.

CONCLUSIONS

PPI-based dual-therapy regimens are not cost-effective in H. pylori treatment. Further study should compare more costly (PPI-based) versus less costly (bismuth-based) triple-therapy regimens.

Metronidazole and clarithromycin resistance amongst Helicobacter pylori isolates from a large metropolitan hospital in the United States

BACKGROUND

Metronidazole and clarithromycin-based therapies are among the most efficacious treatment regimens for H. pylori infection. Resistance to metronidazole or clarithromycin is associated with impaired therapy with these agents. We conducted a retrospective review of susceptibility data to determine the frequency of primary metronidazole and clarithromycin resistance among H. pylori isolates from a single metropolitan hospital in the United States. The database comprised 933 patients who presented at the Digestive Diseases Clinic at the Veterans Affairs Medical Center in Houston between September 1988 and January 1997 with complaints of dyspepsia, abdominal pain and peptic ulcer disease. One hundred and seventy-nine of these patients had both pharmaceutical records available for evaluation and culture and antimicrobial susceptibility data for analysis. The MICs were determined by both E-test and broth microdilution tests. The frequency of primary metronidazole resistance was 37.4% (67/179). The level of primary clarithromycin resistance was 6.1%. Dual metronidazole and clarithromycin resistance was present in approx. 3%. The high level of primary metronidazole and clarithromycin resistance in H. pylori isolates from this metropolitan hospital is such that antimicrobial susceptibility data should be available so that informed choice can be made for specific eradication therapies, especially in patients who fail treatment.

Treatment of Helicobacter pylori

Overwhelming evidence implicates Helicobacter pylori as a significant causative factor in many gastroduodenal diseases. Effective multidrug antimicrobial regimens are available for cure of the infection, so investigative efforts are focusing on cost-effectiveness and treatment outcome in various populations. Potential associations between H. pylori and nongastric disorders are being examined. Recognition that infection is largely acquired during childhood has emphasized the need to study pediatric issues. Posttreatment studies confirm the importance of the bacterium in pathogenesis and relapse of peptic ulcer disease. Antimicrobial resistance has a negative impact on cure of the infection and healing of gastroduodenal lesions. Methodology to evaluate H. pylori antimicrobial susceptibility has been standardized by the National Committee for Clinical Laboratory Standards, and minimum inhibitory concentration breakpoints to standardize resistance assays are being established. Surveillance of H. pylori antimicrobial resistance is underway in a Centers for Disease Control and Prevention multisite project in the United States.