The influence of in vitro nitroimidazole resistance on the efficacy of nitroimidazole-containing anti-Helicobacter pylori regimens: a meta-analysis

Helicobacter pylori diagnosis and therapy in the era of antimicrobial stewardship

The diagnosis and therapy of Helicobacter pylori infection have undergone major changes based on the use the principles of antimicrobial stewardship and increased availability of susceptibility profiling. H. pylori gastritis now recognized as an infectious disease, as such there is no placebo response allowing outcome to be assessed in relation to the theoretically obtainable cure rate of 100%. The recent recognition of H. pylori as an infectious disease has changed the focus to therapies optimized to reliably achieve high cure rates. Increasing antimicrobial resistance has also led to restriction of clarithromycin, levofloxacin, or metronidazole to susceptibility-based therapies. Covid-19 resulted in the almost universal availability of polymerase chain reaction testing in hospitals which can be repurposed to utilize readily available kits to provide rapid and inexpensive detection of clarithromycin resistance. In the United States, major diagnostic laboratories now offer H. pylori culture and susceptibility testing and American Molecular Laboratories offers next-generation sequencing susceptibility profiling of gastric biopsies or stools for the six commonly used antibiotics without need for endoscopy. Current treatment recommendations include (a) only use therapies that are reliably highly effective locally, (b) always perform a test-of-cure, and (c) use that data to confirm local effectiveness and share the results to inform the community regarding which therapies are effective and which are not. Empiric therapy should be restricted to those proven highly effective locally. The most common choices are 14-day bismuth quadruple therapy and rifabutin triple therapy. Prior guidelines and treatment recommendations should only be used if proven locally highly effective.

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.

The Effect of Helicobacter pylori Eradication on Gastric Wall Thickness in Patients Undergoing Laparoscopic Sleeve Gastrectomy

PURPOSE

The most important cause affecting the thickness of the gastric wall other than the tumor is chronic gastritis caused by Helicobacter pylori (Hp), which is most frequently detected in the antrum. This study aims to investigate the effect of bismuth-based treatment (BBT) combined with proton pump inhibitor (PPI) on wall thicknesses measured in the postoperative gastric specimen and early postoperative complications in patients with Hp-positive pre-LSG endoscopic gastric biopsies.

MATERIALS AND METHODS

The patients who underwent LSG procedure for morbid obesity were divided into three groups as follows: Hp-negative, Hp-positive without eradication treatment, and Hp-positive, and LSG was performed after eradication treatment. Macroscopic and microscopic gastric wall thickness measurements were made at a distance of 1 cm from the proximal surgical margin, from the middle part of the specimen, and 1 cm from the distal surgical margin in the gastric specimen and the results were compared.

RESULTS

A total of 132 patients were included in the study, 44 patients in each group. Microscopically measured antrum mucosal thickness was found to be statistically significantly higher in group 2 compared to other groups (groups 1.15, 1.35, 1.16 mm, respectively, p = 0.000). There was no difference between the groups in terms of early complications such as bleeding, wound site infection, or leakage from the staple line within the first 28 days after surgery.

CONCLUSION

This study found that LSG had no effect on early complications due to Hp positivity or eradication of Hp.

KEY POINTS

• The presence of HP increases the wall thickness of the gastric antrum mucosa. • After HP eradication, stomach antrum wall thickness returns to normal. • HP eradication before LSG reduces the wall thickness of the gastric antrum mucosa. • It was determined that HP scanning and eradication before LSG had no effect on postoperative complications.

Annual eradication rate of bismuth-containing quadruple therapy as second-line treatment for Helicobacter pylori infection: A 15-year prospective study at a tertiary hospital in Korea

BACKGROUND

Bismuth-containing quadruple therapy is widely used as second-line treatment for Helicobacter pylori infection. This prospective study investigated the changes in the annual H. pylori eradication rates of quadruple therapy.

METHODS

This study included an intention-to-treat (ITT) population of 452 subjects who failed first-line eradication therapy for H. pylori between 2003 and 2018. All subjects received a 14-day course of bismuth-containing quadruple therapy consisting of esomeprazole (40 mg twice daily), metronidazole (500 mg thrice daily), bismuth subcitrate (120 mg four times daily), and tetracycline (500 mg four times daily). Per-protocol (PP) analysis of data was performed in subjects who followed up with strict treatment adherence. Eradication was confirmed based on the results of the ¹³ C-urea breath test, rapid urease test (CLOtest^® ), and histopathologic evaluation. Compliance and adverse effects were also investigated. A minimal inhibitory concentration test was performed on tissue samples obtained from 103 subjects.

RESULTS

The overall eradication rates following ITT and PP analyses were 78.8% (356/452) and 89.5% (314/351), respectively. The annual eradication success rate did not show significant changes (P = .062 [ITT], P = .857 [PP]) over the 15-year study period. Adverse events were reported in 57.3% of the ITT population. The rates of resistance to metronidazole and tetracycline were 44.7% and 18.4%, respectively.

CONCLUSIONS

Despite high antibiotic resistance rates, no significant reduction in annual eradication rates was observed during the study period.

Appropriateness of Repeating Helicobacter pylori Culture and Susceptibility Testing Following Failure of Individualized Antibiotic Therapy

BACKGROUND

Current guidelines recommend direct Helicobacter pylori culture and antibiotic susceptibility testing following 2 failed eradication attempts. If this process is followed and yet subsequent treatment is unsuccessful, it is unclear whether susceptibility testing should be repeated. This is the first study to examine the appropriateness of repeated H. pylori culture and susceptibility testing following failure of individualized treatment.

METHODS

Between 2007 and 2014, consecutive patients who underwent at least 2 upper gastrointestinal endoscopies with H. pylori culture and susceptibility testing at our institution following several treatment failures were retrospectively identified. Antibiotic susceptibility was recorded and linked to demographic data.

RESULTS

A total of 68 cultures from 34 patients were included (12 (35.3%) men, 41.4 ± 16.6 years), and 20 (58.8%) cultures had a different antibiotic susceptibility profile on repeat testing (8 (23.5%) with new susceptibility and 13 (38.2%) with new resistance). Acquired resistance to clarithromycin, levofloxacin and metronidazole was observed in 9 (26.5%), 2 (5.9%) and 10 (29.4%) cultures, respectively. Subjects with resistance to ≤1 antibiotic at baseline were more likely to develop resistance to at least 1 antibiotic on subsequent culture, compared to subjects with resistance to ≥2 antibiotics at baseline (13 (100%) vs. 5 (23.8%), p < 0.01).

CONCLUSION

Repeating H. pylori culture and susceptibility testing usually yields new antimicrobial susceptibility data. However, the clinical usefulness of this approach remains unclear.

Adhesion and Invasion of Gastric Mucosa Epithelial Cells by Helicobacter pylori

Helicobacter pylori is the main pathogenic bacterium involved in chronic gastritis and peptic ulcer and a class 1 carcinogen in gastric cancer. Current research focuses on the pathogenicity of H. pylori and the mechanism by which it colonizes the gastric mucosa. An increasing number of in vivo and in vitro studies demonstrate that H. pylori can invade and proliferate in epithelial cells, suggesting that this process might play an important role in disease induction, immune escape and chronic infection. Therefore, to explore the process and mechanism of adhesion and invasion of gastric mucosa epithelial cells by H. pylori is particularly important. This review examines the relevant studies and describes evidence regarding the adhesion to and invasion of gastric mucosa epithelial cells by H. pylori.

Eradication Rates of Helicobacter pylori in Korea Over the Past 10 years and Correlation of the Amount of Antibiotics Use: Nationwide Survey

BACKGROUND

The efficacy of proton-pump inhibitor-amoxicillin-clarithromycin therapy for H. pylori eradication has decreased over time.

OBJECTIVE

We assessed the trend of H. pylori eradication rates over the last 10 years and the relationship between the eradication rates and the amount of macrolide antibiotic use in a country with a high prevalence of H. pylori infection.

METHODS

This vast nationwide multicenter study was conducted with 34,139 adults treated for H. pylori infection from January 2001 to December 2010. The defined daily dose per km(2) (DSD) of macrolide antibiotics was calculated (n = 141,019) using the Health Insurance Review & Assessment data base from 2008 to 2010 in the two cities which had the lowest (Jeju city) or highest (Chuncheon city) eradication rate.

RESULTS

The eradication rates of proton-pump inhibitor-amoxicillin-clarithromycin therapy ranged 84.9-87.5% from 2001 to 2007, and those of 2008 to 2010 ranged 80.0-81.4% with a decreasing trend (p < 0.0001). The decreasing trend of eradication rates for the overall first-line therapy was observed only in three of the seven geographic areas in Korea (p < 0.0001). The DSD of macrolide antibiotics was significantly higher in Jeju than Cheunchon city (0.85 vs 0.52, p < 0.0001).

CONCLUSIONS

H. pylori eradication rates with clarithromycin-containing triple therapy in Korea showed a decreasing trend over the past 10 years, although the trend varied among geographic areas. This difference may be associated with the amount of macrolide antibiotic use.

Trends in secondary antibiotic resistance of Helicobacter pylori from 2007 to 2014: has the tide turned?

The current guidelines recommend culture and antibiotic susceptibility testing of Helicobacter pylori following two failed eradication attempts. Where testing is unavailable, epidemiological data for secondary H. pylori resistance are essential to allow for the rational use of antibiotics. The aim of this study was to describe the temporal changes in antibiotic resistance among adults previously treated for H. pylori infections and to identify predictors of resistance. Between 2007 and 2014, consecutive patients undergoing gastroscopy with H. pylori culture and susceptibility testing at our institution following at least two treatment failures were retrospectively identified. Antibiotic susceptibilities were recorded and linked to the demographic data. A total of 1,042 patients were identified, including 739 (70.9%) males, aged 39.3 ± 18.9 years. Resistance to clarithromycin, metronidazole, and levofloxacin was found in 57.2%, 64.4%, and 5.1% of isolates, respectively. Dual resistance to clarithromycin and metronidazole was seen in 39.9%. Over the study period, clarithromycin resistance increased annually in a linear manner (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.03 to 1.14; P < 0.01), levofloxacin resistance decreased annually (OR, 0.78; 95% CI, 0.61 to 0.92; P < 0.01), and metronidazole resistance was nonlinear. Age was an independent predictor of resistance to all antibiotics. Time elapsed predicted resistance for clarithromycin and levofloxacin and dual resistance for clarithromycin-metronidazole. Secondary resistance of H. pylori to clarithromycin and metronidazole remains high. The low secondary resistance to levofloxacin makes it an attractive treatment option in our region for patients following two failed eradication attempts.

Helicobacter pylori eradication in West Asia: A review

The efficacy of first- and second-line Helicobacter pylori (H. pylori) eradication regimens varies considerably in West Asian countries, mainly due to the variable prevalence of resistant organisms. However, no review article has yet evaluated and compared the efficacy of different regimens among different countries of this region. Therefore, we conducted a review to select the best options and provide recommendations for H. pylori treatment in this geographic region. A search through PubMed was carried out to obtain relevant randomized clinical trials published in English language up to June 2013. According to the results, among different therapeutic regimens used as the first-line protocols, 10-d Bismuth-Furazolidone/Metronidazole quadruple therapy, 14-d Clarithromycin-containing hybrid therapy and 14-d quadruple therapy including a proton pump inhibitor + Bismuth + Tetracycline (500 mg QID) + Metronidazole (500 mg TDS) seemed to be appropriate options. Among second-line therapeutic regimens, Bismuth-based quadruple therapies containing Tetracycline and Furazolidone/Metronidazole, triple therapy containing Amoxicillin and Gatifloxacin and Quadruple therapy including Bismuth + Azithromycin and Ofloxacin seemed to be effective options. Third-line therapies were not evaluated in West Asia; most guidelines, however, recommend choosing optimal eradication regimen according to the pattern of antibiotic susceptibility of H. pylori. Although we limited our investigation to H. pylori eradication regimens in West Asia, the clinical significance of the results goes beyond the countries situated in this geographic region. In fact, the results are transferrable to any region as long as the patterns of resistance are the same.

Rescue Therapy for Helicobacter pylori Infection 2012

Helicobacter pylori infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After 30 years of experience in H. pylori treatment, however, the ideal regimen to treat this infection has still to be found. Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face treatment failures. In designing a treatment strategy, we should not only focus on the results of primary therapy alone but also on the final-overall-eradication rate. The choice of a "rescue" treatment depends on which treatment is used initially. If a first-line clarithromycin-based regimen was used, a second-line metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third-line "rescue" option. Alternatively, it has recently been suggested that levofloxacin-based "rescue" therapy constitutes an encouraging 2nd-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, quadruple regimen may be reserved as a 3rd-line "rescue" option. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several "rescue" therapies are consecutively given.

Efficacy of levofloxacin and rifaximin based quadruple therapy in Helicobacter pylori associated gastroduodenal disease: a double-blind, randomized controlled trial

The aim of this study was to evaluate the efficacy of levofloxacin and rifaximin based quadruple regimen as first-line treatment for Helicobacter pylori infection. A prospectively randomized, double-blinded, parallel group, comparative study was performed. Three hundred consecutive H. pylori positive patients were randomized to receive: omeprazole, amoxicillin, clarithromycin (OAC); omeprazole, amoxicillin, levofloxacin (OAL); and omeprazole, amoxicillin, levofloxacin, rifaximin (OAL-R). The eradication rates in the intention to treat (ITT) and per protocol (PP) analyses were: OAC, 77.8% and 85.6%; OAL, 65.3% and 73.6%; and OAL-R, 74.5% and 80.2%. The eradication rate achieved with OAC was higher than with OAL on the ITT (P = 0.05) and PP analysis (P = 0.04). OAL-R regimen was not inferior to OAC. The frequency of moderate to severe adverse effects was significantly higher in OAC treatment group. Especially, diarrhea was most common complaint, and there was a significantly low rate of moderate to severe diarrhea with the rifaximin containing regimen. In conclusion, the levofloxacin and rifaximin based regimen comes up to the standard triple therapy, but has a limited efficacy in a Korean cohort. The rifaximin containing regimen has a very high safety profile for H. pylori eradication therapy.

Multicenter survey of routine determinations of resistance of Helicobacter pylori to antimicrobials over the last 20 years (1990 to 2009) in Belgium

We analyzed the rates of antimicrobial resistance of Helicobacter pylori strains isolated from patients from 1990 to 2009 and identified risk factors associated with resistance. Gastric biopsy specimens were collected from several digestive disease centers in Brussels, Belgium. We routinely performed antimicrobial susceptibility testing for clarithromycin (CLR), metronidazole, amoxicillin, tetracycline, and ciprofloxacin. Evaluable susceptibility testing was obtained for 9,430 strains isolated from patients who were not previously treated for Helicobacter pylori infection (1,527 isolates from children and 7,903 from adults) and 1,371 strains from patients who were previously treated (162 isolates from children and 1,209 from adults). No resistance to amoxicillin was observed, and tetracycline resistance was very rare (<0.01%). Primary metronidazole resistance remained stable over the years, with significantly lower rates for isolates from children (23.4%) than for isolates from adults (30.6%). Ciprofloxacin resistance remained rare in children, while it increased significantly over the last years in adults. Primary clarithromycin resistance increased significantly, reaching peaks in 2000 for children (16.9%) and in 2003 for adults (23.7%). A subsequent decrease of resistance rates down to 10% in both groups corresponded to a parallel decrease in macrolide consumption during the same period. Multivariate logistic regression revealed that female gender, age of the patient of 40 to 64 years, ethnic background, the number of previously unsuccessful eradication attempts, and the different time periods studied were independent risk factors of resistance to clarithromycin, metronidazole, and ciprofloxacin. Our study highlights the need to update local epidemiological data. Thus, the empirical CLR-based triple therapy proposed by the Maastricht III consensus report remains currently applicable to our population.

Age-dependent eradication of Helicobacter pylori in Japanese patients

AIM: To determine the general risk factors affecting the failure rate of first-line eradication therapy in Japanese patients with Helicobacter pylori (H. pylori) infection.

METHODS: The present study enrolled 253 patients who had an H. pylori infection, underwent gastro-endoscopy, and were treated with H. pylori eradication therapy. Eradication therapy consisted of 30 mg lansoprazole plus 750 mg amoxicillin and 400 mg clarithromycin twice daily for 7 d. All of the patients underwent a ¹³C urea breath test at least 1 mo after the completion of eradication therapy. The current study investigated the independent factors associated with successful H. pylori eradication using a multiple logistic regression analysis.

RESULTS: The overall success rate in the patients was 85.8%. Among the general factors examined in the multivariate analyses, only having an age less than 50 years was found to be significantly associated with a poor response to H. pylori eradication. Moreover, side effects were the only clinical factors in the patients who were under 50 years of age that significantly influenced the poor response to H. pylori eradication.

CONCLUSION: H. pylori-positive elderly patients should undergo eradication therapy. In addition, it is necessary to improve H. pylori eradication therapy in younger patients.

First-line eradication of Helicobacter pylori: Are the standard triple therapies obsolete? A different perspective

Studies concerning the eradication of Helicobacter pylori have resulted in a proliferation of meta-analyses. To date, there are 303 meta-analyses cited in PubMed, 113 dealing with the therapy of the infection. A chronological analysis of the results of meta-analyses performed between 1998 and 2010 shows that first-line standard triple therapies achieved eradication rates on an intention-to-treat basis of around 80%; prolonging treatment to 14, but not 10 d should improve the results. The proton pump inhibitors have a similar efficiency, and giving a double dose is more efficient than the standard doses of these drugs. Triple and quadruple therapies proved to be equivalent. Based on meta-analytical data, the decrease in efficiency over time cannot be substantiated: eradication rates < 80% followed from the introduction of triple therapies. As alternatives, ranitidine bismuth citrate-, levofloxacin- or furazolidone-based therapies were shown to obtain the same eradication rates as standard triple regimens. Sequential therapies and quadruple non-bismuth-based therapies were superior to standard triple therapies but their use is limited to certain countries. In the author’s opinion, and from a meta-analytical viewpoint, standard triple therapies cannot yet be considered obsolete. Furthermore, non-inferiority trials are proposed for the future, including assessment of local contemporary antimicrobial resistance profiles and the CagA and CYP2C19 status of the enrolled patients.

Invasion and multiplication of Helicobacter pylori in gastric epithelial cells and implications for antibiotic resistance

Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects more than 50% of the human population and can cause gastritis, peptic ulcer, or gastric malignancies. It is generally viewed as an extracellular microorganism. In a gentamicin protection assay on AGS or MKN45 cells, H. pylori could invade the epithelial cells and multiply within double-layer vesicles either on the plasma membrane or in the cytoplasm. A 5-fold increase in the number of bacteria was recultured from the infected cells at 12 h, compared with the number of invading cells at 2.5 h postinfection. The autophagic vesicles induced by H. pylori are the sites of replication and also of the degradation of the replicating bacteria after fusion with lysosomes. Many H. pylori bacteria in coccoid form associated with the plasma membrane can be released into culture. Only cell-penetrating antibiotics can enhance the intracellular killing of the replicating bacteria. The multiplication of H. pylori within cells provides a niche for its resistance to antibacterial therapy and has a significant impact on its biological life cycle.

Second-line rescue therapy of helicobacter pylori infection

Helicobacter pylori infection is the main known cause of gastritis, gastroduodenal ulcer disease and gastric cancer. After more than 20 years of experience in H. pylori treatment, however, the ideal regimen to treat this infection has still to be found. Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final (overall) eradication rate. The choice of a 'rescue' treatment depends on which treatment is used initially. If a first-line clarithromycin-based regimen was used, a second-line metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third-line 'rescue' option. Alternatively, it has recently been suggested that levofloxacin-based 'rescue' therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, quadruple regimen may be reserved as a third-line 'rescue' option. Finally, rifabutin-based 'rescue' therapy constitutes an encouraging empirical fourth-line strategy after multiple previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several 'rescue' therapies are consecutively given. Therefore, the attitude in H. pylori eradication therapy failure, even after two or more unsuccessful attempts, should be to fight and not to surrender.

“Rescue” regimens after Helicobacter pylori treatment failure

Helicobacter pylori (H pylori) infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After more than 20 years of experience in H pylori treatment, in my opinion, the ideal regimen to treat this infection is still to be found. Currently, apart from having to know first-line eradication regimens well, we must also be prepared to face treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final (overall) eradication rate. The choice of a “rescue” treatment depends on which treatment is used initially. If a clarithromycin-based regimen was used initially, a subsequent metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third “rescue” option. Alternatively, it has recently been suggested that levofloxacin-based rescue therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, a quadruple regimen may be reserved as a third-line rescue option. Finally, rifabutin-based rescue therapy constitutes an encouraging empirical fourth-line strategy after multiple previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin. Even after two consecutive failures, several studies have demonstrated that H pylori eradication can finally be achieved in almost all patients if several rescue therapies are consecutively given. Therefore, the attitude in H pylori eradication therapy failure, even after two or more unsuccessful attempts, should be to fight and not to surrender.

Treatment of Helicobacter pylori in surgical practice: A randomised trial of triple versus quadruple therapy in a rural district general hospital

AIM: To compare a lansoprazole-based triple versus quadruple therapy for Helicobacter pylori (H pylori) eradication with emphasis on side effect profile, patient compliance and eradication rate at a rural district general hospital in Wales, United Kingdom.

METHODS: One hundred one patients with H pylori infection were included in the study. Patients were randomised to receive triple therapy comprising of lansoprazole 30 mg, amoxycillin 1 g, clarithromycin 500 mg, all b.d. (LAC), or quadruple therapy comprising of lansoprazole 30 mg b.d., metronidazole 500 mg t.d.s., bismuth subcitrate 240 mg b.d., and tetracycline chloride 500 mg q.d.s. (LMBT). Cure was defined as a negative ¹³C urea breath test 2 mo after treatment.

RESULTS: Seven patients were withdrawn after randomisation. Fifty patients were assigned to LAC group and 44 to LMBT group. The intention-to-treat cure rates were 92% and 91%, whereas the per-protocol cure rates were 92% and 97%, respectively. Side effects were common, with 56% experiencing moderate to severe symptoms in the LAC group and 59% in the LMBT group. Symptoms of vomiting, diarrhoea and black stools were significantly more common in the LMBT group. Patient compliance was 100% for triple therapy and 86% for quadruple therapy (P < 0.01). One-third of patients in both groups were still taking acid-reducing medications at six-month follow-up.

CONCLUSION: One-week triple and quadruple therapies have similar intention-to-treat eradication rates. Certain side effects are more common with quadruple therapy, which can compromise patient compliance. Patient education or modifications to the regimen are alternative options to improve compliance of the quadruple regimen.

First-line eradication therapy for Helicobacter pylori in primary health care based on antibiotic resistance: results of three eradication regimens

AIM

To determine the efficacy of three Helicobacter pylori eradication regimens and factors affecting the eradication results in Finland.

METHODS

A total of 342 H. pylori-positive adult patients from primary health care referred for gastroscopy at 23 centres in different parts of Finland were randomized to receive either (i) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and metronidazole 400 mg t.d.s. (LAM), (ii) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC), or (iii) ranitidine bismuth citrate 400 mg b.d., metronidazole 400 mg t.d.s. and tetracycline 500 mg q.d.s. (RMT). A (13)C-urea breath test was performed 4 weeks after therapy.

RESULTS

The eradication result could be assessed in 329 cases. Intention-to-treat cure rates of LAM, LAC, and RMT were 78, 91 and 81%. The difference was significant between LAM and LAC (P = 0.01) and between LAC and RMT (P = 0.04). The eradication rates in cases with metronidazole-susceptible vs. -resistant isolates were for LAM 93% vs. 53% (P = 0.00001), for LAC 95% vs. 84%, and for RMT 91% vs. 67% (P = 0.002). Previous antibiotic use, smoking, and coffee drinking reduced the efficacy of therapy.

CONCLUSIONS

In unselected patients in primary health care, LAC was the most effective first-line eradication.

Novel bismuth-metronidazole-tetracycline triple-layer tablet for treatment of Helicobacter pylori

BACKGROUND

Current anti-Helicobacter pylori treatment regimens are costly and because of the increasing antibiotic resistance, are becoming ineffective.

AIM

To evaluate a triple-layer tablet containing 100 mg bismuth subcitrate, 250 mg metronidazole, and 250 mg tetracycline in a single triple-layer tablet.

METHODS

H. pylori-infected adult patients received bismuth-metronidazole-tetracycline (two tablets, t.d.s.) and ranitidine (300 mg) once daily for 14 days. Efficacy was determined using 13C-urea breath testing.

RESULTS

Thirty-three of 35 enrolled patients were available for evaluation; using the protocol-specified modified intention-to-treat analysis, five failed treatment, two were lost to follow-up (cure rate per-protocol = 85.7%, intention-to-treat = 78.7%). The cure rate among metronidazole-susceptible strains was 100% (22 of 22) (95% confidence interval 84-100%) compared with 55% (five of nine intention-to-treat) (95% confidence interval 21-86%) among metronidazole-resistant strains. In four cases, therapy was truncated at 4-7 days because of side-effects; yet the treatment was effective in three. The three metronidazole-susceptible but clarithromycin-resistant infections were cured.

CONCLUSION

This novel triple-layer tablet combination therapy was effective in all patients with metronidazole-susceptible H. pylori and many of those with resistant organisms. A greater degree of acid suppression may further improve effectiveness.

The importance of the level of metronidazole resistance for the success of Helicobacter pylori eradication

AIMS

To evaluate the role of antibiotic susceptibility for the treatment outcome of proton pump inhibitor-dependent and independent Helicobacter pylori eradication regimens.

METHODS

In a placebo-controlled clinical study of peptic ulcer patients with H. pylori infection, patients were randomized to receive lansoprazole, clarithromycin and tinidazole twice-daily, clarithromycin and tinidazole once-daily with lansoprazole or with placebo. Helicobacter pylori status was assessed by culture and antibiotic susceptibility by E-test minimal inhibitory concentration (MIC) in 205 clinical isolates.

RESULTS

Primary resistance to clarithromycin and metronidazole was 1 and 76%, respectively. In metronidazole susceptible strains eradication rates were similar at > 90% for all treatment groups (P = 0.49). With low-level metronidazole resistance (4 microg/mL < MIC < 256 microg/mL), eradication rates were similar at >75% (P = 0.80). The major difference was found at high-level metronidazole resistance (MIC >or= 256 microg/mL) with 95%, 58% and 21% eradication in the lansoprazole, clarithromycin and tinidazole twice-daily, lansoprazole, clarithromycin and tinidazole once-daily and placebo, clarithromycin and tinidazole once-daily groups, respectively (P < 0.001).

CONCLUSION

In the absence of antibiotic resistance, a once-daily therapy of only clarithromycin and tinidazole can achieve a high rate of H. pylori eradication. Such a combination could offer a simpler and cheaper treatment option for developing countries. The standard, twice-daily proton pump inhibitor-based triple therapy was shown to be efficient in H. pylori eradication even in the presence of high-level metronidazole resistance.

Diagnostic methods for Helicobacter pylori detection and eradication

Helicobacter pylori is the principal cause of peptic ulcer disease and an important risk factor for the development of gastric cancer. The efficacy of 1 week triple therapies, which often have eradication rates of>90%, is undermined by poor patient compliance and bacterial antimicrobial resistance. The development of new anti-H. pylori therapies presents enormous challenges to clinical pharmacologists, not only in the identification of novel targets, but also in ensuring adequate drug delivery to the unique gastric mucus niche of H. pylori. Animal models of H. pylori infection have been developed but their clinical validity has yet to be established. Vaccination, to prevent or treat infection, has been demonstrated in animal models, but human studies have not been so encouraging.

A rational approach to uninvestigated dyspepsia in primary care: review of the literature

In this paper the rationale and limitations of the four most important approach strategies to dyspepsia in primary care (empiric treatment, prompt endoscopy, "test-and-scope", and "test-and-treat") are analysed. It is concluded that in the absence of alarm symptoms, a "test-and-treat" approach is currently the most rational approach provided that three conditions are met: (1) a highly accurate test should be used, (2) the prevalence of Helicobacter pylori in the population should not be too low, and (3) an effective anti-H pylori regimen should be prescribed taking sufficient time to instruct and motivate the patient.

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.

Analysis of rdxA and involvement of additional genes encoding NAD(P)H flavin oxidoreductase (FrxA) and ferredoxin-like protein (FdxB) in metronidazole resistance of Helicobacter pylori

Metronidazole (Mtz) is a critical ingredient of modern multidrug therapies for Helicobacter pylori infection. Mtz resistance reduces the effectiveness of these combinations. Although null mutations in a rdxA gene that encodes oxygen-insensitive NAD(P)H nitroreductase was reported in Mtz-resistant H. pylori, an intact rdxA gene has also been reported in Mtz-resistant H. pylori, suggesting that additional Mtz resistance mechanisms exist in H. pylori. We explored the nature of Mtz resistance among 544 clinical H. pylori isolates to clarify the role of rdxA inactivation in Mtz resistance and to identify another gene(s) responsible for Mtz resistance in H. pylori. Mtz resistance was present in 33% (181 of 544) of the clinical isolates. There was marked heterogeneity of resistance, with Mtz MICs ranging from 8 to >/=256 microg/ml. rdxA inactivation resulted in Mtz MICs of up to 32 microg/ml for 6 Mtz-sensitive H. pylori strains and 128 microg/ml for one Mtz-sensitive strain. Single or dual (with rdxA) inactivation of genes that encode ferredoxin-like protein (designated fdxB) and NAD(P)H flavin oxidoreductase (frxA) also increased the MICs of Mtz for sensitive and resistant strains with low to moderate levels of Mtz resistance. fdxB inactivation resulted in a lower level of resistance than that from rdxA inactivation, whereas frxA inactivation resulted in MICs similar to those seen with rdxA inactivation. Further evidence for involvement of the frxA gene in Mtz resistance included the finding of a naturally inactivated frxA but an intact rdxA in an Mtz-resistant strain, complementation of Mtz sensitivity from an Mtz-sensitive strain to an Mtz-resistant strain or vice versa by use of naturally inactivated or functional frxA genes, respectively, and transformation of an Mtz-resistant Escherichia coli strain to an Mtz sensitive strain by a naturally functional frxA gene but not an inactivated frxA gene. These results are consistent with the hypothesis that null mutations in fdxB, frxA, or rdxA may be involved in Mtz resistance.