Eradication of Helicobacter pylori in children in Vietnam in relation to antibiotic resistance

Background: Low Helicobacter pylori eradication rates are common in pediatric trials especially in developing countries. The aim of the study was to investigate the role of antibiotic resistance, drug dosage, and administration frequency on treatment outcome for children in Vietnam. Materials and Methods: Antibiotics resistance of H. pylori was analyzed by the Etest in 222 pretreatment isolates from children 3–15 years of age who were originally recruited in a randomized trial with two treatment regiments: lansoprazole with amoxicillin and either clarithromycin (LAC) or metronidazole (LAM) in two weight groups with once‐ or twice‐daily administration. The study design was an observational study embedded in a randomized trial. Results: The overall resistance to clarithromycin, metronidazole, and amoxicillin was 50.9%, 65.3%, and 0.5%, respectively. In LAC, eradication was linked to the strains being susceptible to clarithromycin (78.2% vs 29.3%, p = .0001). Twice‐daily dosage of proton‐pump inhibitor (PPI) and clarithromycin was more effective for eradication than once‐daily dosage for resistant strains (50.0% vs 14.7%, p = .004) and tended to be so also for sensitive strains (87.5% vs 65.2%, p = .051). Exact antibiotic dose per body weight resulted in more eradication for resistant strains (45.3% vs 8.0%, p = .006). These differences were less pronounced for the LAM regimen, with twice‐daily PPI versus once daily for resistant strains resulting in 69.2% and 50.0% eradication (p = .096), respectively. Conclusions: Helicobacter pylori clarithromycin resistance was unexpectedly high in young children in Vietnam. Clarithromycin resistance was an important cause for eradication treatment failure. Twice‐daily administration and exact antibiotic dosing resulted in more eradicated infections when the strains were antibiotic resistant, which has implications for the study design in pediatric H. pylori eradication trials.     

The evolution of Helicobacter pylori antibiotics resistance over 10 years in Beijing, China

Objectives: To evaluate Helicobacter pylori antibiotics resistance evolution from 2000 to 2009 to amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin and moxifloxacin in Beijing, China. Methods: A total of 374 H. pylori strains isolated from 374 subjects who had undergone upper gastrointestinal endoscopy from 2000 to 2009 were collected and examined by E‐test method for antibiotics susceptibility. Results: The average antibiotics resistance rates were 0.3% (amoxicillin), 37.2% (clarithromycin), 63.9% (metronidazole), 1.2% (tetracycline), 50.3% (levofloxacin) and 61.9% (moxifloxacin). Overall resistance to clarithromycin, metronidazole, and fluoroquinolone increased annually (from 14.8 to 65.4%, 38.9 to 78.8%, and 27.1 to 63.5%, in 2000 or 2006–2007 to 2009, respectively). The secondary resistance rates were much higher than primary rates to these antibiotics, which also increased annually in recent 10 years. Conclusions: The trend of clarithromycin, metronidazole, and fluoroquinolone resistance of H. pylori increased over time and the resistance to amoxicillin and tetracycline was infrequent and stable in Beijing. Clarithromycin, metronidazole, and fluoroquinolone should be used with caution for H. pylori eradication treatment.     

Evaluation of a four-drug, three-antibiotic, nonbismuth-containing "concomitant" therapy as first-line Helicobacter pylori eradication regimen in Greece

Background: The eradication rates of Helicobacter pylori (H. pylori) with standard treatments are decreasing worldwide as in Greece. Studies with new antibiotic combinations are needed to find better methods of eradication. Therefore, the aim of this study was to evaluate efficacy and tolerability of a 10‐day, four‐drug, three‐antibiotic, nonbismuth–containing concomitant regimen. Materials and Methods: This is a prospective, open‐label, multicenter study that included 131 patients infected with H. pylori. All patients were diagnosed with peptic ulcer disease or nonulcer dyspepsia by endoscopy. H. pylori infection was established by at least two positive tests among rapid urease test, gastric histology, and ¹³C‐urea breath test. For 10 days, all patients received esomeprazole 40 mg, amoxycillin 1000 mg, clarithromycin 500 mg, and metronidazole 500 mg, all b.d. eradication was assessed with ¹³C urea breath test 8 weeks after the start of treatment. Intention‐to‐treat and per‐protocol eradication rates were determined. Results: One hundred and twenty‐seven of the 131 patients completed the study. At intention‐to‐treat analysis, the eradication rate was 91.6% (95% confidence interval (CI), 85.5–95.7%). For the per‐protocol analysis, the eradication rate was 94.5% (95% CI, 89–97.8%). Adverse events were noted in 42 of 131 (32.1%); drug compliance was excellent with 96.9% of the patients taking more than 90% of the prescribed medication. Conclusion: A 10‐day concomitant regimen appears to be an effective, safe, and well‐tolerated treatment option for first‐line H. pylori eradication in Greece.     

The relationship between consumption of antimicrobial agents and the prevalence of primary Helicobacter pylori resistance

Background. Primary and acquired resistance to the antimicrobial agents is a primary reason for the failure of Helicobacter pylori eradication therapies. We assessed the primary antibiotic resistance rates of H. pylori to three different antibiotics and its relationship due to the annual antibiotic consumption in Japan during the period prior to approval of anti‐H. pylori therapy in Japan. Materials and Methods. Antibiotic susceptibility was tested using the agar dilution method for clarithromycin, amoxicillin and metronidazole. Isolates were considered resistant when the MIC value was > 8 mg/l for metronidazole, > 1 mg/l for clarithromycin and < 0.5 mg/l for amoxicillin. Results. Helicobacter pylori isolates were obtained from 593 Japanese patients from 1995 to 2000. Primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin was found in 11%, 9% and 0.3% strains, respectively. The proportion with clarithromycin resistance significantly increased from 7% in 1997–98 to 15.2% in 1999–2000 (p = .003). During the same period the metronidazole resistance rate also increased from 6.6% in 1997–98 to 12% in 1999–2000 (p = .02). The prevalence of clarithromycin and metronidazole was related to the annual consumption of these antimicrobial agents. Conclusion. Resistance rates for both clarithromycin and metronidazole appear to reflect the annual consumption of these agents. The high rate of clarithromycin resistance in Japan suggests that the effectiveness of clarithromycin‐based therapies may be compromised in the near future.     

Impact of furazolidone-based quadruple therapy for eradication of Helicobacter pylori after previous treatment failures

Background. One week of quadruple therapy including metronidazole is recommended for Helicobacter pylori treatment failures after first line therapy regardless of resistance status. This study investigated whether a quadruple regimen containing furazolidone could be effective as a third‐line (salvage) therapy. Methods. All patients with previous H. pylori treatment failure after a clarithromycin‐metronidazole ± amoxicillin combination plus acid suppression were given lansoprazole 30 mg twice a day (bid), tripotassiumdicitratobismuthate 240 mg bid, tetracycline 1 g bid, metronidazole 400 mg (PPI‐B‐T‐M) three times a day (tid) for 1 week. In the case of treatment failure with this second‐line therapy, the same regimen was applied for 1 week except for using furazolidone 200 mg bid (PPI‐B‐T‐F) instead of metronidazole (sequential study design). Results. Eighteen consecutive patients were treated with PPI‐B‐T‐M. Eleven of those 18 remained H. pylori positive (38.9% cured). Pretherapeutic metronidazole resistance was associated with a lower probability of eradication success (10% vs. 75%, p= .04). Ten of these 11 patients agreed to be retreated by PPI‐B‐T‐F. Final cure of H. pylori with PPI‐B‐T‐F was achieved in 9/10 patients (90%) nonresponsive to PPI‐B‐T‐M. Conclusions. In the presence of metronidazole resistance, PPI‐B‐T‐M as a recommended second‐line therapy by the Maastricht consensus conference achieved unacceptable low cure rates in our metronidazole pretreated population. In this population, metronidazole based second‐line quadruple therapy may be best suited in case of a metronidazole‐free first line‐regimen (e.g. PPI‐clarithromycin‐amoxicillin) or a low prevalence of metronidazole resistance. Furazolidone in the PPI‐B‐T‐F combination does not have a cross‐resistance potential to metronidazole and is a promising salvage option after a failed PPI‐B‐T‐M regimen.     

Annual Change of Primary Resistance to Clarithromycin among Helicobacter pylori Isolates from 1996 through 2008 in Japan

Background: Recent studies have shown that the combination of proton pump inhibitor, amoxicillin and clarithromycin is one of the best choices for Helicobacter pylori eradication therapy. However, increasing number of cases of H. pylori infection showing resistance to clarithromycin therapy has been reported and this is currently the main cause of eradication failure. We investigated the annual changes of the antimicrobial susceptibility to clarithromycin, amoxicillin and minocycline during a period of 12 years in Japan. Methods: This study comprised 3521 patients (mean age (SD), 55.4 (13.7) years‐old, 2467 males and 1054 females) positive for H. pylori as assessed by microaerobic bacterial culture from 1996 through 2008. All patients were previously untreated for H. pylori and were enrolled in the study to assess primary resistance to the three antibiotics. Results: The overall primary resistance to clarithromycin, amoxicillin and minocycline were 16.4%, (577/3521), 0.03% (1/3521) and 0.06% (2/3521), respectively. From1996 through 2004, the resistance rate to clarithromycin increased gradually to approximately 30% and then it remained without marked fluctuation since 2004. Analysis by gender showed a significant increase (p < .0001) in resistance rate to clarithromycin among females (217/1057, 20.6%) compared to males (360/2467, 14.6%). Analysis by age, disclosed significantly (p < .0001) higher resistance rate to clarithromycin in patients of more than 65‐years‐old compared to the younger population. Conclusions: The resistance rate of H. pylori infection to clarithromycin in Japan has increased gradually to approximately 30% from 1996 through 2004, and remained unchanged since 2004. Elderly and females were at high risk of having resistance to clarithromycin. Our results suggested that the level of clarithromycin resistance in Japan has now risen to the point where it should no longer be used as empiric therapy.     

Antibiotic resistance of Helicobacter pylori in Mazandaran, North of Iran

Background: The aim of this study was to investigate the prevalence of resistances in Helicobacter pylori against commonly used antibiotics including metronidazole, clarithromycin, amoxicillin, and tetracycline in Iranian patients. Methods: H. pylori isolates were collected from gastric biopsies from patients referred for upper gastrointestinal endoscopy at Tooba Medical Center, Sari, Iran, from 2007 to 2010. None of them had been using antibiotics for at least 8 months. H. pylori was identified based on morphological shape and positive biochemical tests for catalase, oxidase, and urease activity. Antibiotic resistance for metronidazole, clarithromycin, amoxicillin, and tetracycline was investigated by using epsilometer test. Resistance was defined by minimal inhibitory concentration (MIC) > 0.5 mg/L for amoxicillin (AMX), >4 mg/L for tetracycline (TET), >8 mg/L for metronidazole (MTZ), and >1 mg/L for clarithromycin (CLR). Results: Strains were collected from 132 patients, mean age 45.8 years, 52 (39%) were women. Patients had diverse diagnoses: gastritis 42 (31.8%), duodenal ulcer 45 (34%), gastric cancer 15 (11.3%), or gastric ulcer 30 (22.7%). The prevalences of resistance of H. pylori strains isolated from the patients were 73.4% for metronidazole, 30% for clarithromycin, 6.8% for amoxicillin, and 9% for tetracycline. Twenty‐eight (21.2%) were double resistant to MTZ‐CLR, 16 (12.1%) showed triple resistance to MTZ‐CLR‐AMX, and 8 (6%) were resistant to all four tested antibiotics (MTZ‐CLR‐AMX‐TET). No associations were detected between multiple resistant strains and clinical manifestations (p > .05). Conclusions: The prevalence of H. pylori antibiotic resistance to metronidazole and clarithromycin was high in Iran consistent with the reported low success rates for H. pylori treatment in this country.     

A comparison between sequential therapy and a modified bismuth-based quadruple therapy for Helicobacter pylori eradication in Iran: a randomized clinical trial

Background: Sequential regimens have been recently reported to be superior to the standard triple therapies in Helicobacter pylori eradication, but most of these studies were performed in Europe and data from developing countries are lacking. So we designed a study to compare a sequential regimen with a bismuth‐based quadruple therapy that contains a short course of furazolidone, in Iran. Methods: Two hundred and ninety‐six patients with duodenal ulcer and naïve H. pylori infection were randomized into two groups: 148 patients received (PAB‐F) pantoprazole (40 mg‐bid), amoxicillin (1 g‐bid), and bismuth subcitrate (240 mg‐bid) for 2 weeks and furazolidone (200 mg‐bid) just during the first week. And 148 patients received (PA‐CT) pantoprazole (40 mg‐bid) for 10 days, amoxicillin (1 g‐bid) for the first 5 days, and clarithromycin (500 mg‐bid) plus tinidazole (500 mg‐bid) just during the second 5 days. C¹⁴‐urea breath test was performed 8 weeks after the treatment. Results: Two hundred and sixty‐one patients completed the study (137 patients in the PA‐CT and 124 in the PAB‐F group). The results were not statistically different between the two groups in the eradication rates and the severity of side effects. The intention to treat eradication rate was 80.4% in the PAB‐F group and 83.7% in the PA‐CT group. Per‐protocol eradication rates were 88.7% and 89.1%, respectively. Conclusion: Because the two regimens showed acceptable and similar abilities in H. pylori eradication and because of much higher cost of clarithromycin in Iran, the furazolidone containing regimen seems to be superior. Further modifications of sequential therapies are needed to make them ideal regimens in developing countries.     

Sequential metronidazole-furazolidone or clarithromycin-furazolidone compared to clarithromycin-based quadruple regimens for the eradication of Helicobacter pylori in peptic ulcer disease: a double-blind randomized controlled trial

Background: Furazolidone is a much cheaper drug with a very low resistance against Helicobacter pylori compared to clarithromycin. We aim to evaluate safety and efficacy of a sequential furazolidone‐based regimen versus clarithromycin‐based therapy in H. pylori eradication for ulcer disease. Materials: Patients with proven peptic ulcer or duodenitis were randomized into three groups: OAB‐M‐F; metronidazole (M) (500 mg bid) for the first 5 days, followed by furazolidone (F) (200 mg bid) for the second 5 days; OAC‐P; clarithromycin (C) (500 mg bid) for 10 days; and OAB‐C‐F; clarithromycin (500 mg bid) for the first 5 days and furazolidone (200 mg bid) for the second 5 days. All groups received omeprazole (O) (20 mg bid) and amoxicillin (A) (1 g bid). Groups OAB‐M‐F and OAB‐C‐F were also given bismuth subcitrate (B) (240 mg bid), whereas a placebo (P) was given to group OAC‐P. Adverse events were scored and recorded. Two months after treatment, a C¹³‐urea breath test was performed. Results: Three hundred and ten patients were enrolled and 92 (OAB‐M‐F), 95 (OAC‐P), and 98 (OAB‐C‐F) completed the study. The intention‐to‐treat eradication rates were 78.5% (95% CI = 69–85), 81.1% (95% CI = 73–88), and 82% (95% CI = 74–89), and per‐protocol eradication rates were 91.3% (95% CI = 83–96), 90.4% (95% CI = 82–95), and 88.7% (95% CI = 81–94), for group OAB‐M‐F, OAC‐P, and OAB‐C‐F, respectively. Eradication rate differences did not reach statistical significance. The most common adverse event, bad taste, occurred in all groups, but more frequently in groups OAC‐P (34%) and OAB‐C‐F (32%), than OAB‐M‐F (14%) (p < .05). Adverse symptoms score were 0.88 ± 2.05 in group OAB‐M‐F, 1.15 ± 1.40 in group OAC‐P, and 1.87 ± 1.62 in group OAB‐C‐F. Conclusion: Furazolidone can replace clarithromycin in H. pylori eradication regimens because of lack of development of resistance and very low cost.     

Systematic review and meta-analysis: proton pump inhibitor vs. ranitidine bismuth citrate plus two antibiotics in Helicobacter pylori eradication

OBJECTIVE: To systematically review the Helicobacter pylori eradication efficacy with ranitidine bismuth citrate (RBC) and two antibiotics, and to conduct a meta-analysis of randomized clinical trials comparing the efficacy of proton pump inhibitor (PPI) vs. RBC with two antibiotics for 1 week. METHODS: Selection of studies: Studies evaluating RBC plus two antibiotics were considered. For the meta-analysis, randomized controlled trials comparing PPI vs. RBC plus two antibiotics for 1 week were included. Search strategy: Electronic and manual bibliographical searches. Assessment of study quality and data extraction: Independently done by two reviewers. Data synthesis: 'Intention-to-treat' eradication rate. Meta-analysis was performed, combining the odds ratios (OR) of the individual studies. Subanalysis: Depending on the type of antibiotics and the quality of the studies. RESULTS: Mean H. pylori eradication with 7-day RBC-clarithromycin-amoxicillin, RBC-clarithromycin-nitroimidazole, and RBC-amoxicillin-nitroimidazole was 83%, 86%, and 71%, respectively. The meta-analysis showed comparable efficacy with RBC and PPI when they were combined with clarithromycin and amoxicillin (OR = 1.11; 95% CI = 0.88-1.40), or with amoxicillin and metronidazole (OR = 0.92; 95%CI = 0.60-1.41). However, when comparing PPI vs. RBC plus clarithromycin and a nitroimidazole, higher cure rates with RBC than with PPI were demonstrated (OR = 1.65; 95% CI = 1.15-2.37). CONCLUSION: The efficacy of RBC and PPI-based triple regimens were comparable when using the clarithromycin-amoxicillin or the amoxicillin-metronidazole combination. However, RBC seems to have a higher efficacy than PPI when clarithromycin and a nitroimidazole are the antibiotics prescribed. Therefore, if one prefers to use the clarithromycin-nitroimidazole regimen, RBC should be used instead of a PPI.     

Low efficacy of clarithromycin including sequential regimens for Helicobacter pylori infection

Background: Sequential treatment for Helicobacter pylori (H. pylori) appears to achieve a better eradication rate than triple therapy. However, most of the data have been reported from the Italy, and studies from different population are needed before it is recommended in clinical practice. The present study aimed to assess and compare the efficacy of two separate clarithromycin including sequential regimens in Turkey which is well known with high clarithromycin and metronidazole resistance to H. pylori. Methods: Consecutive H. pylori ‐positive patients with non‐ulcer dyspepsia were randomly allocated to one of the two sequential regimens; the first group was given lansoprazole 30 mg b.i.d. plus amoxicillin 1 g b.i.d. for the first week, followed by lansoprazole 30 mg b.i.d., clarithromycin 500 mg b.i.d., and metronidazole 500 mg t.i.d. for the second week (LA‐CM). The second arm was given the same regimen but tetracycline500 g q.i.d. instead of metronidazole (LA‐CT). H. pylori was detected with urea breath test (UBT) and histology before enrollment. UBT was repeated at 6th weeks after treatment. Results: A total of 200 patients were enrolled in groups and 179 of them completed their protocols. The cumulative per protocol (“PP”) and intention‐to‐treat (“ITT”) eradication rates were 74.3% and 66.5% in all patients, respectively. Both “PP” (78.2% vs 70.1%) and “ITT” (72% vs 61%) eradication rates were better in LA‐CT group than LA‐CM group, but the differences were not statistically significant (p > .05). Both regimens were well tolerated, and the incidence of adverse effects was comparable. Conclusion: Two weeks clarithromycin including sequential regimens with metronidazole or tetracycline were not achieved acceptable eradication rates in Turkey.     

Amoxicillin resistance in Helicobacter pylori: studies from Tokyo, Japan from 1985 to 2003

BACKGROUND: Previous reports revealed no resistant strains of amoxicillin (AMPC), which is usually used in eradication therapy for H. pylori infection. However, the frequency and evolution of natural AMPC-resistant strains in the Japanese population remains unknown. AIM: To assess the prevalence of H. pylori resistance against AMPC in the Tokyo area, a collection of 648 H. pylori strains isolated from patients with GI diseases from 1985 to 2003 was tested for their sensitivity to AMPC. METHODS: The susceptibility of the strains was assessed by determination of the minimal inhibitory concentration (MIC) using the E-test and/or the Dry-plate method. The susceptibility breakpoints of AMPC for H. pylori were: sensitive (AMPC-S); MIC < 0.04 microg/ml, intermittent resistance (AMPC-I); 0.04-1, resistant (AMPC-R); > 1. RESULTS: No AMPC-R strains were detected in the strains isolated between 1985 and 1996, while the rate of resistance was determined to be 1.1%, 2.1%, 5.4%, 5.6%, 0%, 8.8%, and 1.5% every year, respectively, from 1997 to 2003. The percentage of AMPC-I strains increased from 2000 to 2003. The total eradication rate of H. pylori in the patients who received triple therapy containing AMPC was 81.4% (214/263). Classified as above, the rates of AMPC-S, AMPC-I, and AMPC-R were 84.6%, 77.8%, 25%, respectively. CONCLUSION: H. pylori resistance to AMPC is still rare in Japan, although the percentage of AMPC-I strains has increased over the last 4 years. The frequency of isolation of strains showing true resistance to AMPC may increase in the future, along with an increase in the frequency of isolation of AMPC-I strains.     

Analysis of antibiotic susceptibility patterns of Helicobacter pylori isolates from Malaysia

Background: The prevalence of antibiotic resistance varies in geographic areas. The information on the antibiotic susceptibility patterns of Helicobacter pylori (H. pylori) in our local setting is therefore relevant as a guide for the treatment options. Objective: This study was conducted to determine the primary resistance rates among H. pylori isolated from Malaysian patients. Materials and methods: Biopsy samples were obtained from the stomach antrum and corpus of 777 patients from September 2004 until 2007. H. pylori isolated from these patients were then subjected to minimum inhibitory concentration (MICs) determination using E‐test method, against metronidazole, clarithromycin, levofloxacin, ciprofloxacin, amoxicillin, and tetracycline. Results: From 777 patients, 119 were positive for H. pylori where a total of 187 strains were isolated. The resistance rates were noted to be 37.4% (metronidazole), 2.1% (clarithromycin), 1% (levofloxacin and ciprofloxacin), and 0% (amoxicillin and tetracycline). Different resistance profiles were observed among isolates from the antrum and corpus of 13 patients. Resistance to one type of antibiotic was observed in 36.4% of the strains where mono‐resistance to metronidazole was the most common. Resistance to ≥2 antibiotics was noted in 3.3% of isolates. High metronidazole MICs of ≥256 μg/mL were observed among the resistant strains. Conclusions: The resistance rates of the antibiotics used in primary treatment of H. pylori infections in Malaysia are low, and multi‐antibiotic‐resistant strains are uncommon. Infections with mixed populations of metronidazole‐sensitive and ‐resistant strains were also observed. However, the high metronidazole MIC values seen among the metronidazole‐resistant strains are a cause for concern.