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.     

Low efficacy rate of moxifloxacin-containing Helicobacter pylori eradication treatment: in an observational study in a Turkish population

BACKGROUND: Standard triple therapy for Helicobacter pylori has an eradication rate of about 50% in Turkey. It may be due to an increased resistance of H. pylori to antibiotics. Therefore, we aimed to investigate the effectiveness of a new second-generation fluoroquinolone, moxifloxacin-containing triple therapy in H. pylori eradication. MATERIAL AND METHODS: This is an open-label, prospective, single-center, pilot study. We studied 71 dyspeptic patients infected with H. pylori diagnosed by both histology and rapid urease test. Out of 71 dyspeptic patients, 64 had non-ulcer dyspepsia and seven had peptic ulcer. Patients received pantoprazole (40 mg b.i.d.) plus moxifloxacin (400 mg/day) and amoxicillin (1000 mg b.i.d.) for 14 days. Eradication was assessed 4 weeks after completing the therapy by histology and rapid urease test. Per-protocol and intention-to-treat eradication rates were determined. RESULTS: The eradication rate was 42.2% for the intention-to-treat analysis and 47.6% for the per-protocol analysis. Of all patients included in the study, 29.5% had side-effects and only 2.8% of the patients discontinued the treatment because of side-effects. Most of the complications were mild and self-limiting. CONCLUSION: Triple therapy with pantoprazole, moxifloxacin, and amoxicillin for 14 days yielded unacceptably low eradication rates. However, using tests of susceptibility to antibiotics, further studies with larger sample sizes are needed to judge these eradication rates of moxifloxacin containing eradication treatment.     

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.     

Mutations of Helicobacter pylori associated with fluoroquinolone resistance in Korea

Background and Aim: Fluoroquinolone resistance of Helicobacter pylori is known to be dependent on mutations in the QRDR of gyrA. This study was performed to investigate the distribution of gyrA point mutations and to evaluate the impact of the mutations on second‐line H. pylori eradication therapy. Methods: After H. pylori isolation from gastric mucosal specimens, fluoroquinolone resistance was examined using the agar dilution method. DNA sequencing of the QRDR of gyrA was performed in 89 fluoroquinolone‐resistant and 27 fluoroquinolone‐susceptible isolates. Transformation experiments were performed to confirm mutations in the resistant strains. The eradication rates of moxifloxacin‐containing triple therapy were evaluated depending on the resistance of fluoroquinolone. Results: The gyrA mutations were detected in 75.3% (55 of 73 strains) of the primary resistant strains and 100% (16 strains) of the secondary resistant strains. The most common mutations were Asp‐91 (36.0%) and Asn‐87 (33.7%). The MIC values in the transformed strains differed depending on the gyrA mutations, N87, and D91. Six patients with fluoroquinolone‐resistant strains received moxifloxacin‐containing triple therapy as the second‐line therapy, and two of three patients with Asn‐87 mutations (66.7%) failed in the eradication. By contrast, three patients with Asp‐91 mutations had successful eradication treatment. Conclusions: Fluoroquinolone resistance of H. pylori was caused by gyrA Asn‐87 and Asp‐91 point mutations. The Asn‐87 mutation seems to be an important determinant of failure of fluoroquinolone‐containing triple eradication therapy based on eradication results.     

Comparison of two management strategies for Helicobacter pylori treatment: clinical study and cost-effectiveness analysis

BACKGROUND: First-line proton pump inhibitor-based triple and quadruple therapies for Helicobacter pylori eradication present similar levels of efficacy. Cross-over treatment (quadruple following triple failure, and triple following quadruple failure) seems the most sensible approach to treatment failures, but the two strategies -'quadruple first' versus 'triple first'- have not been previously compared. The aims of our study were to assess the usefulness and the cost-effectiveness of the two treatment strategies. MATERIAL AND METHODS: Forty-nine out of 344 patients included in a previous study comparing triple therapy - 7 days of omeprazole, amoxicillin and clarithromycin twice a day - with quadruple therapy - 7 days of omeprazole twice a day, plus tetracycline, metronidazole and bismuth subcitrate three times a day - failed initial treatment and were assigned to cross-over therapy. Cure was determined by urea breath test. A decision analysis was performed to compare the two eradication strategies. RESULTS: Intention to treat cure rates were 46% (10/22 patients; 95% CI 24-68%) for second-line triple therapy and 63% (17/27 patients; 95% CI 42-81%) for second-line quadruple therapy. Per protocol cure rates were 71% and 85%, respectively. Intention to treat cure rates were 87% (95% CI 81-92%) for the 'triple first' versus 86% (95% CI 80-91%) for the 'quadruple first' strategy (p = .87). The 'quadruple first' strategy was more cost-effective. The incremental cost of 'triple first' strategy per person was 19 in the low-cost area and 65 US dollars in the high-cost area. CONCLUSIONS: The effectiveness of 'triple first' and 'quadruple first' strategies is similar, although the latter seems slightly more cost-effective.     

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.     

Does Helicobacter pylori eradication affect symptoms in nonulcer dyspepsia: a 5-year follow-up study

The role of Helicobacter pylori infection in nonulcer dyspepsia remains controversial. To date studies exploring the effect of H. pylori eradication on symptoms have reported conflicting results. Randomised control trials employing validated outcome measures have also been difficult to interpret because of several important issues such as the large placebo response seen in patients with nonulcer dyspepsia and both the natural variability in symptoms and symptom severity with time. The association of symptom improvement with resolution of gastritis has meant that the length of follow up employed in most studies has been insufficient. We report the findings of a randomised placebo controlled trial (n = 100), using a validated symptom questionnaire and 5 year follow up to determine the effect of H. pylori eradication on symptoms in nonulcer dyspepsia. In all 64 that were reviewed at 5 years there was a significant difference between patients who were H. pylori negative and those who remained positive with regard to complete symptom resolution, consumption of relevant medications and peptic ulcer disease development, in favour of active treatment. There was a trend for gradual symptom improvement over time irrespective of H. pylori status, which may reflect the natural history of this condition. For those who remained symptomatic at 5 years, there was no difference in symptom severity based on H. pylori status. The findings of this study support the use of H. pylori eradication in symptomatic patients with nonulcer dyspepsia both to induce symptom resolution and to prevent disease progression.     

Comparison of 7-day and 14-day proton pump inhibitor-containing triple therapy for Helicobacter pylori eradication: neither treatment duration provides acceptable eradication rate in Korea

BACKGROUND AND AIMS: Although triple combination therapy containing a proton pump inhibitor (PPI) and two antibiotics is considered as a standard regimen for the first-line anti-Helicobacter pylori treatment, there are still debates on the ideal duration of treatment. The aim of this study was to compare the efficacies of 7-day and 14-day PPI-containing triple therapy. MATERIALS AND METHODS: This study was performed in a randomized, multicenter, prospective manner. After upper gastrointestinal endoscopy, H. pylori-infected patients with a gastric ulcer and/or a duodenal ulcer were randomly assigned to a PAC7 group (omeprazole 20 mg or equivalent dose of other PPIs, amoxicillin 1000 mg, and clarithromycin 500 mg twice daily for 7 days) or to a PAC14 group (the same regimen as the PAC7 group but for 14 days). H. pylori status was evaluated by (13)C urea breath test 5 weeks after anti-ulcer treatment completion. RESULTS: A total of 598 patients were enrolled; 337 were randomized to the PAC7 group and 261 to the PAC14 group. The two groups were comparable in terms of baseline characteristics. The eradication rates of the PAC7 group were not inferior to those of the PAC14 group in both intention-to-treat analysis (71.2% vs. 75.5%) and per-protocol analysis (83.6% vs. 86.6%). Incidences of adverse events were comparable. CONCLUSIONS: Although the 7-day PPI-containing triple anti-H. pylori therapy is not inferior to the 14-day therapy, neither treatment duration provides acceptable eradication rate reaching 90% in per-protocol analysis. New combination regimen with higher efficacy should be developed as a first-line eradication therapy for H. pylori in Korea.     

Antibacterial effects of the urushiol component in the sap of the lacquer tree (Rhus verniciflua Stokes) on Helicobacter pylori

Background: Urushiol is a major component of the lacquer tree which has been used as a folk remedy for the relief of abdominal discomfort in Korea. The aim of this study was to evaluate the antibacterial effects of the urushiol on Helicobacter pylori. Materials and Methods: Monomer and 2–4 polymer urushiol were used. In the in vitro study, pH‐ and concentration‐dependent antibacterial activity of the urushiol against H. pylori were investigated. In addition, the serial morphological effects of urushiol on H. pylori were examined by electron microscopy. In vivo animal study was performed for the safety, eradication rate, and the effect on gastritis of urushiol. The expression of pro‐inflammatory cytokines was checked. Results: All strains survived within a pH 6.0–9.0. The minimal inhibitory concentrations of the extract against strains ranged 0.064–0.256 mg/mL. Urushiol caused separation of the membrane and lysis of H. pylori within 10 minutes. Urushiol (0.128 mg/mL × 7 days) did not cause complications on mice. The eradication rates were 33% in the urushiol monotherapy, 75% in the triple therapy (omeprazole + clarithromycin + metronidazole), and 100% in the urushiol + triple therapy, respectively. H. pylori‐induced gastritis was not changed by urushiol but reduced by eradication. Only the expression of interleukin‐1β in the gastric tissue was significantly increased by H. pylori infection and reduced by the urushiol and H. pylori eradication (p = .014). Conclusions: The urushiol has an antibacterial effect against H. pylori infection and can be used safely for H. pylori eradication in a mouse model.     

Variables Influencing Outcome of Helicobacter pylori Eradication Therapy in South China

Background: Therapy combining a proton pump inhibitor (PPI), clarithromycin and either amoxicillin or metronidazole is widely recommended for first‐line treatment for Helicobacter pylori infection. The purpose of this study was to examine the outcomes of PPI‐containing triple therapy and identify factors influencing the cure rate of H. pylori infection in South China. Materials and Methods: H. pylori positive patients with different occupations from 25 hospitals in five provinces of South China were enrolled. They received a PPI, metronidazole and amoxicillin triple therapy for a week. H. pylori eradication was evaluated by ¹³C‐urea breath test 4 weeks after therapy. Association between H. pylori eradication with occupation, gender, age, educational level, and protocol compliance was evaluated by Logistic regression. Results: Six hundred and seventy‐five were enrolled. The intention‐to‐treat and per‐protocol analyses showed overall cure rates of 60% (95% CI = 56.3–63.7%) and 64.5% (95% CI = 60.7–68.3%), respectively. Multivariate logistic regression showed that occupation, gender and protocol compliance were positively associated with the eradication rate (p < .01). The cure rate for those who took 80% or more of the prescribed drugs was 64.5% (95% CI = 60.7–68.3%) versus 14.6% (95% CI = 6–29%, p < .001) for those who took less. Lower eradication rates were also observed in farmers and women. Conclusions: The eradication rate with a PPI, metronidazole and amoxicillin triple therapy was unacceptably low in South China. These results suggest that studies of the eradication of H. pylori infection in China must take into account antibiotic resistance as well as patient occupation, gender, and protocol compliance. Gastric cancer and peptic ulcer disease are both important in China making methods to effectively and efficiently eradicate H. pylori a priority.