Regional differences in metronidazole resistance and increasing clarithromycin resistance among Helicobacter pylori isolates from Japan

Nationwide antibiotic resistance mapping of Helicobacter pylori in Korea: A prospective multicenter study

INTRODUCTION

The eradication rates for Helicobacter pylori have decreased in Korea although the prevalence of this bacterium has also decreased. Antibiotic resistance is likely to be a crucial factor in H. pylori eradication success, and we therefore mapped these resistance patterns nationwide in Korea.

MATERIALS AND METHODS

Five hundred and ninety adult subjects were prospectively enrolled from 2017 to 2018 from 15 centers across six geographic areas of Korea. A total of 580 biopsy tissues had been sampled from these patients during an upper endoscopy and were frozen at -80°C and delivered to a central laboratory. The agar dilution method was used to determine the minimum inhibitory concentration of amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, and levofloxacin for each H. pylori isolate.

RESULTS

The culture success rate was 60.2% (349/580). Resistance rates against clarithromycin, metronidazole, amoxicillin, tetracycline, levofloxacin, and ciprofloxacin were 17.8%, 29.5%, 9.5%, 0%, 37.0%, and 37.0%, respectively. The geographic distribution of metronidazole and quinolone resistance was highly variable. Some subjects had multiple H. pylori strains in the antrum and body of the stomach and showed a heterogeneous resistance profile between these anatomic areas. The H. pylori multidrug resistance (MDR) rate was 25.2% (88/349) among amoxicillin, clarithromycin, metronidazole, tetracycline, and quinolone and 11.2% (39/349) among four of these major antibiotics except for quinolone. The Seoul and Chungcheong areas showed a relatively lower MDR rate.

CONCLUSION

The antibiotic resistance of H. pylori differs by drug and geographic area in Korea. Detailed nationwide antibiotic resistance mapping is needed to develop an effective H. pylori eradication strategy.

Antibiotic dispensation rates among participants in community-driven health research projects in Arctic Canada

Background

Community-driven projects that aim to address public concerns about health risks from H. pylori infection in Indigenous Arctic communities (estimated H. pylori prevalence = 64%) show frequent failure of treatment to eliminate the bacterium. Among project participants, treatment effectiveness is reduced by antibiotic resistance of infecting H. pylori strains, which in turn, is associated with frequent exposure to antibiotics used to treat other infections. This analysis compares antibiotic dispensation rates in Canadian Arctic communities to rates in urban and rural populations in Alberta, a southern Canadian province.

Methods

Project staff collected antibiotic exposure histories for 297 participants enrolled during 2007–2012 in Aklavik, Tuktoyaktuk, and Fort McPherson in the Northwest Territories, and Old Crow, Yukon. Medical chart reviews collected data on systemic antibiotic dispensations for the 5-year period before enrolment for each participant. Antibiotic dispensation data for urban Edmonton, Alberta (average population ~ 860,000) and rural northern Alberta (average population ~ 450,000) during 2010–2013 were obtained from the Alberta Government Interactive Health Data Application.

Results

Antibiotic dispensation rates, estimated as dispensations/person-years (95% confidence interval) were: in Arctic communities, 0.89 (0.84, 0.94); in Edmonton, 0.55 (0.55, 0.56); in rural northern Alberta, 0.63 (0.62, 0.63). Antibiotic dispensation rates were higher in women and older age groups in all regions. In all regions, the highest dispensation rates occurred for β-lactam and macrolide antibiotic classes.

Conclusions

These results show more frequent antibiotic dispensation in Arctic communities relative to an urban and rural southern Canadian population.

Effect of Age on Effectiveness of Vonoprazan in Triple Therapy for Helicobacter pylori Eradication

Objective We evaluated the efficacy of vonoprazan-based eradication therapy for Helicobacter pylori (H. pylori), including the effects of age, gender, and grade of atrophy in comparison to proton pump inhibitor-based therapy. Method We retrospectively reviewed the records of 1,172 patients who received first-line triple therapy with amoxicillin, clarithromycin, and vonoprazan or a proton pump inhibitor (PPI) for H. pylori eradication, as well as 157 patients treated with second-line therapy consisting of amoxicillin, metronidazole, and vonoprazan or a PPI. Results The eradication rate of all cases treated with first-line triple therapy was 86.9% (1,019/1,172), while that in those treated with vonoprazan-based therapy was 92.5% (384/415). Our analysis showed that the use of vonoprazan resulted in a significantly improved success rate of first-line eradication therapy in comparison to proton pump inhibitor-based therapy [odds ratio (OR), 2.36; 95% confidence interval (CI) 1.55 to 3.56]. The superiority of vonoprazan was remarkable in non-elderly patients, while its effect was unclear in elderly patients. When used as second-line eradication therapy, the advantage of vonoprazan over PPI administration was not clear. Conclusion The inclusion of vonoprazan increased the success rate of first-line eradication therapy; however, the advantage was reduced with aging and remained unclear in elderly patients.

Second-line triple therapy in failures with vonoprazan-based triple therapy for eradication of Helicobacter pylori

Gastric acid inhibition during treatment is important for the eradication of Helicobacter pylori (H. pylori) infection. A novel potassium-competitive acid blocker, vonoprazan (VPZ), has been demonstrated to achieve high eradication rates; however, the efficacy of second-line treatment in failures of VPZ-based triple therapy has not been well studied. The aim of the current study was to determine the efficacy of VPZ in a first-line regimen for H. pylori eradication, and the efficacy of a second-line regimen using metronidazole (MTZ) in failures with the first-line regimen. Of 580 subjects enrolled in the study, 524 patients completed first-line treatment (275 patients who received VPZ and 249 patients who received LPZ). First-line regimens consisted of a combination of clarithromycin (CAM) 200 or 400 mg twice a day, amoxicillin (AMPC) 750 mg twice a day, and either LPZ 30 mg or VPZ 20 mg twice a day, administered orally for 7 days. CAM and VPZ/LPZ were replaced with metronidazole (MTZ) 250 mg and rabeprazole 10 mg in the second-line regimens. The eradication of H. pylori was assessed by the H. pylori stool antigen test. The overall first-line eradication rate with VPZ was significantly higher than that with LPZ [91.0% (250/275) vs. 84.7% (211/249), respectively, P=0.030]. The dose of CAM (400 vs. 800 mg) did not affect the eradication rate in either the VPZ or LPZ regimens. The overall eradication rates of the second-line regimens with MTZ did not differ significantly between the VPZ-failure and LPZ-failure groups [87.0% (20/23) vs. 87.9% (29/33), respectively, P=0.700]. Therefore, VPZ was significantly more effective than LPZ for first-line treatment. In patients with failure of first-line eradication therapy, successful results of second-line eradication therapy did not differ between the VPZ- and LPZ-failure groups. In conclusion, VPZ-based triple therapy should be recommended for eradication of H. pylori.

Antibiotic susceptibility, heteroresistance, and updated treatment strategies in Helicobacter pylori infection

In this review, we discuss the problem of antibiotic resistance, heteroresistance, the utility of cultures and antibiotic susceptibility tests in Helicobacter pylori (Hp) eradication, as well as the updated treatment strategies for this infection. The prevalence of antibiotic resistance is increasing all over the world, especially for metronidazole and clarithromycin, because of their heavy use in some geographical areas. Heteroresistance (simultaneous presence of both susceptible and resistant strains in different sites of a single stomach) is another important issue, as an isolate could be mistakenly considered susceptible if a single biopsy is used for antimicrobial tests. We also examined literature data regarding eradication success rates of culture-guided and empiric therapies. The empiric therapy and the one based on susceptibility testing, in Hp eradication, may depend on several factors such as concomitant diseases, the number of previous antibiotic treatments, differences in bacterial virulence in individuals with positive or negative cultures, together with local antibiotic resistance patterns in real-world settings. Updated treatment strategies in Hp infection presented in the guidelines of the Toronto Consensus Group (2016) are reported. These suggest to prolong eradication therapy up to 14 days, replacing the old triple therapy with a quadruple therapy based on proton pump inhibitor (PPI), bismuth, metronidazole, and tetracycline for most of the patients, or as an alternative quadruple therapy without bismuth, based on the use of PPI, amoxicillin, metronidazole, and clarithromycin. The new drug vonoprazan, a first-in-class potassium-competitive acid blocker recently approved in Japan, is also considered to be a promising solution for Hp eradication, even for clarithromycin-resistant strains. Furthermore, there is growing interest in finding new therapeutic strategies, such as the development of vaccines or the use of natural resources, including probiotics, plants, or nutraceuticals.

Novel and Effective Therapeutic Regimens for Helicobacter pylori in an Era of Increasing Antibiotic Resistance

Helicobacter pylori (H. pylori) is a common gastrointestinal bacterial strain closely associated with the incidence of chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. A current research and clinical challenge is the increased rate of antibiotic resistance in H. pylori, which has led to a decreased H. pylori eradication rate. In this article, we review recent H. pylori infection and reinfection rates and H. pylori resistance to antibiotics, and we discuss the pertinent treatments. A PubMed literature search was performed using the following keywords: Helicobacter pylori, infection, reinfection, antibiotic resistance, bismuth, proton pump inhibitors, vonoprazan, susceptibility, quintuple therapy, dual therapy, and probiotic. The prevalence of H. pylori has remained high in some areas despite the decreasing trend of H. pylori prevalence observed over time. Additionally, the H. pylori reinfection rate has varied in different countries due to socioeconomic and hygienic conditions. Helicobacter pylori monoresistance to clarithromycin, metronidazole or levofloxacin was common in most countries. However, the prevalence of amoxicillin and tetracycline resistance has remained low. Because H. pylori infection and reinfection present serious challenges and because H. pylori resistance to clarithromycin, metronidazole or levofloxacin remains high in most countries, the selection of an efficient regimen to eradicate H. pylori is critical. Currently, bismuth-containing quadruple therapies still achieve high eradication rates. Moreover, susceptibility-based therapies are alternatives because they may avoid the use of unnecessary antibiotics. Novel regimens, e.g., vonoprazan-containing triple therapies, quintuple therapies, high-dose dual therapies, and standard triple therapies with probiotics, require further studies concerning their efficiency and safety for treating H. pylori.

A Comparative Study of a New Class of Gastric Acid Suppressant Agent Named Vonoparazan versus Esomeprazole for the Eradication of Helicobacter pylori

BACKGROUND

Helicobacter pylori eradication rates have decreased worldwide. Gastric acid inhibition during treatment is important to eradicate these bacteria successfully. A new potassium-competitive acid blocker, vonoprazan (VPZ), has been shown to achieve high eradication rates in a previous randomized controlled trial.

OBJECTIVE

To determine the efficacy of VPZ for H. pylori eradication.

METHODS

A total of 874 patients were enrolled; 431 received esomeprazole (EPZ) and 443 received VPZ. First-line regimens contained clarithromycin (CAM) 200 mg b.i.d., amoxicillin 750 mg b.i.d., and either EPZ 20 mg b.i.d. or VPZ 20 mg b.i.d. for 7 days. Metronidazole 250 mg b.i.d. replaced CAM in the second-line regimens. The eradication of H. pylori was assessed by 13C-urea breath tests 4-8 weeks after each therapy.

RESULTS

The overall first-line eradication rate was 79.9% (341/427) with EPZ vs. 86.3% (377/439) with VPZ (p = 0.019). The second-line eradication rate was 83.3% (45/51) with EPZ vs. 91.1% (41/45) with VPZ (p = 0.900).

CONCLUSION

VPZ was significantly more effective than EPZ for first-line treatment. However, for second-line treatment, there was no significant difference between EPZ and VPZ.

Review article: the global emergence of Helicobacter pylori antibiotic resistance

BACKGROUND

Helicobacter pylori is one of the most prevalent global pathogens and can lead to gastrointestinal disease including peptic ulcers, gastric marginal zone lymphoma and gastric carcinoma.

AIM

To review recent trends in H. pylori antibiotic resistance rates, and to discuss diagnostics and treatment paradigms.

METHODS

A PubMed literature search using the following keywords: Helicobacter pylori, antibiotic resistance, clarithromycin, levofloxacin, metronidazole, prevalence, susceptibility testing.

RESULTS

The prevalence of bacterial antibiotic resistance is regionally variable and appears to be markedly increasing with time in many countries. Concordantly, the antimicrobial eradication rate of H. pylori has been declining globally. In particular, clarithromycin resistance has been rapidly increasing in many countries over the past decade, with rates as high as approximately 30% in Japan and Italy, 50% in China and 40% in Turkey; whereas resistance rates are much lower in Sweden and Taiwan, at approximately 15%; there are limited data in the USA. Other antibiotics show similar trends, although less pronounced.

CONCLUSIONS

Since the choice of empiric therapies should be predicated on accurate information regarding antibiotic resistance rates, there is a critical need for determination of current rates at a local scale, and perhaps in individual patients. Such information would not only guide selection of appropriate empiric antibiotic therapy but also inform the development of better methods to identify H. pylori antibiotic resistance at diagnosis. Patient-specific tailoring of effective antibiotic treatment strategies may lead to reduced treatment failures and less antibiotic resistance.

Clarithromycin-based standard triple therapy can still be effective for Helicobacter pylori eradication in some parts of the Korea

We evaluated the antibiotic resistance rates and eradication rates of clarithromycin based triple therapy from 2005 to 2010 retrospectively. In addition, we investigated the mechanism of clarithromycin resistance in Helicobacter pylori strains isolated from Korean patients. Two hundred and twelve strains of H. pylori were isolated from 204 patients. H. pylori ATCC 43504 was used as the standard strain. The eradication rates of H. pylori from 2005 to 2010 were 89.3%, 82.6%, 86.3%, 87.7%, 81.8%, and 84.2%, respectively. Total eradication rate was 84.9%. DNA sequences of the 23S RNA gene in clarithromycin-resistant strains were determined. The resistance rates of H. pylori to amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, moxifloxacin, and levofloxacin were 9.0%, 8.5%, 36.3%, 0%, 14.2%, 14.2%, and 14.2%, respectively. The multidrug resistance rate of H. pylori was 16.5%. Sequence analysis of clarithromycin-resistant strains showed an A2144G mutation in 8 of 14 strains (57.1%), a T2183C mutation in 5 of 14 strains (35.7%), and double mutations of both A2144G and T2183C in 1 of 14 strains (7.1%). In the present study, triple therapy may still be an effective eradication therapy for H. pylori infections in Korea. The A2144G and T2183C mutations are mainly present in clarithromycin-resistant isolates.

Antimicrobial resistance and characteristics of eradication therapy of Helicobacter pylori in Japan: a multi-generational comparison

BACKGROUND

Eradication of Helicobacter pylori (H. pylori) at a younger age is considered to be effective in preventing gastric cancer. This study assessed the characteristics of eradication therapy in young patients.

MATERIALS AND METHODS

We enrolled 1073 patients with H. pylori infection between 2000 and 2013. The subjects were divided into three groups according to age into the young (≤30 years), middle-aged (31-50 years), and elder (≥51 years) groups. We also examined 472 cases to investigate clinical eradication characteristics.

RESULTS

The rate of clarithromycin (CAM) resistance was 57.9%, 34.5%, and 35.2% in the young, middle-aged, and elder group, respectively, in 2012-2013 and was significantly higher in the young group than in the elder group (p = .01). Metronidazole (MNZ) resistance was similar among the three groups at each time point. While CAM resistance rose over the study period, MNZ resistance was noted to have decreased of late. The overall initial eradication success rate was 91.9% (95% CI, 89.1-94.1) in our cohort. Eradication efficiency was comparable in the young, middle-aged, and elder group at 94.3% (95% CI, 87.4-97.5), 90.2% (95% CI, 82.9-94.6), and 91.8% (95% CI, 88.1-94.5) respectively. Side effects such as skin rash were observed in 14.8%, 3.9%, and 3.5% of the respective groups. There were significant differences in the incidence of side effects between the young group and other groups (p < .05, respectively).

CONCLUSION

Since CAM resistance and the incidence of side effects are higher in young individuals, it is especially important to select eradication regimens based on testing for antimicrobial susceptibility.

Clinical management of Helicobacter pylori--the Japanese perspective

BACKGROUND

After the approval of health insurance coverage of eradication therapy for Helicobacter pylori-positive peptic ulcer disease (PUD) in 2000, comprehensive coverage for H. pylori infection itself was implemented in 2013.

METHODS

We did a literature search using PubMed database on the management of H. pylori infection including indications, regimens, outcomes of current eradication therapies, trends of antibiotic resistance rates and proposed third-line rescue therapy in Japan. We also collected data on changes of eradication rates in our hospital by searching electronic medical records.

RESULTS

After implementation of insurance coverage of eradication therapy for PUD, dramatic reduction of the number patients with PUD as well as spending on ulcer drug was documented. According to the current regulation, proton pump inhibitor (PPI)-based triple therapy with 2 antibiotics, amoxicillin (AMPC) plus clarithromycin, for 7 days is approved as the first-line therapy. After failure of the first-line therapy, PPI plus AMPC and metronidazole is authorized as the second line, which maintains an excellent eradication rate of over 90% in Japan. When these two therapies fail, a sitafloxacin-based therapy seems to be most promising among many rescue regimens.

CONCLUSION

Comprehensive public health insurance coverage of H. pylori infection will promote eradication in Japanese people infected with H. pylori, whose risk of developing gastric cancer has been shown to be high. It also provides us a unique opportunity to study whether the broader indications can accelerate the reduction of gastric cancer in Japan in the same way we witnessed the reduction of PUD.

Antisecretory Action of the Extract of the Aerial Parts of Eremomastax speciosa (Acanthaceae) Occurs through Antihistaminic and Anticholinergic Pathways

Objective. The objective of this study was to find out the possible antiulcer mechanism of action of Eremomastax speciosa. Method. Carbachol- and histamine-induced hypersecretion, associated with the pylorus ligation technique, were used in rats. Gastric mucosal ulceration, mucus production, pH, gastric volume, and acidity were measured. Results. Histamine and carbachol raised gastric acidity to 86.50 and 84.80 mEq/L, respectively, in the control rats, and the extracts (200 mg/kg) reduced gastric acidity to 34.60 and 39.00 mEq/L, respectively. Intraduodenal aqueous extract (400 mg/kg) in histamine- and carbachol-treated rats produced significant (P < 0.001) decreases in acid secretion to 28.50 and 28.80 mEq/L, respectively, and 100 percent inhibition of gastric ulceration. Augmented histamine-induced gastric acid secretion (90.20 mEq/L) was significantly reduced to 52.60 and 27.50 mEq/L by the 200 and 400 mg/kg doses of the aqueous extract, respectively. The extract significantly reduced (P < 0.001) the volume of gastric secretion and significantly increased mucus production. The ulcer inhibition potential of the extract significantly dropped to 25–44% (oral extract) and to 29–37% (duodenal extract) in carbachol/indomethacin-treated rats. Conclusion. The aqueous extract of E. speciosa has both cytoprotective and antisecretory effects. The antisecretory effect may involve a mechanism common to both cholinergic and histaminergic pathways.

Low Helicobacter pylori primary resistance to clarithromycin in gastric biopsy specimens from dyspeptic patients of a city in the interior of São Paulo, Brazil

BACKGROUND

Clarithromycin, amoxicillin, and a pump proton inhibitor are the most common drugs recommended as first-line triple therapy for H.pylori treatment, which results in eradication rates close to 80%, varying regionally, principally due to emergency cases and increases of clarithromycin resistant strains. Nucleotide substitutions at the H. pylori domain V of the 23S rRNA fraction are involved in the macrolide resistance and the A2142G and A2143G mutations are predominant in clinical isolates worldwide including in Brazil. As H. pylori culture is fastidious, we investigated the primary occurrence of H. pylori A2142G and A2143G rDNA 23S mutations using a molecular approach directly on gastric biopsies of dyspeptic patients consecutively attended at Hospital das Clinicas of Marilia, São Paulo, Brazil.

METHODS

Biopsy specimens obtained from 1137 dyspeptic patients, were subjected to histopathology and H. pylori diagnosis by histology and PCR. PCR/RFLP assay was used to detect A2142G and A2143G point mutations at domain V of the H. pylori 23S rDNA associated with clarithromycin resistance. Through the developed assay, a 768 bp PCR amplicon corresponding to1728 to 2495 bp of the 23S H. pylori rDNA is restricted with MboII for A2142G mutation detection and with BsaI for A2143G mutation detection. Occurrence of 23S rDNA A2142G results in two DNA fragments (418 and 350 bp) and of 23S rDNA A2143G results in three DNA fragments (108, 310 and 350pb), due to a conserved BsaI restriction site.

RESULTS

The PCR method used to diagnose H. pylori presented sensitivity, specificity and accuracy of 77,6%, 79,3% and 78,6%, respectively, compared to histology, the gold standard method for H. pylori diagnosis used in our routine. Prevalence of H.pylori with clarithromycin resistant genotypes was 2,46%, with predominance of A2143G 23S rDNA point mutation.

CONCLUSIONS

The PCR/RFLP assay was a rapid and accurate H.pylori diagnostic and clarithromycin resistance determination method useful for routine practice. As prevalence of primary resistance of H.pylori to clarithromycin due to A2142G and A2143G mutations remains low in Marilia, the standard clarithromycin containing triple therapy is still valid.

Trends of second-line eradication therapy for Helicobacter pylori in Japan: a multicenter study in the Tokyo metropolitan area

BACKGROUND

In Japan, the eradication rate of first-line therapy for Helicobacter pylori (H. pylori) with a proton pump inhibitor (PPI), amoxicillin (AMPC) and clarithromycin (CAM) has been decreasing because of a high prevalence of CAM resistance. A possible decrease of the eradication rate for second-line therapy with a PPI, AMPC and metronidazole (MNZ) is of concern. The aim of this study is to assess the trends in second-line eradication therapy for H. pylori in Japan.

MATERIALS AND METHODS

We accumulated data retrospectively on patients administered second-line eradication therapy for Helicobacter pylori with a PPI, AMPC, and MNZ for 1 week after failure of first-line eradication therapy with a PPI, AMPC and CAM at 15 facilities in the Tokyo metropolitan area in Japan from 2007 to 2011. Trends for second-line eradication rates in modified intention-to-treat (ITT) analyses were investigated. Second-line eradication rates were categorized by three PPIs (rabeprazole (RPZ), lansoprazole (LPZ) or omeprazole (OMZ)) and evaluated.

RESULTS

We accumulated data on 1373 patients. The overall second-line eradication rate was 92.4%. Second-line eradication rates in 2007, 2008, 2009, 2010 and 2011 were 97.7, 90.6, 94.5, 91.8 and 91.8%, respectively, with no significant trends revealed. Second-line eradication rates categorized by three PPIs for the entire 5-year period were 91.6, 93.4 and 92.4% (RPZ, LPZ and OPZ, respectively) with no significant differences among the three PPIs.

CONCLUSIONS

From 2007 to 2011, there were no significant trends in the second-line eradication rates and the rates remained consistently high. From the viewpoint of high prevalence of CAM resistance in Japan, triple therapy with PPI, AMPC and MNZ may be a better strategy for first-line therapy compared to triple therapy with PPI, AMPC and CAM.

Antibiotic resistance of Helicobacter pylori isolated in the Southeast Coastal Region of China

BACKGROUND

The resistance of Helicobacter pylori (H. pylori) to antibiotics is increasing worldwide, lowering its efficacy in current eradication therapies. This study evaluated H. pylori resistance to antibiotics in the southeast coastal region of China and suggests appropriate alternatives.

MATERIALS AND METHODS

Seventeen thousand seven hundred and thirty one H. pylori strains were collected from eight areas of two provinces in coastal southeast China from 2010 to 2012. The resistance of these strains to six antibiotics was tested using the agar dilution method.

RESULTS

The resistance rates to clarithromycin, metronidazole, levofloxacin, amoxicillin, gentamicin and furazolidone were 21.5, 95.4, 20.6, 0.1, 0.1 and 0.1%, respectively. Double, triple and quadruple antibacterial resistant percentages were 25.5, 7.5 and 0.1%, respectively. A positive association between the resistance to levofloxacin and to clarithromycin was found, but there was a negative correlation in the resistances to levofloxacin and to metronidazole.

CONCLUSIONS

The prevalence of H. pylori resistance to clarithromycin, metronidazole, levofloxacin and multiple antibiotics in coastal southeast China is high. Choice of therapy should be individualized based on a susceptibility test in this region of the country.

Treatment for Eradication of Helicobacter pylori Infection among Chronic Hepatitis C Patients

BACKGROUND/AIMS

Helicobacter pylori infection causes gastritis, peptic ulcers and gastric malignancies, and its eradication has been advocated by many groups. We determined the H. pylori carrier status and eradication rates of patients with chronic hepatitis C virus (HCV) infection.

METHODS

In total, 76 chronically HCV-infected patients were enrolled for comparison with 228 HCV-noninfected, age- and sex-matched controls. H. pylori infection was confirmed by H. pylori antibody and urea breath testing.

RESULTS

The H. pylori infection rate was significantly higher for HCV-infected patients (67 of 76, 88.2%) than for HCV-noninfected controls (158 of 228, 69.3%). Endoscopic findings showed that the rates of gastric ulcers and gastritis were significantly higher for the 67 HCV-infected patients with H. pylori infection (34.3% and 77.6%) than for the 158 HCV-noninfected controls with H. pylori infection (15.2% and 57.6%). Treatment to eradicate H. pylori had a significantly higher success rate for HCV-infected patients (61 of 67, 91.0%) than for HCV-noninfected controls (115 of 158, 72.8%).

CONCLUSIONS

The markedly high H. pylori eradication rate observed in this study shows that eradication of H. pylori holds promise for the improvement of the long-term health condition of patients with chronic HCV infection.

Randomised clinical trial: the efficacy of a 10-day sequential therapy vs. a 14-day standard proton pump inhibitor-based triple therapy for Helicobacter pylori in Korea

BACKGROUND

The eradication rates of Helicobacter pylori (H. pylori) using a proton pump inhibitor (PPI)-based triple therapy have declined due to antibiotic resistance worldwide.

AIM

To compare the eradication rate of the 10-day sequential therapy for H. pylori infection with that of the 14-day standard PPI-based triple therapy.

METHODS

This was a prospective, randomised, controlled study. A total of 409 patients with H. pylori infection were randomly assigned to receive either the 10-day sequential therapy regimen, which consisted of pantoprazole (40 mg) plus amoxicillin (1000 mg) twice a day for 5 days, then pantoprazole (40 mg) with clarithromycin (500 mg) and metronidazole (500 mg) twice a day for another five consecutive days or the 14-day PPI-based triple therapy regimen, which consisted of pantoprazole (40 mg) with amoxicillin (1000 mg) and clarithromycin (500 mg) twice a day for 14 days. The pre- and post-treatment H. pylori status were assessed by rapid urease test, urea breath test, or histology. Successful eradication was confirmed at least 4 weeks after finishing the treatment.

RESULTS

In the intention-to-treat analysis, the eradication rates of the 10-day sequential therapy and of the 14-day PPI-based triple therapy were 85.9% (176/205) and 75.0% (153/205), respectively (P = 0.006). In the per-protocol analysis, the eradication rates were 92.6% (175/205) and 85% (153/204), respectively (P = 0.019). There was no statistically significant difference between the two investigated groups regarding the occurrence of adverse event rates (18.9% vs. 13.3%, P = 0.143).

CONCLUSION

The 10-day sequential therapy achieved significantly higher eradication rates than the 14-day standard PPI-based triple therapy in Korea.

[Regional difference of antibiotic resistance of helicobacter pylori strains in Korea]

BACKGROUND/AIMS

This study was performed to compare the prevalence rates of primary antibiotic resistance in Helicobacter pylori (H. pylori) isolates among different regions of Korea.

METHODS

H. pylori were isolated from gastric mucosal biopsy specimens of 99 Koreans who lived in Gyeonggi (n=40), Kangwon province (n=40) and Busan (n=19) from April to August in 2008. All the patients had no history of H. pylori eradication therapy. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin, and moxifloxacin were tested according to the agar dilution method.

RESULTS

There was a difference in resistance to clarithromycin in three institutes located among Gyeonggi (32.5%), Kangwon province (12.5%) and Busan (42.1%) by One way ANOVA test (p=0.027) and nonparametric Kruskal Wallis test (p=0.027). However, by post-hoc analysis, there was no statistically significant difference among three regions. Similarly, the other 7 antibiotics (amoxicillin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin) did not show any significant difference.

CONCLUSIONS

There was no significant regional difference of the primary antibiotic resistance of H. pylori. However, the included patient number might not be enough for this conclusion demanding further evaluations.

Quadruple therapy with ecabet sodium, omeprazole, amoxicillin and metronidazole is effective for eradication of Helicobacter pylori after failure of first-line therapy (KDOG0201 Study)

BACKGROUND AND OBJECT

An antiulcer agent, ecabet sodium, is active against Helicobacter pylori. The aim of the present study was to clinically examine whether eradication therapy, which includes ecabet sodium, is effective in eradication of H. pylori after failure of first-line therapy.

METHODS

Patients with peptic ulcer who failed with first-line triple eradication therapy containing clarithromycin received quadruple therapy with omeprazole (20 mg, twice daily), amoxicillin (750 mg, twice daily), metronidazole (500 mg, twice daily) and ecabet sodium (1000 mg, twice daily) for 14 days. Eradication of H. pylori was judged by 13C-urea breath test 8 weeks later.

RESULTS

Fifty-two patients (36 men and 16 women) were included. Their mean age was 51.4 years (range 28-73). One patient dropped out because of diarrhoea. The eradication rate was 98.0% (50/51) according to the per-protocol analysis and 96.2% (50/52) according to the intention-to-treat analysis. Side effects occurred in seven patients, but none were serious.

CONCLUSIONS

Quadruple therapy including ecabet sodium is useful as second-line eradication treatment for H. pylori.

Change in antibiotic resistance of Helicobacter pylori strains and the effect of A2143G point mutation of 23S rRNA on the eradication of H. pylori in a single center of Korea

BACKGROUND

The current prevalence of primary antibiotic resistance of H. pylori is not known in Korea. This study was done to evaluate the prevalence of primary antibiotic resistance of H. pylori, and to evaluate the effect of point mutations of 23S rRNA on the rate of eradication of H. pylori.

METHODS

H. pylori were isolated from gastric mucosal biopsy specimens obtained from 222 Koreans. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, and levofloxacin were examined using the agar dilution method. DNA sequencing was carried out to detect H. pylori 23S rRNA mutations.

RESULTS

The resistance to clarithromycin, tetracycline, ciprofloxacin, and levofloxacin increased during the period of 2007 to 2009 compared with 2003 to 2005 (P<0.05). However, amoxicillin and metronidazole resistance slightly decreased. The rates of eradication were 95.5% for the clarithromycin-sensitive strains, which was higher than the 67.9% for the clarithromycin-resistant strains (P=0.001). By contrast, the eradication rate was 100% in patients with amoxicillin-resistant H. pylori. Among 26 clarithromyin-resistant strains, 6 (23%) had A2143G mutations, and all of the cases in which these mutations were present were not eradicated by proton pump inhibitor-based triple therapy (P=0.0004). By contrast, none of the 26 clarithromyin-sensitive strains had A2143G mutations. The T2183C and A2223G mutations were frequently found in the sensitive strains and in the resistant strains.

CONCLUSIONS

Clarithromycin resistance of H. pylori, which determined the efficacy of H. pylori eradication of proton pump inhibitor triple regimen, was found to be increased in a single center study. A2143G was an important 23S rRNA mutation associated with clarithromycin resistance and affected the H. pylori eradication efficacy.

Helicobacter pylori resistance to metronidazole and clarithromycin in Ireland

INTRODUCTION

Helicobacter pylori eradication rates have fallen considerably in recent years. Antibiotic resistance is thought to be rising.

OBJECTIVES

To examine the levels of resistance to metronidazole (MTZ) and clarithromycin (CLA) in H. pylori, isolates were taken in a reference centre in Ireland from 2007 to 2008 and were compared to a similar cohort from a study in 1997.

METHOD

Antimicrobial susceptibilities were tested by E-test. Frequencies of spontaneous metronidazole and clarithromycin resistance were measured on an agar plate containing the antibiotics at concentrations of 2x and 4x minimum inhibition concentration values. Clinical data were obtained from charts, laboratory and endoscopy reports.

RESULTS

Two hundred and twenty-two patients were analyzed, 98 were females. Colonies amenable to culture were grown in 219 patients. Thirty-seven had prior attempts at eradication therapy (all with amoxicillin-CLA-proton pump inhibitor. A total of 31.5% of the patients had strains resistant to MTZ and 13.2% of the patients were noted to have strains resistant to CLA. About 8.6% of the patients had strains resistant to both the agents. CLA resistance was 9.3% in those who had no prior eradication therapy compared with 32.4% of those who had. CLA resistance increased from 3.9%, among treatment-naive patients in 1997, to 9.3% in our study. MTZ resistance was 29.1% in the treatment-naive population. In 1997, MTZ resistance in the treatment-naive cohort was 27.1%. MTZ resistance was more likely to occur in females (35.4 vs. 28.5%) than in males.

CONCLUSION

This study shows that resistance to CLA among Irish patients infected with H. pylori has increased since 1997. The future of treatment may well lie in the widespread use of sensitivity testing before the treatment. This would promote an accurate treatment.

Homology model of the DNA gyrase enzyme of Helicobacter pylori, a target of quinolone-based eradication therapy

BACKGROUND AND AIMS

Resistance of Helicobacter pylori to the standard therapeutic antimicrobial agents has been demonstrated. Although quinolones are an alternative candidate for third-line eradication therapy, quinolone resistance of H. pylori is also increasing. Quinolone resistance of H. pylori is caused by a point mutation of the DNA gyrase subunit A (GyrA) protein, especially on amino acids 87 and 91. The aim of this study is to surmise the structure of H. pylori GryA.

METHODS

The modeling of the 3-D structure of H. pylori GyrA was performed by an automated homology modeling program: SWISS-MODEL. The position of amino acids 87 and 91 in H. pylori GyrA was plotted on the homology model. To estimate the function of quinolone resistance-determining region (QRDR), the structure of H. pylori GyrA was compared with Escherichia coli GyrA.

RESULTS

A molecular model of H. pylori GyrA could be predicted using SWISS-MODEL. The GyrA N- and C-terminal domains closely resembled those of E. coli. The position of amino acids 87 and 91 in H. pylori GyrA was part of the DNA binding region (head dimer interface) on the GyrA N-terminal domain.

CONCLUSION

Our homology model of H. pylori GryA suggests that the quinolone resistance-determining region is on the head dimer interface of the GyrA N-terminal domain.

A randomized controlled trial: efficacy and safety of azithromycin, ofloxacin, bismuth, and omeprazole compared with amoxicillin, clarithromycin, bismuth, and omeprazole as second-line therapy in patients with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection of the stomach is widespread among human populations and is considered to play a major role in the pathogenesis of various diseases such as peptic ulcer, adenocarcinoma, and mucosa associated lymphoid tissue (MALT) lymphoma of the stomach. To increase H. pylori eradication rate without increasing bacterial resistance, various regimens have been recommended. Commonly the association of at least two antibiotics with a proton-pump inhibitor is used. The treatment regimens for second-line therapy, suggested in studies from the western world may not be ideal in Iran.

AIM

In this study, we evaluated the safety and efficacy of a new quadruple therapy regimen and compared it with the standard second-line treatment for H. pylori eradication.

METHODS

We selected 220 H. pylori positive patients, with a clear indication of eradication therapy, who did not respond to a 2 weeks treatment with metronidazole, amoxicillin, omeprazole, and bismuth. They were randomized into two groups. Group A (n = 110) were treated with azithromycin, ofloxacin, bismuth, and omeprazole and group B (n = 110) with amoxicillin, clarithromycin, bismuth, and omeprazole for 2 weeks. Four weeks after the end of treatment, urea breath test was performed for all subjects to confirm eradication.

RESULTS

In intention-to-treat analysis, the rate of H. pylori eradication in groups A and B was 77.3% (85/110) and 64.5% (71/110) respectively (p = .027). In per-protocol analysis, the rate of H. pylori eradication in groups A and B was 86.7 and 74.7%, respectively (p = .026). The incidence of poor compliance was lower, although not significantly so, in group A than group B (3.5 vs 4.3%). No major adverse events occurred in both groups.

CONCLUSION

Two weeks of treatment with ofloxacin, azithromycin, omeprazole, and bismuth is an effective and safe regimen for H. pylori eradication as second-line therapy.

Clarithromycin resistance and point mutations in the 23S rRNA gene in Helicobacter pylori isolates from Malaysia

OBJECTIVE

To determine the prevalence of primary clarithromycin resistance amongst Helicobacter pylori (H. pylori) strains in Malaysian patients with gastroduodenal diseases, by using restriction fragment length polymorphism (RFLP) in domain V of 23S rRNA.

METHODS

Gastric biopsies were obtained from H. pylori positive patients undergoing gastroscopy. DNA extraction was followed by PCR amplification using the primers Hp23-1 and Hp23-2 flanking a region of 425bp within the bacterial 23S rRNA peptidyltranferase (Hp23S fragment). Analysis of the 23S rRNA gene mutations is based on the generation of restriction sites for two restriction enzymes: BbsI and BsaI, which correspond to the base substitutions characteristic of clarithromycin resistance from A to G at positions 2142 and 2143, respectively.

RESULTS

Gastric biopsy samples were obtained from 107 patients. A fragment of size 425bp corresponding to that expected from amplification of domain V of 23S rRNA was PCR-amplified from only 105 samples. The amplicon was subsequently subjected to restriction by BbsI and BsaI. Only 1 sample (0.95%) had the BbsI mutation (base substitution at A2142G) and 2 samples (1.90%) the BsaI mutation (base substitution at A2143G). Thus 3 of 105 (2.9%) samples harbored clarithromycin resistant strains.

CONCLUSION

In our experience, PCR-RFLP is a rapid and precise method to detect the resistance of H. pylori to clarithromycin. Using this method, a low prevalence of clarithromycin resistance was detected in our local Malaysian strains. This augurs well for the continued use of clarithromycin as a first line drug in the treatment and eradication of H. pylori infection.

In vitro and in vivo anti-Helicobacter/Campylobacter activity of the aqueous extract of Enantia chlorantha

The aqueous extract of Enantia chlorantha Oliver (Annonaceae) stem bark, a plant widely used in Cameroon for the traditional treatment of gastritis and stomach problems, was assessed for in vitro and in vivo anti-Helicobacter/Campylobacter properties using the well diffusion assay, agar dilution assay, and killing rate determination. The in vitro activity was dose-dependent, and the same antimicrobial parameters (MAQ = 0.63 mg; MIC = 0.39 mg/mL; MBC = 1.56 mg/mL; ET(100) = 8 h) were obtained for both H. pylori and C. jejuni/coli. When the plasma active principle concentration equivalence was determined in vitro using plasma from rats exposed to a single dose (3000 mg/kg) of the extract, the peak absorption of E. chlorantha active principle against H. pylori occurred at 2 h. Plasma activity was nil 8 h after extract administration. The in vivo H. pylori eradication potency of the extract was assessed using mice infected with H. pylori. Antral mucus sample cultures from mice treated with E. chlorantha extract (500 and 1000 mg/kg for 3 days) did not yield any growth. The results suggest that in addition to its in vitro activity, E. chlorantha water extract also possesses in vivo antibiotic effects against H. pylori.

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. From 1996 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.

Impact of quadruple regimen of clarithromycin added to metronidazole-containing triple therapy against Helicobacter pylori infection following clarithromycin-containing triple-therapy failure

BACKGROUND

The establishment of an optimal second-line regimen for Helicobacter pylori infection is required. Although quadruple therapy should overcome resistance to either clarithromycin or metronidazole, the effects of a quadruple regimen in second-line therapy are unknown. This study aims to evaluate the efficacy of triple therapy composed of proton pump inhibitor/amoxicillin plus metronidazole with the combined additive effects of clarithromycin as a second-line quadruple therapy against H. pylori infection.

MATERIALS AND METHODS

Participants were 104 patients in whom first-line therapy containing proton pump inhibitor-amoxicillin-clarithromycin failed. Before starting second-line therapy, patients underwent endoscopy to obtain H. pylori strain for antibiotic susceptibility tests. Patients were randomized to receive rabeprazole (10 mg), amoxicillin (750 mg), and metronidazole (250 mg), either with clarithromycin (200 mg; RAMC group) or without (RAM group); all treatments were administered twice daily for 7 days. H. pylori eradication was confirmed by (13)C-urea breath tests performed 2 to 3 months post-therapy.

RESULTS

As shown by intention-to-treat/per-protocol analyses, the cure rates for H. pylori infection were 88.5%/93.9% and 82.7%/84.3% for the RAMC and RAM groups. Although the study probably had an insufficient power to show a significant difference between the cure rates of the two regimens, the eradication rates showed a clear trend in favor of the RAMC group. There were no severe side-effects in any group.

CONCLUSIONS

In Japan, the RAMC regimen is thought to be a promising alternative strategy for second-line eradication of H. pylori infection.

Evaluation of clinical and socio-demographic risk factors for antibacterial resistance of Helicobacter pylori in Bulgaria

The aim of this study was to assess the clinical and socio-demographic risk factors for primary Helicobacter pylori antibacterial resistance. In total, 266 consecutive H. pylori strains, from untreated symptomatic adult patients who answered a questionnaire, were evaluated. Strain susceptibility to amoxicillin, metronidazole, clarithromycin and tetracycline was tested by a breakpoint susceptibility test. Metronidazole resistance was found in fewer (17.0 %) peptic ulcer patients than in non-ulcer subjects (28.3 %, P=0.037), as well as in fewer patients born in villages (12.7 %) than in those born in towns (27.6 %, P=0.016). Clarithromycin resistance varied from 8.8 to 23.4 % (P=0.009) within the hospital centres. The highest clarithromycin resistance rate was found in hospital centre A (23.4 %) compared to other centres (12.9 %, P=0.041). The factors sex, age, symptom duration, non-steroidal anti-inflammatory drug use, diabetes, type of profession and educational level were not associated with H. pylori resistance. Logistic regression revealed that the risk factors for metronidazole resistance were non-ulcer disease [odds ratio (OR) 1.95, 95 % confidence interval (95 % CI) 1.04-3.65] and a birthplace of a town (OR 2.64, 95 % CI 1.18-5.93). The hospital centre may be a risk factor (OR 2.07, 95 % CI 1.02-4.21) for clarithromycin resistance but further studies are required to verify this suggestion. In conclusion, the knowledge of the risk factors for H. pylori resistance to antibacterials could facilitate the treatment choice for H. pylori eradication.

Evaluation of three different proton pump inhibitors with amoxicillin and metronidazole in retreatment for Helicobacter pylori infection

GOALS

We compared the eradication results of retreatment of eradication with proton pump inhibitor (PPI) plus amoxicillin and metronidazole for patients with Helicobacter pylori infection not eradicated by initial treatment with PPI plus amoxicillin and clarithromycin.

BACKGROUND

In Japan, the guideline proposes that the use of metronidazole in a triple therapy containing PPI, PPI plus amoxicillin and metronidazole is desirable in retreatment. However, there are no reports comparing various retreatment using different PPIs.

METHODS

After initial treatment failure with a PPI plus amoxicillin and clarithromycin, 169 patients were randomized to a PPI (rabeprazole, lansoprazole, or omeprazole) plus amoxicillin and metronidazole given b.i.d. for 7 days.

RESULTS

Pretreatment susceptibility testing showed a high level of clarithromycin resistance (78%). The over all eradication rates were similar with the 3 PPIs, 91.1% range 90.1 to 91.4 with intention-to-treat analysis. The presence of metronidazole resistance reduced the eradication rate by approximately 40% (from 96.6% to 57.1%, P<0.05).

CONCLUSIONS

In Japan, the combination of a PPI plus amoxicillin and metronidazole provide excellent eradication rates after initial treatment failure with a PPI plus amoxicillin and clarithromycin. The results with metronidazole resistant strains are less satisfactory and pretreatment susceptibility testing may become needed if the prevalence of metronidazole resistant H. pylori increase.

Efficacy and safety of faropenem in eradication therapy of Helicobacter pylori

AIMS

While triple therapy with a proton pump inhibitor, amoxicillin, and clarithromycin is the standard therapy for Helicobacter pylori eradication, it is ineffective against clarithromycin-resistant strains. To seek a better regimen for eradication therapy, we assessed the sensitivity of clinical strains seen in Japan to faropenem and then evaluated the efficacy and safety of eradication therapy containing this antibiotic.

METHODS

Minimum inhibitory concentrations (MICs) of faropenem were determined in 78 Japanese clinical H. pylori isolates using the agar dilution method. H. pylori-positive patients were consecutively assigned to a 7-day eradication therapy protocol with LAF (lansoprazole 60 mg/day, amoxicillin 2000 mg/day, and faropenem 600 mg/day), and then to a 14-day protocol. The outcomes of the therapies were assessed by (13)C-urea breath tests.

RESULTS

All 78 strains showed MICs of faropenem that were equal to or less than 0.2 microg/mL. The eradication rates according to intention-to-treat analyses were 46.5% with the 7-day therapy (n = 43) and 62.5% with the 14-day therapy (n = 32). No special measures were required to treat the adverse events observed in approximately one-third of the patients.

CONCLUSIONS

Faropenem was found to have good antimicrobial action against H. pylori in vitro. The 14-day LAF therapy successfully eradicated H. pylori in about two-thirds of the patients although the incidence of adverse events was high.

Detection of mixed clarithromycin-resistant and -susceptible Helicobacter pylori using nested PCR and direct sequencing of DNA extracted from faeces

The major cause of chemotherapy failure in patients with chronic gastritis and peptic ulcers caused by Helicobacter pylori is clarithromycin (CAM) resistance due to a mutation in the 23S rRNA gene. This study describes a non-invasive and accurate method for the detection of mixed CAM-resistant and -susceptible H. pylori by sequencing of the H. pylori 23S rRNA gene. Faeces were crushed with beads and the 23S rRNA gene was amplified using a nested PCR on the extracted DNA. Mutation analysis of this gene using this method showed that 20.4 % of patients carried mixed CAM-susceptible (wild type) and -resistant (A2142G or A2143G mutant) H. pylori. Furthermore, it was found that 66.6 % of patients who had been treated unsuccessfully carried one of these mutations in the 23S rRNA gene (including the mixed type), whilst standard culture detected CAM-resistant isolates in only 22.2 % of patients with unsuccessful treatment. These data suggest that, for successful therapy, the diagnosis method described here would more accurately detect CAM-resistant H. pylori, including mixed infections.

Changing antimicrobial susceptibility epidemiology of Helicobacter pylori strains in Japan between 2002 and 2005

Surveillance of Helicobacter pylori antimicrobial susceptibility reflecting the general population in Japan is limited. The antimicrobial susceptibilities of 3,707 H. pylori strains isolated from gastric mucosa samples of previously untreated patients diagnosed with gastroduodenal diseases at 36 medical facilities located throughout Japan between October 2002 and September 2005 were evaluated. Using an agar dilution method for antimicrobial susceptibility testing of H. pylori, the MIC distributions and trends during the study period for clarithromycin, amoxicillin, and metronidazole were studied. While the MIC(50) and MIC(90) for clarithromycin did not change during the 3-year period, the MIC(80) showed a 128-fold increase. Furthermore, the rate of resistance increased yearly from 18.9% (2002 to 2003) to 21.1% (2003 to 2004) and 27.7% (2004 to 2005). With a resistance rate of 19.2% among males compared to 27.0% among females, a significant gender difference was observed (P < 0.0001). Our study shows that in Japan, there is an evolving trend towards increased resistance to clarithromycin with geographical and gender differences as well as between clinical disease conditions. No significant changes in resistance were observed for amoxicillin and metronidazole during the period. While the benefit of H. pylori antimicrobial susceptibility testing has been debated in Japan, current empirical regimens are not based on susceptibility data representative of the general population. The development of an effective H. pylori eradication regimen in Japan will require continued resistance surveillance as well as a better understanding of the epidemiology of resistance.

Comparison of 1- and 2-week pantoprazole-based triple therapies in clarithromycin-sensitive and resistant cases

BACKGROUND

The objectives of this prospective study were: (i) to compare the efficacy of 1-week with 2-week pantoprazole-based triple therapy and (ii) to evaluate the impact of clarithromycin resistance on Helicobacter pylori (H. pylori) eradication rates.

METHODS

Eighty dyspeptic patients were randomly allocated to two groups. The first group (PAC-1, n=40) received pantoprazole 40 mg, amoxicillin 1000 mg, and clarithromycin 500 mg twice a day for one week, and the second group (PAC-2, n=40) received the same regimen for two weeks. Endoscopy was repeated one month after the end of the treatment.

RESULTS

DNA extraction for clarithromycin resistance could not be performed in seven cases. Five cases were lost to follow-up. Clarithromycin resistance was found to be 44.1% (15/34) in the PAC-1 group and 58.8% (20/34) in the PAC-2 group (p>0.05). Eradication was achieved in 16 (PP: 47.1%, ITT: 44.4%) and 25 (PP:73.5%, ITT: 67.6%) patients in the PAC-1 and PAC-2 groups, respectively (p>0.05). H. pylori was eradicated in 4 of 15 (PP: 26.7%, ITT: 26.7%) clarithromycin-resistant patients in the PAC-1 group and in 12 of 20 (PP: 60%, ITT: 60%) clarithromycin-resistant patients in the PAC-2 group (p>0.05). Among the clarithromycin-sensitive ones, eradication was achieved in 12 of 19 (PP: 63.2%, ITT: 57.1%) patients in the PAC-1 group and in 13 of 14 (PP: 92.8%, ITT: 76.5%) patients in the PAC-2 group (p>0.05).

CONCLUSION

Although the 2-week regimen of pantoprazole-based triple therapy was effective for H. pylori eradication in clarithromycin-sensitive cases, highly effective H. pylori eradication protocols are needed for clarithromycin-resistant ones.

High Helicobacter pylori resistance rate to clarithromycin in Turkey

GOALS

To assess the resistance of Helicobacter pylori to clarithromycin in Turkey.

BACKGROUND

Recent studies have emphasized the remarkable reduction in H. pylori eradication rates. Resistance to clarithromycin is the most important factor affecting the success of H. pylori eradication therapies.

STUDY

The study involved 110 consecutive adult dyspeptic patients infected with H. pylori. Resistance to clarithromycin was studied by real-time polymerase chain reaction method on gastric biopsy specimens.

RESULTS

Of the 110 patients, 56 (50.9%) were male and mean age (+/-SD) was 45.1+/-13.1 years. Overall, 53 (48.2%) patients were found to be resistant to clarithromycin. Resistance to clarithromycin was not statistically associated with age, sex, previous macrolide use, residence (urban/rural), education status, and presence of peptic ulcer.

CONCLUSIONS

The rate of resistance to clarithromycin was found to be markedly high. This result may explain the recently reported low success rates of H. pylori eradication therapies with clarithromycin.

Resistance rate to antibiotics of Helicobacter pylori isolates in eastern Taiwan

BACKGROUND AND AIM

Prevalence of Helicobacter pylori (H. pylori) strains resistant to metronidazole, clarithromycin and amoxicillin is increasing worldwide. The aim of this study was to determine the antibiotic susceptibility patterns in H. pylori strains isolated from eastern Taiwan.

METHODS

One strain each of H. pylori was isolated from 133 symptomatic patients and subjected to determination of the minimal inhibitory concentration (MIC) by the Epsilometer test (E-test) for four antibiotics commonly used in the treatment of H. pylori infections.

RESULTS

None of the strains were resistant to tetracycline. Resistance to metronidazole (8 microg/mL), clarithromycin (1 microg/mL) and amoxicillin (8 microg/mL) was found in 51.9%, 13.5% and 36.1% of the isolates, respectively. Metronidazole-resistant strains were isolated more frequently from women (49/78; 62.8%) than from men (20/55; 36.4%). Resistance to at least two antimicrobial agents was detected in 33.8% of the isolates. There was a high rate of resistance to both metronidazole and amoxicillin (18.1%).

CONCLUSIONS

Clarithromycin and tetracycline may provide useful components of treatment regimens in eastern Taiwan. In addition, pretreatment microbial susceptibility testing rather than empiric therapy is highly recommended for eradication of H. pylori infection.

Effective regimens for the treatment of Helicobacter pylori infection

Successful Helicobacter pylori eradication therapy remains a challenge in medical practice. Currently, a proton pump inhibitor-based triple therapy containing clarithromycin, amoxicillin or nitroimidazole for 7 days is the recommended first-line treatment approach with an expected eradication success rate of approximately 80%. As a second-line treatment option in the case of failure, a ranitidine bismuth citrate-based quadruple therapy is currently recommended curing another 80% of patients, leaving a subset of patients with persistent H. pylori infection. For these patients, promising rescue options have been evaluated including regimens that contain rifabutin, quinolones, furazolidone or high-dose amoxicillin. The role of susceptibility testing is still under discussion. It is not generally recommended prior to first-line treatment but guidelines propose a role for culture and antibiotic sensitivity testing after failure of the second attempt. Meanwhile, data on the geographic distribution of resistance pattern are available and may guide therapeutic decisions with regard to the combination of antibiotics chosen for the individual patients aiming at 100% cure rate in each individual patient.

Efficacy of two triple eradication regimens in children with Helicobacter pylori infection

Triple therapy with bismuth subsalicylate, amoxicillin, metronidazole (BAM) or with omeprazole, amoxicillin, clarithromycin (OAC) has been commonly used for the eradication of Helicobacter pylori infection. We compared the efficacy of these triple therapies in children with H. pylori infection. We retrospectively analyzed results in 233 children with H. pylori infection and treated with OAC (n=141) or BAM (n=92). Overall eradication rates of triple therapy with OAC and BAM were 74% and 85%, respectively, which showed no statistical difference. Our study showed that the triple therapy with BAM was more effective for the first-line eradication of H. pylori infection in Korean children, but has no statistical difference with OAC regimen.

Dynamics of Helicobacter pylori-specific immunoglobulin G for 2 years after successful eradication of Helicobacter pylori infection in an American Indian and Alaska Native population

Helicobacter pylori antibodies were measured over 24 months in American Indian and Alaska Native persons who cleared their infections. Two months after treatment, 82% of H. pylori-negative persons remained seropositive. While there were declines in H. pylori antibodies for 12 months, after 24 months 71% of persons remained seropositive.

Levofloxacin-based triple therapy in first-line treatment for Helicobacter pylori eradication

BACKGROUND

The standard first-line therapies for Helicobacter pylori eradication are based on clarithromycin and amoxicillin or metronidazole. Recent studies suggested levofloxacin as an alternative option for both first-and second-line H. pylori eradication treatment.

AIMS

To compare efficacy and tolerability of two different 7-day standard triple therapies versus 7-day levofloxacin-based triple therapy in first-line treatment for H. pylori infection.

METHODS

Three hundred consecutive H. pylori positive patients were randomized to receive: clarithromycin, amoxicillin, esomeprazole (Group A: N = 100); clarithromycin, metronidazole, esomeprazole (Group B: N = 100); or clarithromycin, levofloxacin, esomeprazole (Group C: N = 100). H. pylori status was rechecked by (13)C urea breath test 6 wk after the end of therapy.

RESULTS

Sixteen out of 300 patients discontinued treatment because of the occurrence of side effects (Group A, 5; Group B, 7; Group C, 4). The eradication rates in intention to treat (ITT) and per protocol (PP) analyses were: Group A, 75% and 79%; Group B, 72% and 77.4%; and Group C, 87% and 90.6%. The eradication rate achieved with levofloxacin-based triple therapy was significantly higher than that with standard therapies in either ITT (87%vs 75%, p <0.05; 87%vs 72%, p <0.01;) or PP analysis (90.6%vs 79%, p <0.05; 90.6 vs 77.4, p <0.05). No difference was found between standard triple therapies. The incidence of side effects was similar among groups.

CONCLUSIONS

A 7-day levofloxacin-based triple therapy can achieve higher H. pylori eradication rates than standard regimens. These data suggest levofloxacin-based regimens can be the most effective in first-line anti-H. pylori therapy, at least in the Italian population.

Diagnosis of Helicobacter pylori infection and determination of clarithromycin resistance by fluorescence in situ hybridization from formalin-fixed, paraffin-embedded gastric biopsy specimens

A reliable diagnostic test for Helicobacter pylori is important in clinical practice and research. The ideal diagnostic test for H. pylori should be sensitive, specific, and cost-effective. Helicobacter pylori resistance to clarithromycin is a common reason for failure of eradication therapy. The aim of this study was to evaluate the fluorescent in situ hybridization (FISH) method to detect H. pylori and determine clarithromycin resistance in formalin-fixed, paraffin-embedded gastric biopsy specimens. One hundred seventeen gastric biopsy specimens from patients with dyspepsia were examined for the presence of H. pylori by conventional culture, FISH, and histopathological methods. A set of fluorescent-labeled oligonucleotide probes binding to either H. pylori 16S rRNA or 23S rRNA sequences were used for FISH analysis. Phenotypic antibiotic susceptibilities of the isolates were tested using the Epsilometer test method (E test). Helicobacter pylori was detected in 70 of 117 biopsy specimens by histopathological examination and FISH, whereas it was detected in 47 specimens by culturing. Histopathology and FISH techniques failed to identify H. pylori in 1 biopsy sample isolated by culture. Clarithromycin resistance was found in 11 of 46 H. pylori isolates using the E test method. All of the phenotypic resistance measurements of isolates were correlated with genotypic clarithromycin resistance. Eleven clarithromycin-resistant strains were identified by FISH. The diagnosis of H. pylori infection and the determination of clarithromycin resistance in formalin-fixed, paraffin-embedded specimens using FISH is promising because it provides a rapid, reliable, and culture-independent diagnosis.

Inhibition of Helicobacter pylori motility by (+)-Syringaresinol from unripe Japanese apricot

A methanol extract from unripe Japanese apricot showed inhibitory activity of Helicobacter pylori motility. Inhibitory compound 1 was isolated and identified as (+)-syringaresinol (1) by spectoroscopic means. (+)-Syringaresinol (1) inhibited >90% of the H. pylori motility at a concentration of 500 microg/ml and the IC50 value was 50 microg/ml.

Tetracycline, metronidazole and amoxicillin-metronidazole combinations in proton pump inhibitor-based triple therapies are equally effective as alternative therapies against Helicobacter pylori infection

BACKGROUND

A proton pump inhibitor (PPI)-based triple therapy with clarithromycin (CAM) and amoxicillin (AMPC) is now a standard regimen for Helicobacter pylori (HP) eradication in Japan. However, the CAM-resistant rate has increased recently and alternative therapies are sorely needed. Therefore the aim of the present study was to evaluate the effectiveness and safety of the PPI-tetracycline (TC)-metronidazole (MNZ) regimen (the PTM regimen) as an alternative therapy in comparison with the PPI-AMPC-MNZ (PAM) regimen.

METHODS

Sixty-four HP-positive patients visiting the HP-eradication clinic in Tokai University Hospital from July 1998 to March 2003 were treated with either PTM or PAM as alternative therapies. The HP eradication was assessed by urea breath test (UBT), HP stool antigen test, or HP culture method more than 2 months after completion of the treatments. The drug resistances against CAM, AMPC, TC, and MNZ were assessed by the agar dilution method.

RESULTS

Fifty-six patients (26 PTM and 30 PAM) completed medication and evaluation of the eradication. The eradication rates of PTM were 82.8% (24/29) and 92.3% (24/26), while those of PAM were 74.3% (26/35) and 89.7% (26/29) by intention-to-treat and per-protocol analysis, respectively. The differences between the regimens were not statistically significant. There were no severe adverse effects observed in either of the regimens. The drug-resistance analyses showed 15 CAM- and one MNZ-resistant cases but no TC or AMPC resistance in the available 25 samples.

CONCLUSION

The PTM and PAM regimens were equally effective and safe as alternative HP eradication therapies. And PTM would be particularly useful in penicillin allergy cases.