[Primary antibiotic resistance of Helicobacter pylori strains and eradication rate according to gastroduodenal disease in Korea]

Helicobacter pylori and Its Antibiotic Heteroresistance: A Neglected Issue in Published Guidelines

"Heteroresistance" is a widely applied term that characterizes most of the multidrug-resistant microorganisms. In microbiological practice, the word "heteroresistance" indicates diverse responses to specific antibiotics by bacterial subpopulations in the same patient. These resistant subpopulations of heteroresistant strains do not respond to antibiotic therapy in vitro or in vivo. Presently, there is no standard protocol available for the treatment of infections caused by heteroresistant Helicobacter pylori in clinical settings, at least according to recent guidelines. Thus, there is a definite need to open a new discussion on how to recognize, how to screen, and how to eliminate those problematic strains in clinical and environmental samples. Since there is great interest in developing new strategies to improve the eradication rate of anti-H. pylori treatments, the presence of heteroresistant strains/clones among clinical isolates of the bacteria should be taken into account. Indeed, increased knowledge of gastroenterologists about the existence of heteroresistance phenomena is highly required. Moreover, the accurate breakpoints should be examined/determined in order to have a solid statement of heteroresistance among the H. pylori isolates. The primary definition of heteroresistance was about coexistence of both resistant and susceptible isolates at the similar gastric microniche at once, while we think that it can be happened subsequently as well. The new guidelines should include a personalized aspect in the standard protocol to select a precise, effective antibiotic therapy for infected patients and also address the problems of regional antibiotic susceptibility profiles.

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.

Favorable outcomes of culture-based Helicobacter pylori eradication therapy in a region with high antimicrobial resistance

BACKGROUND

The eradication rate of Helicobacter pylori has declined, mainly due to antimicrobial resistance. To overcome resistance-associated treatment failure, the efficacy of culture-based, susceptibility-guided therapy was demonstrated as the first-line eradication therapy for H pylori infection.

AIMS

To evaluate the efficacy of culture-based therapy as the first-line eradication therapy in regions with high levels of antimicrobial resistance.

METHODS

Helicobacter pylori-positive patients without previous eradication treatment history were recommended to undergo culture to determine the minimal inhibitory concentration (MIC). If they consented, 7-day clarithromycin-containing PPI triple; 7-day esomeprazole, moxifloxacin, and amoxicillin (MEA) therapy; or 7- or 14-day esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapy were administered based on the agar dilution-determined MIC. Eradication, treatment compliance, and adverse events were examined.

RESULTS

In total, 74 patients were enrolled, and 69 patients completed the protocols. The overall resistance rates to amoxicillin, clarithromycin, metronidazole, and moxifloxacin were 6.7%, 31.0%, 41.8%, and 39.2%, respectively. The patients were allocated to the PPI triple (n = 50), MEA (n = 8) or quadruple (n = 16) therapy. The eradication rate in the intention-to-treat analysis was 93.1% (69 of 74 patients). The eradication rates in the per-protocol analysis were 100.0% (69 of 69 patients). Epigastric pain, nausea, and vomiting were less common than those of other empirical therapies.

CONCLUSIONS

Culture-based, susceptibility-guided therapy is effective first-line eradication therapy, especially in regions with high levels of antimicrobial resistance.

Current Status of the Third-Line Helicobacter pylori Eradication

Antibiotic resistance is growing worldwide, and patients who have failed consecutive 1st- and 2nd-line H. pylori eradication regimens are increasing. Therefore, the role of the bacterial culture with antibiotic susceptibility testing and molecular susceptibility testing is important for avoiding the use of ineffective antibiotics. However, antibiotic susceptibility testing-guided treatment does not necessarily guarantee successful eradication, and there have been mixed results for the effectiveness of a 3rd-line rescue therapy. Therefore, providing patients with pretreatment medication instructions and education is important. It is also crucial to determine the reason of the eradication failure, including host-related factors (poor compliance to eradication regimen, smoking, and cytochrome P450 2C19 genetic polymorphism) or treatment-related factors (inadequate dosage or duration of therapy and gastric acidity), as such factors can be modified for a tailored therapy. Although the indications for H. pylori eradication have widened, patients at a high risk of gastric cancer can gain definitive benefits with a 3rd-line or even 4th-line therapy.

Efficacy of 7-Day and 14-Day Bismuth-Containing Quadruple Therapy and 7-Day and 14-Day Moxifloxacin-Based Triple Therapy as Second-Line Eradication for Helicobacter pylori Infection

BACKGROUND/AIMS

Bismuth-containing quadruple and moxifloxacin-based triple regimens are recommended as second-line therapy for Helicobacter pylori infection. The aim of this study was to compare the efficacy of each regimen.

METHODS

From August 2004 to October 2012, a total of 949 patients (mean age, 54.32±12.08 years; male, 49.4%) who failed H. pylori eradication with a standard triple regimen were included. Patients treated with a bismuth-containing quadruple regimen for 7 and 14 days were designated as 7-BMT and 14-BMT, respectively, and those treated with a moxifloxacin-based triple regimen for 7 and 14 days were designated as 7-MA and 14-MA, respectively. H. pylori eradication was confirmed using the (13)C-urea breath test, rapid urease test or histology.

RESULTS

The eradication rates by 7-BMT, 14-BMT, 7-MA, and 14-MA were 66.4% (290/437), 71.1% (113/159), 53.1% (51/96), and 73.5% (189/257), respectively, by intention-to-treat analysis (ITT) and 76.5% (284/371), 83.8% (109/130), 55.6% (50/90), and 80.6% (187/232), respectively, by per-protocol analysis (PP). The eradication rates were higher in 14-BMT than 7-BMT by the ITT and PP analyses (p=0.277 and p=0.082, respectively). The 14-BMT and 14-MA treatments showed similar efficacies by ITT and PP (p=0.583 and p=0.443, respectively).

CONCLUSIONS

The 7-BMT, 14-BMT, and 14-MA treatments showed similar and suboptimal efficacies. In both regimens, extending the duration of treatment may be reasonable considering the high level of antibiotic resistance in Korea.

The efficacy of moxifloxacin-containing triple therapy after standard triple, sequential, or concomitant therapy failure for Helicobacter pylori eradication in Korea

Background/Aims

Retreatment after initial treatment failure for Helicobacter pylori is very challenging. The purpose of this study was to evaluate the efficacies of moxifloxacin-containing triple and bismuth-containing quadruple therapy.

Methods

A total of 151 patients, who failed initial H. pylori treatment, were included in this retrospective cohort study. The initial regimens were standard triple, sequential, or concomitant therapy, and the efficacies of the two following second-line treatments were evaluated: 7-day moxifloxacin-containing triple therapy (rabeprazole 20 mg twice a day, amoxicillin 1,000 mg twice a day, and moxifloxacin 400 mg once daily) and 7-day bismuth-containing quadruple therapy (rabeprazole 20 mg twice a day, tetracycline 500 mg 4 times a day, metronidazole 500 mg 3 times a day, and tripotassium dicitrate bismuthate 300 mg 4 times a day).

Results

The overall eradication rates after moxifloxacin-containing triple therapy and bismuth-containing quadruple therapy were 69/110 (62.7%) and 32/41 (78%), respectively. Comparison of the two regimens was performed in the patients who failed standard triple therapy, and the results revealed eradication rates of 14/28 (50%) and 32/41 (78%), respectively (p=0.015). The frequency of noncompliance was not different between the two groups, and there were fewer adverse effects in the moxifloxacin-containing triple therapy group (2.8% vs 7.3%, p=0.204 and 25.7% vs 43.9%, p=0.031, respectively).

Conclusions

Moxifloxacin-containing triple therapy, a recommended second-line treatment for initial concomitant or sequential therapy failure, had insufficient efficacy.

A randomised clinical trial of 10-day concomitant therapy and standard triple therapy for Helicobacter pylori eradication

BACKGROUND

As a result of increased resistance to antibiotics, Helicobacter pylori eradication rates using standard triple therapy have been declining.

AIM

To validate the efficacy and tolerability of a concomitant regimen as a first-line treatment for H. pylori infection.

METHODS

A total of 348 naïve H. pylori-infected patients from six hospitals in Korea were randomly assigned to concomitant therapy and standard triple therapy groups. The concomitant regimen consisted of 30 mg of lansoprazole, 1g of amoxicillin, 500 mg of clarithromycin, and 500 mg of metronidazole, twice daily for 10 days. The standard triple regimen consisted of 30 mg of lansoprazole, 1g of amoxicillin, and 500 mg of clarithromycin, twice daily for 10 days.

RESULTS

Concomitant and standard eradication rates were 78.7% (137/174) vs. 70.7% (123/174) by intention-to-treat (p=0.084) and 88.7% (133/150) vs. 78.4% (120/153) by per-protocol (p=0.016), respectively. The two groups were similar with regard to the incidence of adverse events.

CONCLUSIONS

Although 10-day concomitant therapy was validated as a suboptimal treatment option for the treatment of H. pylori infection, this regimen is expected to be a promising starting point in the development of an optimal treatment regimen for H. pylori infection.

[Changes in the eradication rate of conventional triple therapy for Helicobacter pylori infection in Korea]

Although, the prevalence of Helicobacter pylori infection in Korea has declined owing to the eradication therapy, recent seropreva-lence of H. pylori infection is still reported to be as high as 54.4%. Until now, "standard regimen" for eradication of H. pylori has been conventional triple therapy consisting of proton pump inhibitor, amoxicillin, and clarithromycin. However, with the increase in antibiotic resistance, especially against clarithromycin, the eradication rate of conventional triple therapy has steadily declined during the past 13 years in Korea. Present eradication rate of standard triple therapy is reported to be less than 80%, which is the Maginot line of efficacy for the currently available regimen. Therefore, new first line eradication regimen is needed to enhance the eradication rate of H. pylori infection.

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.

Meta-analysis of first-line triple therapy for helicobacter pylori eradication in Korea: is it time to change?

Proton pump inhibitor (PPI)-based triple therapy consisting of PPI, amoxicillin, and clarithromycin, is the recommended first-line treatment for Helicobacter pylori infection. However, the eradication rate of triple therapy has declined over the past few decades. We analyzed the eradication rate and adverse events of triple therapy to evaluate current practices in Korea. A comprehensive literature search was performed up to August 2013 of 104 relevant studies comprising 42,124 patients. The overall eradication rate was 74.6% (95% confidence interval [CI], 72.1%-77.2%) by intention-to-treat analysis and 82.0% (95% CI, 80.8%-83.2%) by per-protocol analysis. The eradication rate decreased significantly from 1998 to 2013 (P < 0.001 for both intention-to-treat and per-protocol analyses). Adverse events were reported in 41 studies with 8,018 subjects with an overall incidence rate of 20.4% (95% CI, 19.6%-21.3%). The available data suggest that the effectiveness of standard triple therapy for H. pylori eradication has decreased to an unacceptable level. A novel therapeutic strategy is warranted to improve the effectiveness of first-line treatment for H. pylori infection in Korea.

Non-microbial approach for Helicobacter pylori as faster track to prevent gastric cancer than simple eradication

Although the International Agency for Research on Cancer declared Helicobacter pylori (H. pylori) as a definite human carcinogen in 1994, the Japanese Society for Helicobacter Research only recently (February 2013) adopted the position that H. pylori infection should be considered as an indication for either amelioration of chronic gastritis or for decreasing gastric cancer mortality. Japanese researchers have found that H. pylori eradication halts progressive mucosal damage and that successful eradication in patients with non-atrophic gastritis most likely prevents subsequent development of gastric cancer. However, those who have already developed atrophic gastritis/gastric atrophy retain potential risk factors for gastric cancer. Because chronic perpetuated progression of H. pylori-associated gastric inflammation is associated with increased morbidity culminating in gastric carcinogenesis, a non-microbial approach to treatment that provides long-term control of gastric inflammation through nutrients and other interventions may be an effective way to decrease this morbidity. This non-microbial approach might represent a new form of prerequisite "rescue" therapy that provides a quicker path to the prevention of gastric cancer as compared to simple eradication.

Levofloxacin, Metronidazole, and Lansoprazole Triple Therapy Compared to Quadruple Therapy as a Second-Line Treatment of Helicobacter pylori Infection in Korea

BACKGROUND/AIMS

Several rescue therapies have been recommended to eradicate Helicobacter pylori infection in patients with a failure of first-line eradication therapy, but they still fail in more than 20% of cases. The aim of this study was to evaluate the efficacy and safety of levofloxacin, metronidazole, and lansoprazole (LML) triple therapy relative to quadruple therapy as a second-line treatment.

METHODS

In total, 113 patients who failed first-line triple therapy for H. pylori infection were randomly assigned to two groups: LML for 7 days and tetracycline, bismuth subcitrate, metronidazole and lansoprazole (quadruple) for 7 days.

RESULTS

According to intention-to-treat analysis, the infection was eradicated in 38 of 56 patients (67.9%) in the LML group and 48 of 57 (84.2%) in the quadruple group (p=0.042). Per-protocol analysis showed successful eradication in 38 of 52 patients (73.1%) from the LML group and 48 of 52 (92.3%) from the quadruple group (p=0.010). There were no significant differences in the adverse effects in either treatment group.

CONCLUSIONS

LML therapy is less effective than quadruple therapy as a second-line treatment for H. pylori infection. Therefore, quadruple therapy should be considered as the primary second-line strategy for patients experiencing a failure of first-line H. pylori therapy in Korea.

Clinical outcomes of two-week sequential and concomitant therapies for Helicobacter pylori eradication: a randomized pilot study

BACKGROUND

The eradication rate with PPI-based standard triple therapy for Helicobacter pylori infection has fallen considerably. One recent innovation is sequential therapy with PPI and three antibiotics, but the complexity of this regimen may reduce its usability. Concomitant administration of nonbismuth quadruple drugs (concomitant therapy) is also an effective treatment strategy. To investigate which regimen is a reasonable choice for Korean population, we performed two pilot studies with sequential and concomitant therapies.

METHODS

A total of 164 patients with proven H. pylori infection randomly received 14 days of sequential (n = 86) or concomitant (n = 78) therapies. The sequential group received 20 mg rabeprazole and 1 g amoxicillin (first week), followed by 20 mg rabeprazole, 500 mg clarithromycin, and 500 mg metronidazole (second week). The concomitant group received 20 mg rabeprazole, 1 g amoxicillin, 500 mg clarithromycin, and 500 mg metronidazole for 2 weeks. All drugs were administered BID. Helicobacter pylori status was confirmed 4 weeks later, after completion of treatment by (13) C-urea breath test.

RESULTS

The intention-to-treat and per-protocol eradication rates were 75.6% (95% CI, 66.3-84.9) and 76.8% (95% CI, 67.1-85.5) in the sequential group, and 80.8% (95% CI, 71.8-88.5) and 81.3% (95% CI, 71.6-90.7) in the concomitant group. There were no significant between-group differences, in regard to the eradication rates, compliance, or side effects. The most common side effects were bitter taste, epigastric soreness, and diarrhea.

CONCLUSIONS

Two-week concomitant and sequential therapies showed suboptimal efficacies. However, considering high antibiotics resistance, either of these two regimens may be a reasonable choice for Korean population.

Rifaximin Plus Levofloxacin-Based Rescue Regimen for the Eradication of Helicobacter pylori

Background/Aims

This study assessed the efficacy of a rifaximin plus levofloxacin-based rescue regimen in patients that had failed both triple and quadruple standard regimens for the eradication of Helicobacter pylori.

Methods

We treated patients for H. pylori between August 2009 and April 2011. The triple regimen consisted of combined treatment with amoxicillin, clarithromycin, and pantoprazole for 1 week. For failed cases, a quadruple regimen of tetracycline, metronidazole, bismuth dicitrate, and lansoprazole for 1 week was administered. The rescue regimen for persistently refractory cases was rifaximin 200 mg t.i.d., levofloxacin 500 mg q.d., and lansoprazole 15 mg b.i.d. for 1 week.

Results

In total, 482 patients were enrolled in this study. The eradication rates associated with the first and second regimens were 58% and 60%, respectively. Forty-seven out of 58 patients who failed with the second-line regimen received rifaximin plus levofloxacin-based third-line therapy. The eradication rate for the third regimen was 65%. The cumulative eradication rates were 58%, 85%, and 96% for each regimen, respectively.

Conclusions

A rifaximin plus levofloxacin-based regimen could be an alternative rescue therapy in patients with resistance to both triple and quadruple regimens for the eradication of H. pylori.

Treatment of Helicobacter pylori infection 2012

Helicobacter pylori resistance rates to antibiotics vary in different countries and even in different regions of the same country. Choice of treatment is strongly dependent on antibiotic resistance rates. In some countries, triple therapy with a proton-pump inhibitor, amoxicillin, and clarithromycin is still the best option, but eradication results fall short of what would be desired (90-95%) in countries with clarithromycin resistance >20%, bismuth-containing quadruple therapy, or nonbismuth sequential or concomitant therapies may then be the preferred option. Newer antibiotic regimens are awaited. Vaccination would be the best option, especially for developing countries, but little progress has been made in designing a vaccine.