Geographic map and evolution of primary Helicobacter pylori resistance to antibacterial agents

In vitro activity of delafloxacin against clinical levofloxacin-resistant Helicobacter pylori isolates

BACKGROUND

Increasing antibiotic resistance in Helicobacter pylori necessitates research on new active molecules. In 2017, delafloxacin, a new fluoroquinolone with chemical properties of activity under acidic conditions, was approved for treatment of community-acquired bacterial pneumonia and acute bacterial skin and soft-tissue infections. Mutations in gyrA are responsible for fluoroquinolone resistance, but certain clinical isolates of H. pylori appear to display a dual phenotype: resistance to levofloxacin associated with very low delafloxacin MICs.

OBJECTIVES

To estimate epidemiological cut-off (ECOFF) values and to identify mutations in the gyrA gene, specific to FQ resistance, without increasing the MICs of delafloxacin.

METHODS

Clinical strains (n = 231) were collected in the bacteriology laboratory of Poitiers University Hospital over a 2 year period to determine the ECOFF of delafloxacin. Retrospectively, 101 clinical strains with an levofloxacin-resistant phenotype (MIC > 1 mg/L) were selected from 2018 to 2022 for delafloxacin MIC determination and QRDR (gyrA) sequencing.

RESULTS

The estimated ECOFF of delafloxacin was ≤0.125 mg/L. No H. pylori isolate showed a levofloxacin-sensitive phenotype with a delafloxacin MIC of >0.125 mg/L. Among the levofloxacin-resistant H. pylori isolates, 53.5% had delafloxacin MICs of ≤0.125 mg/L. The N87I mutation was associated with dual levofloxacin/delafloxacin resistance (P < 0.001) in contrast to the N87K and D91N mutations (P > 0.05). Mutations D91G and D91Y were not associated with a delafloxacin resistance phenotype (P > 0.05).

CONCLUSIONS

Delafloxacin seems to be a therapeutic alternative for levofloxacin-resistant strains with greater in vitro activity. However, further clinical/biological investigations are required to determine its efficacy in H. pylori eradication.

Global Primary Antibiotic Resistance Rate of Helicobacter pylori in Recent 10 years: A Systematic Review and Meta-Analysis

INTRODUCTION

Due to irregular antibiotic use, the rate of antibiotic resistance to Helicobacter pylori (H. pylori) is increasing and varies from region to region. Therefore, for the purpose of further clarifying the changes in antibiotic resistance rates nowadays, we conducted a systematic review and meta-analysis to update and assess the 10-year trend of primary H. pylori antibiotic resistance rate to the commonly prescribed antibiotics worldwide.

MATERIALS AND METHODS

According to the PRISMA statement, we systematically searched electronic databases for studies that assessed rates of H. pylori resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, or tetracycline published from 2013 to 2023. AHRQ was adopted to estimate methodological quality and publication bias in the included studies, and statistical analysis was performed using Stata 17.0.

RESULTS

We identified 163 studies, comprising 47,002 isolates from 36 countries. The meta-analysis showed that the primary antibiotic resistance rate of H. pylori varied widely among antibiotics. Subgroup analysis showed higher rates of antibiotic resistance in the adult population than in children, and a general trend of increased resistance was observed from 2013 to 2023. There was considerable heterogeneity (I2 > 75%) among all analyses, which may be due to high variability in resistance rates across the global regions.

CONCLUSIONS

Resistance of H. pylori to antibiotics has reached alarming levels worldwide, which has a great effect on the efficacy of treatment. Local surveillance networks are required to select appropriate eradication regimens for each region.

Helicobacter pylori Secondary Antibiotic Resistance after One or More Eradication Failure: A Genotypic Stool Analysis Study

Helicobacter pylori (H. pylori) antibiotic resistance is the leading cause for unsuccessful eradication therapy. After one or more failures, the chance of encountering secondary antibiotic resistance increases. The aim of this study was to characterize genotypic secondary resistance in a cohort of southern Italian H. pylori patients with at least one previous failure. Such patients collected stool samples using a dedicated kit (THD fecal testTM), and bacterial DNA was extracted and amplified using RT-PCR. Resistance to clarithromycin, amoxicillin, metronidazole, levofloxacin, and tetracycline was assessed using a high-resolution melting curve. We enrolled 50 patients. A total of 72% of patients failed one previous antibiotic course, 16% failed two, 10% failed three, and 2% failed four. The rate of secondary antibiotic resistance was 16% for clarithromycin, 18% for metronidazole, 14% for amoxicillin, 14% for levofloxacin, and 2% for tetracycline. Among the eight clarithromycin-resistant patients, five (62.5%) previously received a clarithromycin-based regimen. The same rate was 33.3% (3/9) for metronidazole. The only tetracycline-resistant patient had received Pylera. In conclusion, our data seem to show that, even though secondary resistance is not very high, resistance to clarithromycin could be very likely related to previous exposure to this antibiotic.

Novel Information Regarding the Treatment of Helicobacter pylori Infection: A Systematic Review and Meta-analysis of Randomized Clinical Trials

OBJECTIVE

Helicobacter pylori infects at least 50% of the world's human population. The current study aimed to assess and compare the efficacy of triple versus quadruple therapy.

METHODS

Randomized clinical trials (RCTs) consisting of triple and quadruple therapy were identified through electronic and manual searches in the national and international online databases (IsI, Magiran, Embase, PubMed, and Scopus). The random-effects model was applied to pool analysis. Funnel plots and the Egger test were used to examine publication bias.

RESULTS

After a detailed review of the selected articles, 80 RCTs were included in the meta-analysis; it was based on using triple and quadruple therapy as the first and second-line treatment. The results showed that quadruple therapy in the first-line treatment had a higher eradication rate than triple therapy. Overall, the eradication rate with triple therapy was 74% (95% CI, 71%-77%) for intention-totreat (ITT) analysis and 80% (95% CI, 77%-82%) for per-protocol (PP) analysis. Generally, the eradication rate with quadruple therapy was 82% (95% CI, 78.0%-86.0%) for ITT analysis and 85% (95% CI, 82.0%-89.0%) for PP analysis. The analysis also revealed that quadruple therapy was more effective for 7 or 10 days.

CONCLUSION

The current study results demonstrated that quadruple therapy has better effectiveness than triple therapy as the first-line treatment; however, in the second-line treatment, the effectiveness of quadruple and triple regimens is almost similar. The effectiveness of quadruple therapy in the Asian population was found to be slightly higher than that of triple therapy, while this difference was considerably higher in the European population.

Global analysis on the mutations associated with multidrug-resistant urogenital mycoplasmas and ureaplasmas infection: a systematic review and meta-analysis

BACKGROUND

The emergence of multidrug-resistant (MDR) strains of genital pathogens, notably Mycoplasma genitalium and Ureaplasma spp., constitutes a significant global threat today. The present study aimed to evaluate the prevalence and trend of changes in MDR mycoplasma and ureaplasma strains.

METHODS

An exhaustive search was performed across the ISI Web of Science, PubMed, Scopus, ScienceDirect, and Google Scholar databases to accumulate relevant studies without restrictions until April 2023. We used event rate and corresponding 95% confidence intervals to determine the frequency of resistance-related mutations and examine the trend of antibiotic resistance changes.

RESULTS

The data from 27 studies, including 24,662 patients across 14 countries, were evaluated. Out of the total studies, 20 focused on M. genitalium infections, and five on Ureaplasma spp. The frequency of resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones in clinical strains of M. genitalium was 43.5%, 13.1%, and 18.6%, respectively. The prevalence of M. genitalium strains with double resistance and MDR was 11.0% and 17.4%, respectively. The incidence of both double-drug-resistant and MDR strains was higher in the World Health Organization (WHO) Western Pacific Region than in European and American populations. For Ureaplasma strains, resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones were 40.8%, 25.7%, and 90.3%, respectively. The rate of antibiotic resistance was higher in the African population compared to the European and WHO Western Pacific Regions. The rate of MDR Ureaplasma infections was 13.2%, with a higher incidence in the African population compared to the WHO Western Pacific and European regions.

CONCLUSION

The proliferation and spread of MDR Mycoplasma and Ureaplasma strains present a significant public health challenge. The situation is indeed alarming, and the rising trend of MDR M. genitalium and MDR Ureaplasma infections suggests that therapies involving macrolides and fluoroquinolones may become less effective.

Helicobacter pylori Treatment Regimen Selection and Eradication Rates Across Department of Defense Patients for Fiscal Years 2016-2018

INTRODUCTION

The objective of this study was to measure the number of treatment successes and failures of various Helicobacter pylori treatment regimens among DoD beneficiaries.

MATERIALS AND METHODS

This was a retrospective cross-sectional study of all adult DoD beneficiaries with H. pylori diagnosis, treatment, and eradication testing from October 2015 to September 2018. All stool antigen testing, urea breath test, and immunoglobulin G serologies were identified. Patients were excluded if they did not have a positive test, did not have treatment, or did not have eradication testing.

RESULTS

In total, 20,548 H. pylori diagnostic tests were performed over the study period. A total of 1,592 non-active duty and 374 active duty patients were diagnosed with H. pylori, were treated, and had eradication testing. The best performing regimens were tetracycline-based bismuth quadruple therapy and tinidazole-based clarithromycin triple therapy with eradication rates of 85% and 82%, respectively. Clarithromycin triple therapy was the most prescribed (63.9% of all regimens included in analysis). Of the 1,592 non-active duty and 374 active duty patients, 75.5% (1,202) and 70.6% (264) cleared the infection with treatment, respectively (P = 0.0449). Although trends were identified in differences in geographic eradication rates, none of these achieved the threshold of significance.

CONCLUSIONS

This is the largest and most geographically widespread H. pylori treatment efficacy study in the USA over 20 years. None of the treatment regimens (when used in over five patients) achieved an eradication rate greater than 90%, but tetracycline-based bismuth quadruple therapy performed best among all regimens and populations. Eradication rates were lower in the active duty populations, with no treatment regimen achieving an eradication rate greater than 80%.

Genotypic detection of metronidazole and clarithromycin resistance in dyspeptic patients with helicobacter pylori

In Egypt, antibiotic sensitivity analysis for Helicobacter pylori is not routinely performed. We aimed to identify the clarithromycin and metronidazole resistance directly from gastric biopsies for better guide treatment regimens. This cross-sectional descriptive study included 75 adult dyspeptic patients referred to the upper endoscopy unit in Suez Canal University Hospital, Ismailia, Egypt. Gastric biopsies were taken for rapid urease test (RUT) and cultured on brucella agar with antibiotic supplements. Genomic DNA was extracted directly from the specimen, and PCR was performed for direct detection of H. pylori. Also, to explore clarithromycin and metronidazole resistance, mutations in the 23S rRNA gene and the rdxA gene were investigated. We found that 60 samples were positive to RUT (80%), and only 4 samples were positive by culture. UreC gene was detected in 45 specimens. Meanwhile, 26 isolates were contained mutations at positions 2142 and 2143. Amplification of the metronidazole rdx gene was performed by conventional PCR. Out of 45 isolates, DNA sequence analysis of PCR product showed the wild type (ACA) in 9 isolates, while the mutant type (ATA) was detected in 28 isolates. We found a significant proportion of clarithromycin and metronidazole resistance among H. pylori infected patients in our region.

Development and Validation of Multiplex Quantitative PCR Assay for Detection of Helicobacter pylori and Mutations Conferring Resistance to Clarithromycin and Levofloxacin in Gastric Biopsy

Aims and Objectives

More than half of the world's population is infected with Helicobacter pylori, which can cause chronic gastritis. WHO has regarded clarithromycin-resistant H. pylori as a high priority pathogen. Hence, accurate diagnosis and detection of clarithromycin- and levofloxacin-resistant H. pylori strains is essential for proper management of infection. The objective of this study was to develop and optimize multiplex quantitative PCR assay for detection of mutations associated with clarithromycin and levofloxacin resistance in H. pylori directly from the gastric biopsies.

Materials and Methods

Specific primers and probes were designed to amplify ureA and mutations in 23S rRNA and gyrA genes. Singleplex and triplex qPCR assays were optimized and the assay's sensitivities and specificities were determined. The optimized multiplex qPCR assay was performed on 571 gastric biopsies.

Results

In this study, 14.7% (84/571) of the gastric biopsies were positive for H. pylori by conventional methods and 23.8% (136/571) were positive by the ureA-qPCR with 96.4% sensitivity and 88.5% specificity, while the +LR and -LR were 8.72 and 0.04, respectively. The ureA-positive samples (n=136) were subjected to multiplex qPCR which detected A2142G and A2143G mutations in the 23S rRNA gene (20.6%, 28/136) conferring clarithromycin resistance and gyrA mutations N87K, N87I, D91N, and D91Y (11.8%, 16/136) leading to levofloxacin resistance. The sensitivity and specificity of qPCR of 23S rRNA gene were 100% and 98.7%, respectively, while 100% and 99.8% for qPCR of gyrA, respectively.

Conclusion

The effectiveness of this qPCR is that it is sensitive in detecting low bacterial load and will help in timely detection of clarithromycin- and levofloxacin-resistant strains, especially in case of mixed infections. Since it is culture independent, it can inform clinicians about antibiotics to be included in the first-line therapy, thereby improving the management of H. pylori infection at a much greater pace.

Second-Line Bismuth-Containing Quadruple Therapy for Helicobacterpylori Infection: A 12-Year Study of Annual Eradication Rates

Background: Bismuth-containing quadruple therapy (BQT) consisting of a proton-pump inhibitor (PPI), bismuth, metronidazole and tetracycline is recommended as a second-line treatment for Helicobacter pylori (H. pylori) infection when PPI-based standard triple therapy (STT) consisting of a PPI, amoxicillin and clarithromycin is unsuccessful. The purpose of this study was to analyze the long-term results of BQT as a second-line therapy to determine its effectiveness. Methods: This study included 643 subjects who failed first-line STT and received 7 or 10–14 days of BQT as a second-line therapy. We retrospectively analyzed the annual H. pylori eradication rates, demographic factors and adverse events. Results: The overall eradication rates by intention-to-treat (ITT) and per-protocol (PP) analyses were 80.7% (519/643) and 93.3% (519/556), respectively. By PP analysis, the eradication rates for 2008–2011, 2012–2015, and 2016–2019 were 93.3%, 91.0%, and 96.4%, respectively (p = 0.145). There were no significant differences between the 7-day group and the 10–14-day group in both the ITT (79.7% vs. 86.0%, p = 0.148) and the PP analyses (92.7% vs. 96.6%, p = 0.187). A multivariate analysis showed that current smoking was associated with eradication failure. Eighty-nine subjects (16.0%) suffered adverse events, mainly gastrointestinal symptoms, but only six cases were severe. Conclusions: BQT as a second-line therapy is an effective treatment for H. pylori. Treatment for 10–14 days showed a higher eradication rate compared with a 7-day regimen, but not significantly.

[Impact of the use of molecular techniques (PCR) on detection and eradication success against Helicobacter pylori]

INTRODUCTION

Helicobacter pylori (H. pylori) infection affects more than 50% of the world population. Increased antibiotic resistance is the main cause of treatment failure. The main objective was to analyze the eradication success after the application of the new ESPGHAN treatment recommendations and the introduction of PCR as a direct diagnosis technique, describe the evolution of the local pattern of antibiotic resistance, and assess the cost-effectiveness of PCR application, isolated or in conjunction with culture as a diagnostic strategy.

PATIENTS AND METHODS

retrospective descriptive study of all microbiological isolates of H. pylori in 2013-2019 in our center, by comparing the percentage of resistance and eradication success between the periods 2013-2016 and 2017-2019. Cost-effectiveness study of direct diagnostic tests, comparing 3 different options: culture and PCR; only culture; PCR only.

RESULTS

192 patients were included, 98 were detected by culture (2013-2016) and 94 by culture and / or PCR (2017-2019). Antibiotic treatment was established in 153 patients, 90 in the first period (2011 ESPGHAN guidelines: eradication percentage 62.2%), 63 in the second (2017 ESPGHAN guidelines: eradication percentage: 73%). An increase in resistance to clarithromycin was observed, going from 16.3% (n=16) in the first period, to 53.2% (n=48) in 2017-2019 (98% detected by PCR, 60% by culture). There were no differences in the rest of antibiotic resistances. The isolated PCR application presented a cost-effectiveness analysis ratio (CEAR) of 71.91, compared to 92.16 for the culture and 96.35 for the culture and PCR combined.

CONCLUSIONS

the application of the ESPGHAN 2017 guidelines achieved greater eradication success, although less than that observed in previous publications, without reaching the target of at least 90%. An increase in resistance to macrolides was observed, without being able to discriminate whether it is a real increase or a greater diagnostic sensitivity of molecular techniques, with the isolated request for PCR being the most cost-effective strategy.

Best Helicobacter pylori Eradication Strategy in the Era of Antibiotic Resistance

Antibiotic resistance is the major reason for Helicobacter pylori treatment failure, and the increasing frequency of antibiotic resistance is a challenge for clinicians. Resistance to clarithromycin and metronidazole is a particular problem. The standard triple therapy (proton pump inhibitor, amoxicillin, and clarithromycin) is no longer appropriate as the first-line treatment in most areas. Recent guidelines for the treatment of H. pylori infection recommend a quadruple regimen (bismuth or non-bismuth) as the first-line therapy. This treatment strategy is effective for areas with high resistance to clarithromycin or metronidazole, but the resistance rate inevitably increases as a result of prolonged therapy with multiple antibiotics. Novel potassium-competitive acid blocker-based therapy may be effective, but the data are limited. Tailored therapy based on antimicrobial susceptibility test results is ideal. This review discussed the current important regimens for H. pylori treatment and the optimum H. pylori eradication strategy.

Management of antibiotic-resistant Helicobacter pylori infection: current perspective in Iran

Helicobacter pylori is a common gastric bacterial pathogen implicated in the pathogenesis of many digestive tract disorders. H. pylori infection prevalence has been reported alarmingly in Iran. A plethora of studies have been conducted to evaluate the efficiency of first-line and second-line eradication attempts in patients diagnosed with H. pylori infections in Iran. The present study, was evaluated the efficacy of first-line and second-line therapy in H. pylori infections in Iran. We aimed to consider the literature review of the various library and electronic databases (Science Direct, PubMed, and Google Scholar) until 2020. The frequency of bacterial resistance to tetracycline, ampicillin, trimethoprim, erythromycin, ofloxacin, and metronidazolewas found to be high in Iran, while the most effective antibiotics were clarithromycin, rifampin, rifampicin, tetracycline, amoxicillin, ciprofloxacin, levofloxacin, moxifloxacin, and azithromycin. The therapeutic choice for H. pylori eradication in Iran could be quadruple therapy using two antibiotics amoxicillin and metronidazole/clarithromycin for the first-line regimen, and a combination of furazolidone plus tetracycline/amoxicillin and bismuth plus proton pump inhibitor for the second-line regimen. Due to increased antibiotic resistance in our region, empirical therapy must be replaced by more targeted treatment based on antimicrobial drug resistance profiles obtained from patients. Although we limited our investigation on the H. pylori eradication regimens in Iran, the results can be generalized to any region as long as the patterns of resistance are the same.

A Comparison between 10-day and 12-day Concomitant Regimens for Helicobacter Pylori Eradication: A Randomized Clinical Trial

BACKGROUND

Helicobacter pylori (H. pylori) infection is one of the most common bacterial infections worldwide, which is associated with peptic ulcer disease and gastric cancer. In this study, we compared the efficacy of 10-day versus 12-day concomitant therapy as the first-line treatment for H. pylori eradication in Iran.

METHODS

218 patients with peptic ulcer disease and naïve H. pylori infection, were randomly divided into two groups to receive either 10-day or 12-day concomitant regimens, composed of pantoprazole 40 mg, amoxicillin 1000 mg, clarithromycin 500 mg, and metronidazole 500 mg, all given twice daily. Eight weeks after treatment, H. pylori eradication was assessed by 14C- urea breath test. The trial was registered in the Iranian Registry of Clinical Trials (code: IRCT20170521034070N2).

RESULTS

212 patients completed the study. According to the intention to treat analysis, the eradication rates were 83.6% (95% CI: 76.6-90.5) and 88.8% (95% CI: 82.8-94.7) in 10-day and 12-day concomitant therapy groups, respectively (p = 0.24). Per-protocol eradication rates were 85.9% (95% CI: 79.3–92.4) and 92.6% (95% CI: 87.6–97.5), respectively (p = 0.19). The rates of severe side effects were not statistically different between the two groups (3.6% vs. 8.1%; p = 0.428).

CONCLUSION

12-day concomitant therapy could achieve ideal eradication rates by both intention to treat and perprotocol analyses. In order to reduce the cost of drugs and the rate of adverse effects of therapy, among 10-day and 12day regimens, 12-day concomitant therapy seems to be a good alternative to 14-day concomitant therapy that has been suggested by international guidelines.

Bovine lactoferrin enhances the efficacy of levofloxacin-based triple therapy as first-line treatment of Helicobacter pylori infection: an in vitro and in vivo study

Objectives

To evaluate the in vitro antimicrobial/antivirulence action of bovine lactoferrin and its ability to synergize with levofloxacin against resistant Helicobacter pylori strains and to analyse the effect of levofloxacin, amoxicillin and esomeprazole with and without bovine lactoferrin as the first-line treatment for H. pylori infection.

Methods

The bovine lactoferrin antimicrobial/antivirulence effect was analysed in vitro by MIC/MBC determination and twitching motility against six clinical H. pylori strains and a reference strain. The synergism was evaluated using the chequerboard assay. The prospective therapeutic trial was carried out on two separate patient groups, one treated with esomeprazole/amoxicillin/levofloxacin and the other with esomeprazole/amoxicillin/levofloxacin/bovine lactoferrin. Treatment outcome was determined with the [¹³C]urea breath test.

Results

In vitro, bovine lactoferrin inhibited the growth of 50% of strains at 10 mg/mL and expressed 50% bactericidal effect at 40 mg/mL. The combination of levofloxacin and bovine lactoferrin displayed a synergistic effect for all strains, with the best MIC reduction of 16- and 32-fold for levofloxacin and bovine lactoferrin, respectively. Bovine lactoferrin at one-fourth MIC reduced microbial motility significantly for all strains studied. In the in vivo study, 6 of 24 patients recruited had treatment failure recorded with esomeprazole/amoxicillin/levofloxacin (75% success, 95% CI 57.68%–92.32%), and in the group with esomeprazole/amoxicillin/levofloxacin/bovine lactoferrin, 2 out of 53 patients recruited had failure recorded (96.07% success, 95% CI 90.62%–101.38%).

Conclusions

Bovine lactoferrin can be considered a novel potentiator for restoring susceptibility in resistant H. pylori strains. Bovine lactoferrin added to a triple therapy in first-line treatment potentiates the therapeutic effect.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Helicobacter pylori antibiotic resistance and correlation with cagA motifs and homB gene

Objectives: Helicobacter pylori (H. pylori) infection caused by antibiotic-resistant strains represents a major public health threat that aggressively promotes gastric cancer progression. Antibiotic resistance evaluation is immensely important to counteract its emergence. Here we merely determine the prevalence of antibiotic resistance in H. pylori isolates and its correlation with cagA motifs and the homB gene. Methods: The antibiotic resistance pattern was investigated on 128 H. pylori isolated strains utilizing the disk diffusion method and study the correlation between it and the presence of pathogenic genes, cagA EPIYA motifs and homB gene, were accurately detected using the PCR. Results: The resistance rates to four antibiotics were 70.1% for metronidazole, 35.5% for amoxicillin, 7.2% for clarithromycin and 8.2% for tetracycline. Resistance phenotypes were separated into two groups, single resistance (63.2%) and multi-resistance (12.5%). The prevalence of cagA-ABCC resistant strains and homB⁺ resistant strains was significantly higher in cancer (p = 0.04 and p = 0.01, respectively) than those of other diseases. The prevalence of cagA-homB ⁺ resistance strains was 21.8% and had a significant correlation with PUD. A significant relationship was observed between amoxicillin resistant rate with ABC-homB (p = 0.0006). Conclusion: The Resistance rate to selected antibiotics in Shiraz is higher than years ago. The presence of cagA-homB ⁺ is associated with antibiotic resistance and also homB can be used as a marker to antibiotic resistance status prediction in H. pylori isolated in this area.

Sociodemographic characteristics and clinical risk factors of Helicobacter pylori infection and antibiotic resistance in the Eastern Black Sea region of Turkey

BACKGROUND/AIMS

The aim of this study was to assess the clinical and sociodemographic risk factors of Helicobacter pylori infection and antibiotic resistance in the eastern Black Sea region of Turkey.

MATERIALS AND METHODS

In total, 344 patients with dyspeptic symptoms who completed an extended questionnaire were enrolled in the study. Diagnosis of H. pylori infection was made by rapid urease test, histopathological investigation, and culture. Susceptibility of H. pylori strains was assessed by agar dilution (amoxicillin, tetracycline, metronidazole, levofloxacin) and E-test (clarithromycin) methods.

RESULTS

The H. pylori positivity rate was 40.4% (139/344). Logistic regression analysis indicated that age and the presence of duodenal ulcer were independent risk factors associated with H. pylori positivity (odds ratio (OR): 0.96, 95% CI: 0.93-0.99, p=0.013; OR: 5.42, 95% CI: 1.96-14.98, p=0.001, respectively). Of 104 H. pylori-positive cultures, 43 strains (41%) were susceptible to all antibiotics, whereas 61 (59%) were resistant to at least one antibiotic. H. pylori resistance rates were 34% for levofloxacin, 31.1% for metronidazole, 28.2% for clarithromycin, 2.9% for amoxicillin, and 1% for tetracycline. Logistic regression analysis indicated that previous use of clarithromycin was the only independent risk factor for H. pylori resistance (OR: 6.25, 95% CI: 1.59-24.52, p=0.009).

CONCLUSION

An understanding of the risk factors for H. pylori positivity and antibiotic resistance in an extended anamnesis may affect treatment choice and facilitate H. pylori eradication. In regions where antibiotic resistance rates are elevated, performing antibiotic susceptibility tests may lead to effective eradication treatment.

Prevalence of Infection and Antibiotic Susceptibility of Helicobacter pylori: An Evaluation in Public and Private Health Systems of Southern Chile

Helicobacter pylori colonizes half of the human population. Age, ethnicity, and socioeconomic status are factors that influence the prevalence of the infection. This is important in southern Chile, one of the most unequal regions in the world, where a significant difference in the health access of the population occurs due to the existence of two competing health systems. Moreover, in the last few years, current protocols of H. pylori eradication have shown high rates of resistance with reduced therapeutic efficacy. This study reported the epidemiology of infection and attempted to identify divergent points among the population beneficiaries of the two health care schemes in southern Chile. Biopsies from public (n = 143) and private (n = 86) health systems were studied. At the same time, clinical and sociodemographic factors were evaluated. H. pylori strains were obtained from gastric biopsies for culture and molecular testing. Antibiotic susceptibility was determined by the agar dilution method. Differences about ethnicity, rural residence, and education (p ≤ 0.05) were observed between beneficiaries of the two health systems. The prevalence of H. pylori was 45%, with no significant differences regardless of the socioeconomic conditions. The only identified risk factor associated with H. pylori infection was Mapuche ethnicity (OR (odds ratio) = 2.30). H. pylori showed high resistance rates, particularly against clarithromycin (40%), levofloxacin (43.1%), and metronidazole (81.8%). This study highlighted the importance of Mapuche ancestry as a risk factor in southern Chile and emphasized the need to search for new eradication strategies as well as further studies evaluating therapeutic efficacy.

Pylera® plus ranitidine vs Pylera® plus esomeprazole in first-line treatment of Helicobacter pylori infection: Two pilot studies

BACKGROUND

Several studies have shown that Pylera^® (three-in-one capsules containing 140 mg bismuth potassium subcitrate, 125 metronidazole, and tetracycline 125 mg) in association with omeprazole or esomeprazole is a good option in the treatment of Helicobacter pylori infection. In particular, the adjunction of a PPI to Pylera^® may be useful to overcome metronidazole resistance. However, omeprazole and its derivatives can promote greater bismuth absorption and enhance its toxicity. The H2 receptor antagonist (H2RA) ranitidine seems to induce less bismuth absorption and as a consequence less systemic toxicity.

AIM

To evaluate whether Pylera^® in combination with esomeprazole or with ranitidine is equally effective in the treatment of H. pylori infection.

MATERIAL AND METHODS

Two separate groups of patients were treated simultaneously. One group was treated with Pylera^® three capsules qid plus esomeprazole 40 mg bid for 10 days (group A), and the other group was treated with Pylera^® three capsules qid plus ranitidine 300 mg bid for 10 days (group B). H. pylori eradication was defined as a negative result in ¹³ C urea breath test performed at least 8 weeks after the end of treatment with a delta-over-baseline value less than 5.

RESULTS

Thirty-two patients were recruited for group A and thirty-three patients in group B. Eradication rates were 93.7% (30/32) and 90.9% (30/33), respectively, at intention-to-treat analysis, and 96.6% (29/30) and 93.3% (28/30), respectively, at per-protocol analysis. Adverse events occurred in 26 patients and led to the suspension of treatment in one patient in group A and in one patient in group B.

CONCLUSION

The results showed that Pylera® plus a PPI or ranitidine were equally effective in the population studied. The high cure rates of bismuth triple therapy (without an antisecretory drug) and the lack of susceptibility testing make it impossible to exclude the possibility that the results would have been similar if neither the PPI nor the ranitidine were given.

[Eradication Rates of 10-day Sequential Therapy for Helicobacter pylori: Results of an 8-year Prospective Study Conducted at a Tertiary Korean Hospital]

Background/Aims

The Helicobacter pylori (H. pylori) eradication rate of standard triple therapy is unsatisfactory in Korea, and sequential therapy (SQT) has been suggested to be a practical first-line alternative regimen. The aim of this prospective study was to document changes in annual eradication rates of SQT.

Methods

A total of 983 H. pylori-positive subjects were enrolled from 2010 to 2018 and their data were subjected to intention-to-treat (ITT) and per-protocol (PP) analysis. All subjects received 10-day sequential therapy consisting of 40 mg esomeprazole and 1 g amoxicillin b.i.d for 5 days followed by 40 mg esomeprazole b.i.d, 500 mg clarithromycin b.i.d and 500 mg metronidazole t.i.d for 5 days. The ¹³C-urea breath test, rapid urease test (CLO test^®), and histology were used to confirm eradication. Compliance and side effects were also investigated.

Results

ITT and PP eradication rates of SQT were 69.9% (687 of 983) and 87.1% (657 of 754), respectively. The annual eradication rate of ITT remained consistent over the 8-year study period (p for trend=0.167), whereas PP analysis showed the eradication rate increased (p for trend=0.042). The overall adverse event rate for SQT was 41.7% (410 subjects).

Conclusions

Despite high antibiotic resistance rates in Korea, the eradication rate of SQT did not decrease over the 8-year study period.

Geographically distinct North-East Indian Helicobacter pylori strains are highly sensitive to clarithromycin but are levofloxacin resistant

Purpose

Helicobacter pylori causes various gastro-intestinal diseases. Antibiotic resistance to commonly used antibiotics for the treatment of H. pylori infection is the major cause for treatment failure. The aim of this study is to determine the antimicrobial susceptibility pattern for clarithromycin and levofloxacin and find the evolutionary relationship of the partial sequence of 23S rRNA and gyraseA gene of H. pylori by phylogenetic analysis.

Materials and Methods

A total of 46 H. pylori strains were tested for clarithromycin and levofloxacin susceptibility pattern and phylogenetic tree were reconstructed by PhyML software.

Results

In this study, we observed that only 6.5% of North-East Indian H. pylori strains were resistant for clarithromycin showing mutation at A2143G and T2182C positions of 23S rRNA gene. Resistance for levofloxacin was observed in 89.1% of the H. pylori strains showing mutations at asparagine to lysine at 87 and aspartic acid to glycine/tyrosine/asparagine at 91 positions of gyraseA gene. The phylogenetic tree of the partial sequence of 23S rRNA and gyraseA gene depicts that the North-East Indian strains falls in different cluster when compared to other countries.

Conclusions

Resistance for clarithromycin was less in North-East Indian strains but high for levofloxacin indicating that first-line therapy may be best and effective for eradication of H. pylori in this region. This study is the first report that showed antibiotic susceptibility pattern for clarithromycin and levofloxacin by mutation analysis. By partial sequencing of 23s rRNA and gyraseA gene, we found that North-East Indian strains are geographically distinct.

Molecular diagnosis of Helicobacter pylori antibiotic resistance in the Taif region, Saudi Arabia

Success in eradication of Helicobacter pylori is declining globally because H. pylori has developed resistance against most of the antibiotics proposed for eradication regimens, mainly through point mutations. The present study included 200 patients with dyspepsia attending Taif Hospital. Gastric biopsies were obtained during gastroscopy and subjected to rapid urease testing. Molecular methods were used to confirm diagnoses of H. pylori infection and to identify resistance gene variants of four antibiotics; namely, clarithromycin, metronidazole, fluoroquinolones and tetracycline (23S rRNA, gyrA, rdxA and 16S rRNA respectively). Of all investigated patients, Molecular diagnoses were made in 143 of all investigated patients; thus, the prevalence was .5%. The overall rate of resistance to clarithromycin among the H. pylori-positive patients was high (39.9%) and the rate of resistance significantly greater (48.2%) among the secondary resistance group, secondary resistance being defined as resistance as a result of previous exposure to the relevant antibiotic. The rate of resistance to fluoroquinolones was considered moderate; the difference in rate of resistance between the primary and secondary resistance groups (8.4% and 9.5%, respectively) was not significant Also, there was a low prevalence of both primary and the secondary tetracycline resistance in the study cohort. In contrast, the prevalence of metronidazole resistance was considered high with no significant difference between the two resistance groups. H. pylori showed an increased prevalence of resistance to all four of the commonly used therapeutic agents. Thus, eradication therapy should be based on the regional results of susceptibility testing. Moreover, treatment tailored according to individually determined H. pylori susceptibility may be a reasonable future goal.

Comparison of new and classical point mutations associated with clarithromycin resistance in Helicobacter pylori strains isolated from dyspeptic patients and their effects on phenotypic clarithromycin resistance

PURPOSE

We aimed to investigate the presence of three recently identified point mutations (A2115G, G2141A and A2144T) of the 23 S rRNA gene and compare them with the three most frequently encountered point mutations (A2142G, A2142C and A2143G) in Helicobacter pylori strains in Turkey.

METHODOLOGY

A total of 63 patients (mean 47.08±12.27) were included. The E-test method (for clarithromycin) was used for the clarithromycin antimicrobial susceptibility test of isolated H. pylori strains. Real-time PCR was used to detect the point mutations.

RESULTS

A total of 24 out of 63 H. pylori strains (38.1%) were detected as clarithromycin resistant (>0.5 mg l^-1 ). The new A2115G (n:6, 25%), A2144T (n:7, 29.1%) and G2141A, 8 (n:8, 33.3%) mutations and the classical A2142G (n:8, 33.3%) and A2143G (n:11, 45.8%) point mutations were detected in the 24 clarithromycin-resistant strains. The A2144T point mutation had the highest median MIC value (3 mg l^-1 ) amongst the new mutations, but the classical mutations (A2142G and A2143G) had the highest median MIC values (256 mg l^-1 ) overall. The presence of the A2115G (OR:31.66), A2144T (OR:36.92) or G2141A (OR:28.16) mutations increased the likelihood of clarithromycin resistance in H. pylori strains by 31.66-, 36.92- and 28.16-fold (ORs), respectively, according to the binary logistic regression analysis.

CONCLUSION

We concluded that classical mutations of the 23 S rRNA gene resulted in higher clarithromycin MIC values than new mutations. These new point mutations caused moderate elevations in the MIC values of clarithromycin-resistant H. pylori strains.

Can Aminoglycosides Be Used as a New Treatment for Helicobacter pylori? In vitro Activity of Recently Isolated Helicobacter pylori

BACKGROUND

Smectite can serve as a drug delivery system and gentamicin-intercalated smectite hybrids are expected to supersede the standard therapy for Helicobacter pylori eradication. The aim of this study was to confirm whether the minimum inhibitory concentration (MIC) of aminoglycosides applied as smectite hybrids remained low against recently isolated H. pylori strains.

MATERIALS AND METHODS

A total of 140 strains were collected for a minimum period of 3 years. Antimicrobial susceptibility tests were performed, and the MICs of eight antibiotics (amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, gentamicin, netilmicin, and tobramycin) were determined by using the Epsilometer test and following the European Committee on Antimicrobial Susceptibility Testing recommendations.

RESULTS

The resistance rate of clarithromycin was high, up to 30.7%, although it is a major antimicrobial agent used in standard therapy. The MIC₅₀ and MIC₉₀ of gentamicin (0.25 mg/L and 0.75 mg/L) and netilmicin (0.19 mg/L and 0.75 mg/L) were lower than other alternative therapies for H. pylori eradication. In clarithromycin-resistant strains, the MIC₅₀ was 0.25 mg/L and the MIC₉₀ was 1 mg/L for gentamicin; for netilmicin, the values were 0.25 mg/L and 0.75 mg/L, respectively.

CONCLUSION

Through the use of gentamicin and netilmicin, which have low MICs for H. pylori, aminoglycoside-intercalated smectite hybrids are expected to emerge as a new standard therapy for H. pylori eradication.

Antibiotic resistance in Helicobacter pylori: A mutational analysis from a tertiary care hospital in Kashmir, India

Background

Helicobacter pylori infection is recognised as type 1 carcinogen by the International Agency of Research on Cancer. Previous studies in our hospital have revealed high prevalence of H. pylori in our population with a high recurrence rate after completion of treatment. This prompted us to undertake this study.

Aim

This study aimed to determine common gene mutations leading to resistance to clarithromycin, metronidazole, tetracycline and quinolones in H. pylori in patients attending our hospital.

Settings and Design

This is a cross-sectional hospital-based study. The study was approved by the Institutional Ethics Committee.

Materials and Methods

This study was conducted on 196 adult dyspeptic patients with an indication for upper gastrointestinal endoscopy. Gastric biopsies collected from them were subjected to histopathological examination, rapid urease test (RUT) and culture. Of the 196 patients, 95 met the inclusion criteria. Drug susceptibility testing (DST) by various polymerase chain reaction-based methods was done for 47 RUT-positive biopsies and 13 H. pylori isolates.

Results

Maximum resistance was seen to metronidazole (81.66%) followed by clarithromycin (45%) and quinolones (3.33%). No high-level resistance was seen to tetracycline. In clarithromycin-resistant cases, A2142G mutation was more prevalent than A2143G mutation. Multidrug resistance (resistance to metronidazole and clarithromycin) was seen in 41.66% of patients.

Conclusions

Tetracycline and quinolones could be the antibiotics of choice in the eradication of H. pylori in this region, while recurrence of the infection with H. pylori could be expected among patients receiving either metronidazole or clarithromycin, for eradication therapy. DST should be done on a routine basis utilising both phenotypic and genotypic methods to prevent further emergence of resistance in this region.

[New Helicobacter pylori Eradication Therapies]

While the prevalence of Helicobacter pylori (H. pylori) infection is decreasing in Korea, the incidence of gastric cancer remains high, emphasizing the importance of H. pylori eradication. A new treatment strategy is needed as the eradication rate with standard triple therapy, which is currently the standard first-line regimen for H. pylori infection, has decreased below the optimum level. The major cause of eradication failure is increased antibiotic resistance. Sequential, concurrent, and hybrid therapies that include clarithromycin produce higher eradication rates than conventional standard triple therapy. However, the effectiveness of these treatments is limited in regions where the resistance rate to various antibiotics is high. Bismuth quadruple therapy is another alternative therapy, but again the eradication rate is not sufficiently high. Tailored therapy based on individual characteristics, including antibiotic susceptibility, may be ideal, but there are several limitations for clinical application and further research is needed. New potassium-competitive acid blocker-based therapies could emerge as effective alternatives in the near future. A consensus is needed to establish a strategy for applying new eradication therapies in Korea.

Peptide Nucleic Acid Probe-Based Analysis as a New Detection Method for Clarithromycin Resistance in Helicobacter pylori

Background/Aims

Helicobacter pylori eradication rates are decreasing because of increases in clarithromycin resistance. Thus, finding an easy and accurate method of detecting clarithromycin resistance is important.

Methods

We evaluated 70 H. pylori isolates from Korean patients. Dual-labeled peptide nucleic acid (PNA) probes were designed to detect resistance associated with point mutations in 23S ribosomal ribonucleic acid gene domain V (A2142G, A2143G, and T2182C). Data were analyzed by probe-based fluorescence melting curve analysis based on probe-target dissociation temperatures and compared with Sanger sequencing.

Results

Among 70 H. pylori isolates, 0, 16, and 58 isolates contained A2142G, A2143G, and T2182C mutations, respectively. PNA probe-based analysis exhibited 100.0% positive predictive values for A2142G and A2143G and a 98.3% positive predictive value for T2182C. PNA probe-based analysis results correlated with 98.6% of Sanger sequencing results (κ-value=0.990; standard error, 0.010).

Conclusions

H. pylori clarithromycin resistance can be easily and accurately assessed by dual-labeled PNA probe-based melting curve analysis if probes are used based on the appropriate resistance-related mutations. This method is fast, simple, accurate, and adaptable for clinical samples. It may help clinicians choose a precise eradication regimen.

[The Efficacy of Bismuth-containing Quadruple Therapy after Moxifloxacin-based Sequential Therapy Failure in Helicobacter pylori Eradication]

Background/Aims

Moxifloxacin-based sequential therapy showed an excellent eradication rate as the first line treatment of Helicobacter pylori (H. pylori) infection. However, to the best of our knowledge, there were only a few studies on the treatment of those with failed moxifloxacin-based sequential therapy. Hence, this study was to investigate the efficacy of bismuth-containing quadruple therapy in those with failed moxifloxacin-based sequential or reverse sequential therapy for H. pylori eradication.

Methods

Between January 2013 and March 2016, we retrospectively analyzed patients who failed to eradicate H. pylori using moxifloxacin-based sequential (rabeprazole 20 mg bid and amoxicillin 1 g bid for 5-7 days, followed by rabeprazole 20 mg bid, metronidazole 500 mg bid, and moxifloxacin 400 mg qd for 5-7 days) and 10 days moxifloxacin-based reverse sequential therapy as the first line treatment. Then we investigated the eradication rates of bismuth-containing quadruple therapy as the second line treatment. All subjects had no history of H. pylori eradication before. Eradication rates were described as intention-to-treat (ITT) and per-protocol (PP) analyses. H. pylori status was evaluated by ¹³C-urea breath test 6 weeks after the end of the treatment. Moreover, we examined any side effects that caused discontinuation of therapy.

Results

Twenty-three patients received bismuth-containing quadruple therapy as the second line treatment. The overall eradication rates by ITT and PP analyses were 60.87% (n=14/23) and 73.68% (n=14/19). All the patients showed good compliance, and there were no serious adverse events.

Conclusions

Bismuth-containing quadruple therapy is insufficient as the second line eradication treatment after a failed attempt of moxifloxacin-based sequential or reverse sequential therapy. Large-scale clinical trials should be performed to establish better clinical evidence.

The magnitude of antibiotic resistance to Helicobacter pylori in Africa and identified mutations which confer resistance to antibiotics: systematic review and meta-analysis

Background

Worldwide Helicobacter pylori (H.pylori) treatment is of great challenge due to increased antibiotic resistance. The burden of H. pylori antibiotic resistance in Africa is high with unclear information regarding the real magnitude. This systematic review and meta-analysis was conducted to investigate the magnitude of H.pylori antibiotic resistance in Africa to gain insight of the extent of the problem among H.pylori naïve treatment patients.

Method

The search was performed in the academic databases, Embase, PubMed, Web of Science and Africa Wide Information. ProQuest Dissertation and Theses, Scopus, Ethos, Africa Index Medicus (WHO), BioMed Central Proceedings, BASE, British Library, Open grey, Library of Congress and the New York Academy of Grey Literature Report were additionally searched for grey literature. Published articles from Africa on H.pylori antibiotic resistance between 1986 and June 2017 were systematically reviewed to estimate the H. pylori extent of resistance to macrolides, quinolones, amoxicillin, tetracycline and metronidazole.

Results

In 26 articles a total of 2085 isolates were tested for metronidazole, 1530 for amoxicillin, 1277 for tetracycline, 1752 for clarithromycin and 823 for quinolones.The overall pooled proportion of H.pylori resistance to quinolones, clarithromycin, tetracycline, metronidazole and amoxicillin were: (17.4%, 95%CI 12.8 - 21.9), (29.2%, 95%CI:26.7-31.8), (48.7%, 95%CI: 44.5-52.9), (75.8%, 95% CI: 74.1-.77.4) and (72.6%, 95% CI: 68.6-76.6), respectively. The commonest mutation detected were A2143G (49/97) for clarithromycin, RdxA (41/56) for metronidazole and D87I (16/40) for quinolones.

Conclusion

Prevalence of metronidazole, clarithromycin, and amoxicillin resistance is high in developing world including Africa. This could impair the first line triple therapy of the H.pylori infection. There is a need of conducting surveillance of H.pylori susceptibility pattern in Africa for dual and triple resistance which can be used for the empirical treatment.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3099-4) contains supplementary material, which is available to authorized users.

rdxA, frxA, and efflux pump in metronidazole-resistant Helicobacter pylori: Their relation to clinical outcomes

BACKGROUND AND AIM

rdxA and frxA mutations and enhancement of efflux pump have been suggested as the cause of metronidazole resistance in Helicobacter pylori. This study was performed to investigate the resistance mechanisms related to clinical eradication outcome, and to examine direct involvement of hefA in metronidazole-resistant isolates with intact rdxA and frxA.

METHODS

A total of 53 H. pylori-positive patients who were treated with metronidazole-containing sequential or quadruple therapy from 2011 to 2015 were enrolled. The metronidazole susceptibility of H. pylori isolates was examined by agar dilution test. Mutations in rdxA and frxA, were analyzed with DNA sequencing, and impact of hefA on metronidazole resistance was examined with quantitative real-time reverse transcription polymerase chain reaction, knockout and genetic complementation test for hefA.

RESULTS

Seven mutation types of rdxA and/or frxA were found in H. pylori isolated from non-eradicated subjects. rdxA mutation was associated with eradication failure (P = 0.002), and nonsense mutation in rdxA reduced eradication efficacy (P = 0.009). hefA expression was significantly higher in resistant isolates (P < 0.001), especially in rdxA(-)frxA(-) as compared to rdxA(+)frxA(+) (P = 0.027). Resistant isolates with no mutation in rdxA and frxA became susceptible after hefA knockout. Genetic complementation for hefA recovered metronidazole resistance in all of three hefA knockout mutants.

CONCLUSIONS

These results suggest that rdxA mutations play a critical role in metronidazole resistance as well as the outcomes of eradication therapy. In addition, hefA seems to be directly involved in metronidazole resistance, which explains the resistance in clinical isolates with intact rdxA and frxA.

Eradication of Helicobacter Pylori in Iran: A Review

Helicobacter pylori (H. pylori) infection is one of the most common bacterial infections, affecting almost half of the world’s population. It is associated with peptic ulcer disease, gastric adenocarcinoma, and lymphoma. In Iran, the prevalence of H. pylori infection has been reported to be between 36% and 90% in different geographic regions.

Several studies have assessed the efficacy of different therapeutic options for firstline and second-line H. pylori eradication in Iran; however, the results are conflicting. Therefore, we conducted a review to evaluate different studies in order to select the best options and to provide recommendations for H. pylori eradication in Iran. Accordingly, we searched through PubMed to obtain relevant randomized clinical trials published in English language up to June 2017.

According to our study, among first-line eradication regimens, bismuth-based furazolidone- or clarithromycin-containing quadruple therapies, hybrid regimen, and concomitant therapy seem to be appropriate options. Also, 10- or 14-day clarithromycin-containing triple therapy can be used if local H. pylori resistance to clarithromycin is known to be less than 15%.

For second-line H. pylori eradication, bismuth-based quadruple therapies and 14-day levofloxacin-based triple therapy can be used, provided that antibiotics other than those used in the first-line regimen are used. Third-line H. pylori eradication regimens have not been addressed in Iranian studies. However, most guidelines recommend treatment according to the results of culture and susceptibility testing.

Although we limited our investigation to H. pylori eradication regimens in Iran, the results are transferrable to any region as long as the patterns of antibiotic resistance are the same.

[The Efficacy of Moxifloxacin-containing Triple Therapy after Hybrid Therapy Failure in Helicobacter pylori Eradication]

Background/Aims

Hybrid therapy was successful in eradicating Helicobacter pylori (H. pylori) according to previous reports. However, to the best of our knowledge, there have only been a few studies evaluating the optimal choice after hybrid failure. Hence, we aimed to evaluate the efficacy of moxifloxacin-containing triple therapy after hybrid therapy failure in H. pylori eradication.

Methods

Between January 2013 and March 2016, we retrospectively reviewed patients who underwent failed hybrid therapy, as first line treatment, in eradicating H. pylori (rabeprazole and amoxicillin b.i.d for 14 days, in addition to clarithromycin and metronidazole b.i.d for final 7 days). Then, we investigated the eradication rates of moxifloxacin-containing triple therapy (rabeprazole, amoxicillin b.i.d and moxifloxacin qd) as the second line of treatment. Intention-to-treat (ITT) and per-protocol (PP) analyses were used to determine the eradication rate. We evaluated the status of H. pylori by using ¹³C-urea breath test 6 weeks after the final treatment. Moreover, compliance and adverse effects of each patient were analyzed.

Results

Among those who failed the initial hybrid therapy, 11 patients received moxifloxacin-containing triple therapy. The overall eradication rates, as determined by ITT and PP, were 72.7% (n=8/11) and 80% (n=8/10), respectively. The compliance rate was 100%, and there were no serious adverse effects.

Conclusions

Moxifloxacin-containing triple therapy can be used as a second line therapy in case of hybrid therapy failure. A large scale study is necessary to confirm the findings of this study and establish clinical evidence.

Primary Helicobacter pylori resistance in elderly patients over 20 years: A Bulgarian study

We evaluated the antibiotic susceptibility of 233 Helicobacter pylori strains isolated in the period 2011-2016, involving 62 strains from elderly patients aged 66-93years and 171 strains from younger adults. To assess resistance evolution, primary resistance rates in 92 strains from as many patients aged ≥60years in 1996-2003 were compared with those in 85 strains from infected patients in the same age group in 2011-2016. In the patients aged >65years evaluated during the last 6 years, amoxicillin resistance according to EUCAST and prior breakpoints was 1.6 and 0%, respectively. Resistance rates were the same by both breakpoint systems to metronidazole (35.5%), clarithromycin (22.6%), tetracycline (1.6%) and levofloxacin (32.3%). In 2011-2016, there were no significant differences between resistance rates in the subjects aged >65years and the younger adults. Notably, during the last 6 years, double/triple resistance was found in 21.0% of the subjects aged >65years. Moreover, the prevalence of quinolone primary resistance (30.0%) was significantly (3.4-fold) higher than that (8.9%) observed in 1996-2003. Briefly, the presence of both combined resistance and a strikingly high primary levofloxacin resistance in the elderly implies a cautious antibiotic choice for H. pylori eradication. In vitro susceptibility testing of the strains is highly important in this age group. The results can be linked to more frequent comorbidities and co-infection treatment in older compared with younger patients and, additionally, to the national antibiotic consumption. The high prevalence of quinolone resistance in the elderly patients is an alarming finding.

Clarithromycin-Based Triple Therapy is Still Useful as an Initial Treatment for Helicobacter pylori Infection in the Dominican Republic

AbstractHelicobacter pylori antibiotic susceptibility in the Dominican Republic has not been monitored. We assessed H. pylori antibiotic susceptibility in the Dominican Republic, and analyzed H. pylori mutations associated with antibiotic resistance. We recruited 158 dyspeptic patients in Santo Domingo and used agar dilution to test susceptibility to five antibiotics. Polymerase chain reaction-based sequencing was used to assess gyrA, gyrB, rdxA, frxA, and 23S rRNA mutations; next-generation sequencing was used to identify other metronidazole resistance-associated genes. Among 64 H. pylori strains isolated, we identified two (3.1%), one (1.6%), and no strains with clarithromycin, amoxicillin, and tetracycline resistance, respectively. Moreover, high frequency of metronidazole resistance (53/64, 82.8%) was observed, whereas levofloxacin resistance is emerging (23/64, 35.9%). We identified many rdxA and frxA mutations in metronidazole-resistant strains, but no synergistic effect was apparent. We revealed novel mutations in dppA, dppB, fdxA, and fdxB, irrespective of rdxA and frxA mutations. Novel mutations at Ser-14 of trx1 and Arg-221 of dapF were associated with different levels of metronidazole resistance. Most levofloxacin-resistant strains had a substitution at Asn-87 of gyrA, including the strain with the highest levofloxacin resistance, whereas only three substitutions were found at Ser-479 of gyrB with no synergistic effect. Besides the 23S rRNA A2142G mutation, we observed another mutation at T1958G in both clarithromycin-resistant strains. We confirmed high metronidazole and levofloxacin resistance associated with genetic mutations in the Dominican Republic. However, prevalence of clarithromycin resistance was low, suggesting that standard clarithromycin-based triple therapy remains useful as initial treatment of H. pylori infection.

Optimal First-Line Treatment for Helicobacter pylori Infection: Recent Strategies

A new treatment strategy is needed, as the efficacy of triple therapy containing clarithromycin—the current standard treatment for Helicobacter pylori infection—is declining. Increasing antibiotic resistance of H. pylori is the most significant factor contributing to eradication failure. Thus, selecting the most appropriate regimen depending on resistance is optimal, but identifying resistance to specific antibiotics is clinically challenging. In a region suspected to have high clarithromycin resistance, bismuth quadruple therapy and so-called nonbismuth quadruple therapies (sequential, concomitant, and sequential-concomitant hybrid) are some first-line regimen options. However, more research is needed regarding appropriate second-line treatments after first-line treatment failure. Tailored therapy, which is based on antibiotic sensitivity testing, would be optimal but has several limitations for clinical use, and an alternative technique is required. A novel potassium-competitive acid blocker-based eradication regimen could be a valuable eradication option in the near future.

Rifabutin Containing Triple Therapy and Rifabutin with Bismuth Containing Quadruple Therapy for Third-Line Treatment of Helicobacter pylori Infection: Two Pilot Studies

AIM

To evaluate the therapeutic gain of the addition of bismuth to a rifabutin containing triple therapy with amoxicillin and pantoprazole at standard dosages for the treatment of third-line Helicobacter pylori infection after a preliminary susceptibility test.

METHODS

Two separate groups of patients in two pilot studies which were carried out simultaneously. One group was treated with rifabutin 150 mg b.i.d., pantoprazole 20 mg b.i.d., and amoxicillin 1 g b.i.d. for 10 days and the other group with rifabutin 150 mg b.i.d., pantoprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and bismuth subcitrate 240 mg b.i.d. for 10 days. All patients underwent to culture and susceptibility testing prior to their inclusion in the study. A successful outcome was confirmed with an Urea Breath test performed 8 weeks after the end of treatment. A blood cell count was performed for all patients at the start and after 5 days of treatment since rifabutin has been shown to inhibit the growth of leucocytes.

RESULTS

Twenty-nine patients were recruited in the pantoprazole, amoxicillin, rifabutin group and 30 in the pantoprazole, amoxicillin, rifabutin, and bismuth subcitrate group. All patients had a positive H. pylori culture and the susceptibility test used showed H. pylori sensitivity to rifabutin and amoxicillin. H. pylori eradication during follow-up was 18/27 (66.7%, 95% CI: 47.7-85.7%) in the pantoprazole, amoxicillin, rifabutin group and 28/29 (96.6%, 95% CI: 89.5-100.0%) in the pantoprazole, amoxicillin, rifabutin, and bismuth subcitrate group. Both treatments were well-tolerated with no reported side effects. Blood cell count remained normal in all patients.

CONCLUSION

The addition of bismuth subcitrate to a triple therapy that includes proton pump inhibitors, amoxicillin, and rifabutin in patients who are treated for the third time for H. pylori infection resulted in a 30% therapeutic gain.

Comparison of sequential therapy and amoxicillin/tetracycline containing bismuth quadruple therapy for the first-line eradication of Helicobacter pylori: a prospective, multi-center, randomized clinical trial

BACKGROUND

The <80 % Helicobacter pylori eradication rate with sequential therapy is unsatisfactory. Modified bismuth quadruple therapy, replacing metronidazole with amoxicillin, could be promising because H. pylori resistance to tetracycline or to amoxicillin is relatively low. A 14-day modified bismuth quadruple protocol as first-line H. pylori treatment was compared with 10-day sequential therapy.

METHODS

In total, 390 H. pylori-infected subjects participated in the randomized clinical trial: 10-day sequential therapy (40 mg pantoprazole plus 1 g amoxicillin twice a day for 5 days, then 40 mg pantoprazole and 500 mg clarithromycin twice a day and 500 mg metronidazole three times a day for 5 days) or 14-day modified bismuth quadruple therapy (40 mg pantoprazole, 600 mg bismuth subcitrate, 1 g tetracycline, and 1 g amoxicillin, twice a day). (13)C-urea breath test, rapid urease testing, or histology was performed to check for eradication.

RESULTS

Intention-to-treat (ITT) eradication rates of 10-day sequential and 14-day quadruple therapy were 74.6 % and 68.7 %, respectively, and the per-protocol (PP) rates were 84.2 and 76.5 %, respectively. The eradication rate was higher in the sequential therapy group, but neither the ITT nor the PP analyses had a significant difference (P = 0.240 and P = 0.099, respectively). However, the adverse events were significantly lower in the modified bismuth quadruple therapy group than the sequential therapy group (36.9 vs. 47.7 %, P = 0.040).

CONCLUSIONS

Ten-day sequential therapy appears to be more effective despite frequent adverse events. However, both 10-day SQT and 14-day PBAT did not reach the excellent eradication rates that exceed 90 %. Additional trials are needed to identify a more satisfactory first-line eradication therapy.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT02159976 ); Registration date: 2014-06-03, CRIS ( KCT0001176 ); Registration date: 2014-07-23.

Low prevalence of clarithromycin-resistant Helicobacter pylori isolates with A2143G point mutation in the 23S rRNA gene in North India

Resistance of Helicobacter pylori to clarithromycin is associated with a single base substitution in the 23S rRNA gene. In this study, clarithromycin-resistant H. pylori isolates were analysed for the presence of 23S rRNA gene mutations. H. pylori were isolated from 68 patients suffering from various gastroduodenal diseases in North India. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method, and point mutations in clarithromycin-resistant strains were identified by PCR-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing. Clarithromycin resistance was observed in 11.8% (8/68) of the H. pylori isolates in North India. The A2143G point mutation in the 23S rRNA gene was found in 87.5% (7/8) of the clarithromycin-resistant strains, and the A2142G mutation in association with the T2182C mutation was found in 12.5% (1/8). In conclusion, the continued high prevalence of clarithromycin-sensitive H. pylori strains (88.2%) observed in this study allows the use of the triple-therapy regimen for the treatment of H. pylori infection in this region. Surveillance studies need to be conducted at regular intervals for clarithromycin resistance in the population. To our knowledge, this is the first study in India to report that point mutations at position A2143G and at A2142G in association with T2182C are associated with clarithromycin resistance, confirming reports from other parts of the world.

Effects of Clarithromycin-Containing Quadruple Therapy on Helicobacter Pylori Eradication after Nitroimidazole-Containing Quadruple Therapy Failure

BACKGROUND

Several large clinical trials and meta-analyses have shown about 20% failure to eradicate Helicobacter pylori (H.pylori), necessitating investigations for second-line treatments. The aim of this study was to evaluate the effects of clarithromycin-containing quadruple regimen after nitroimidazole-containing quadruple therapy failure.

METHODS

Thirty two patients who had failed 10-day H.pylori treatment with omeprazole, amoxicillin, bismuth subcitrate, and metronidazole (OABM) regimen and 31 patients who had failed 10-day treatment with omeprazole, amoxicillin, bismuth subcitrate, and furazolidone (OAMF) regimen entered the study. They all received omeprazole (20 mg), amoxicillin (1 gr), bismuth subcitrate (240 mg) and clarithromycin (500 mg) twice a day for 10 days. Eight weeks after treatment, H. pylori eradication was assessed by ¹⁴C-urea breath test.

RESULTS

Totally 61 patients completed the study. According to intention to treat (ITT) analysis, eradication rates by second-line OABC regimen were 84.37% (95% CI= 71.7–96.9%) in OABM group and 77.41% (95% CI= 62.71–92.11%) in OABF group (p=0.756). Per-protocol (pp) eradication rates were 87.09% (95% CI= 75.2–98.8%) and 82.75% (95% CI= 79.4–96%), respectively (p=0.638). Also the cumulative eradication rates by OABC regimen were 80.9% (95% CI= 71.2–90.6%) and 85% (95% CI= 75.9–94%) according to ITT and PP analyses, respectively. Severe side effects were reported in 3.1% of the patients.

CONCLUSION

Regarding ideal eradication rate (>80%) and very low adverse effects, it seems that clarithromycin-containing quadruple therapy can be an encouraging regimen after nitroimidazole-containing regimen failure.

In vitro antimicrobial susceptibility of Helicobacter pylori to nine antibiotics currently used in Central Italy

OBJECTIVE

Helicobacter pylori expresses an increased resistance in respect to antimicrobials currently used in therapy. The aim of this study was to evaluate the antimicrobial profiles of H. pylori isolates to nine conventional antibiotics used in a Central Region (Abruzzo) of Italy.

MATERIALS AND METHODS

Biopsies were taken from antrum and fundus of 112 adult and 3 children with Urea Breath Test positive with dyspeptic symptoms and analyzed for H. pylori culture and antibacterial activity. Antimicrobial susceptibility tests were performed for clarithromycin, metronidazole, levofloxacin, moxifloxacin, ciprofloxacin, tetracycline, amoxicillin, ampicillin, and rifabutin by a modified agar dilution susceptibility test.

RESULTS

Bacterial culture was successful in 100 out of 115 patients. Helicobacter pylori strains were isolated from 98 antrum and 83 fundus samples. The rate of recovery of H. pylori strains was 90.50% (181/200). The percentages of resistance were as follows: clarithromycin 72.44% antrum, 72.28% fundus; metronidazole 34.69% antrum, 42.16% fundus; levofloxacin 42.85% antrum, 53.01% fundus; moxifloxacin 37.35% antrum, 46.57% fundus; ciprofloxacin 39.47% antrum, 44.28% fundus; tetracycline 2.63% antrum, 2.85% fundus; amoxicillin 1.02% antrum, 1.20% fundus; ampicillin 0% antrum and fundus and rifabutin 0% antrum, 1.20% fundus. A total of 35 subjects harbored multi-resistant strains.

CONCLUSIONS

This study underlines the high rate of resistance to clarithromycin, metronidazole and quinolones, which may reflect an overuse of them. Culture and susceptibility test, should be performed to prevent the emergence of multi-resistance and to assess an efficacious regimen.

Extremely High Prevalence of Metronidazole-Resistant Helicobacter pylori Strains in Mountain People (Karen and Hmong) in Thailand

This study aimed to survey the prevalence, patterns of antibiotic resistance, and clinical factors associated with antibiotic resistance in Helicobacter pylori among the Karen and Hmong mountain people of Thailand. We recruited dyspeptic patients in the Maesod district, Tak Province, Thailand. All subjects underwent upper gastrointestinal endoscopy, and three antral gastric biopsies were obtained for rapid urease tests and culture. An epsilometer was used to determine the minimum inhibitory concentrations of amoxicillin (AMX), clarithromycin (CLR), metronidazole (MNZ), levofloxacin (LVX), ciprofloxacin (CIP), and tetracycline (TET). A total of 291 subjects were enrolled; 149 (51.2%) were infected with H. pylori. Helicobacter pylori infection was present in 47.1% of Thai, 51.7% of Karen, and 58.7% of Hmong subjects. Antibiotic resistance was present in 75.8% including AMX (0.8%), TET (0%), CLR (5.6%), MNZ (71.8%), CIP (19.4%), LVX (19.4%), and multidrug resistance in 21.8%. Karen subjects had the highest prevalence of MNZ resistance (84.6%), and Hmong subjects had the highest prevalence of fluoroquinolone (27.3%) and multidrug (34.1%) resistance. MNZ plus fluoroquinolone (14.5%) was the most common multidrug resistance. There was no association between clinical factors and antibiotic resistance. MNZ resistance was prevalent, whereas fluoroquinolone- and multidrug-resistant H. pylori infections are important problems in mountain people of Thailand.

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.

Serologic Evidence for Fecal-Oral Transmission of Helicobacter pylori

Helicobacter pylori infection is among the most prevalent infections in the world and a key cause of gastric diseases; however, its route of transmission remains unclear. This study aimed to assess the potential for fecal-oral transmission of H. pylori by leveraging its association with a disease with known etiology. Utilizing serology data from the National Health and Nutrition Examination Survey (NHANES 1999; N = 6,347), the association between H. pylori and hepatitis A virus (HAV), a sensitive indicator for fecal-oral exposure, was assessed. Survey-weighted kappa and multiple logistic regression were used to quantify the association between H. pylori and HAV after controlling for age, sex, race, poverty, birthplace, crowding, smoking, and alcohol use. Concordant serological results were found among 69.8% of participants (survey-weighted κ = 0.30, 95% confidence interval [CI] = 0.26, 0.35). The adjusted odds of H. pylori seropositivity were over two times higher after adjusting for confounders (odds ratio = 2.27, 95% CI = 1.79, 2.87). Results from this study suggest H. pylori and HAV infections are strongly associated. Since HAV is primarily transmitted through the fecal-oral route, fecal-oral transmission may be an important pathway for H. pylori spread.

Helicobacter pylori in gastric carcinogenesis

Gastric cancer still is a major concern as the third most common cancer worldwide, despite declining rates of incidence in many Western countries. Helicobacter pylori (H. pylori) is the major cause of gastric carcinogenesis, and its infection insults gastric mucosa leading to the occurrence of atrophic gastritis which progress to intestinal metaplasia, dysplasia, early gastric cancer, and advanced gastric cancer consequently. This review focuses on multiple factors including microbial virulence factors, host genetic factors, and environmental factors, which can heighten the chance of occurrence of gastric adenocarcinoma due to H. pylori infection. Bacterial virulence factors are key components in controlling the immune response associated with the induction of carcinogenesis, and cagA and vacA are the most well-known pathogenic factors. Host genetic polymorphisms contribute to regulating the inflammatory response to H. pylori and will become increasingly important with advancing techniques. Environmental factors such as high salt and smoking may also play a role in gastric carcinogenesis. It is important to understand the virulence factors, host genetic factors, and environmental factors interacting in the multistep process of gastric carcinogenesis. To conclude, prevention via H. pylori eradication and controlling environmental factors such as diet, smoking, and alcohol is an important strategy to avoid H. pylori-associated gastric carcinogenesis.

A Triple and Quadruple Therapy with Doxycycline and Bismuth for First-Line Treatment of Helicobacter pylori Infection: A Pilot Study

BACKGROUND

Tetracycline-containing triple therapy has been suggested as an alternative first-line therapy for H. pylori infection.

AIM

To evaluate the effect of two dosages of doxycycline (DOX) associated with amoxicillin and esomeprazole with and without bismuth subcitrate as first-line treatment of H. pylori infection.

METHODS

Helicobacter pylori-positive patients underwent a 10-day therapy randomized into four groups: Group A received esomeprazole, amoxicillin, and DOX-100 mg b.i.d. (EAD-100), Group B a quadruple therapy with esomeprazole, amoxicillin, DOX-100 mg b.i.d. and bismuth subcitrate (EADB-100), Group C a triple therapy with esomeprazole, amoxicillin, and DOX-200 mg b.i.d. (EAD-200) and Group D a quadruple therapy with esomeprazole, amoxicillin, DOX-200 mg b.i.d., and bismuth subcitrate (EADB-200). Success was accessed by (13)C urea breath test 2 months after the end of treatment. The number of patients to be recruited for each group had to be at least 50 subjects. Treatment success of 80% or less was considered unacceptable. Stopping rules therefore were anytime six failures had occurred.

RESULTS

In the EAD-100 group and in EAD-200 group, the recruitment was stopped at the 14th and 15th patient, respectively. Fifty-two patients entered in the EADB-100 group and 51 in the EADB-200 group. Intention to treat eradication was in EADB-100 group 46/52 (88.5%, 95% CI 76.6-95.6); in the EADB-200 group 47/51 (92.1%, 95% CI: 81.1-97.8) (n.s.). Side effects were absent.

CONCLUSION

The adjunction of bismuth subcitrate to a triple therapy that includes esomeprazole, amoxicillin, and DOX in patients who are treated for the first time for the H. pylori infection potentiates the therapeutic effect. This regimen, however, deserves to be optimized in terms of duration and dose of DOX.