Development and evaluation of a simple PCR assay and nested PCR for rapid detection of clarithromycin-resistant Helicobacter pylori from culture and directly from the biopsy samples in India

BACKGROUND

Eradication of Helicobacter pylori provides the most effective treatment for gastroduodenal diseases caused by H. pylori infection. Clarithromycin, a member of the macrolide family, still remains the most important antibiotic used in H. pylori eradication treatment. But the increasing prevalence of clarithromycin resistant H. pylori strains due to point mutations in the V region of the 23S rRNA, poses a great threat in treating the ailing patients. So, we aimed for PCR-mediated rapid detection of the point mutation at 2143 position of 23S rRNA gene in H. pylori that is relevant to clarithromycin resistance from culture and simultaneously from biopsy specimens to avoid the empirical treatment.

RESULTS

Newly developed PCR assay using DNA of pure culture detected point mutation in 23S rRNA gene in 21 (8.04%) of 261 clinical strains tested. The agar dilution method showed that all these 21 strains were resistant to clarithromycin indicating the perfect match of the PCR based results. Additionally, the sequencing study also identified the A to G mutation at 2143 position in 23S rRNA gene of the resistant strains only. Consequently, the newly developed Nested-ASP-PCR dealing directly with 50 biopsy specimens demonstrated 100% sensitivity and specificity with the findings of agar dilution method taken as Gold standard. Bioinformatics based analysis such as accessibility analysis and dot plot clearly stated that the base pairing probability has increased due to mutation. Computational studies revealed that the point mutation confers more stability in secondary structure due to conversion of loop to stem. Furthermore, interaction studies showed binding affinity of the CLR to the mutant type is weaker than that to the wild type.

CONCLUSION

This assay outlines a rapid, sensitive and simple approach to identify point mutation that confers clarithromycin resistance as well as clarithromycin sensitive strains, providing rapid initiation of effective antibiotic treatment. Additionally, it is simple to adopt for hospital based diagnostic laboratories to evaluate the degree of regional clarithromycin resistance from biopsy specimens itself. Furthermore, in silico studies provide evidence or a signal that the prevalence of clarithromycin resistance may rise in the near future as a result of this point mutation.

The Emergence of Multidrug-Resistant Helicobacter pylori in Southeast Asia: A Systematic Review on the Trends and Intervention Strategies Using Antimicrobial Peptides

The emergence of multidrug-resistant H. pylori poses a public healthcare threat, particularly in low- and middle-income countries. Recently, the World Health Organization has classified clarithromycin-resistant H. pylori as high priority in the research and discovery of novel antibiotics. This study was aimed to systematically review the prevalence of primary antibiotic resistance in H. pylori in Southeast Asian countries (SEAC) and to review current studies of antimicrobial peptides against H. pylori. We systematically searched through electronic databases of studies conducted on antimicrobial resistance of H. pylori in SEA countries. Furthermore, we searched articles that conducted studies on antimicrobial peptides, naturally occurring host’s defense molecules, against H. pylori. After a series of screening processes, 15 studies were included in our systematic review. Our analysis revealed that primary resistance of H. pylori to metronidazole, clarithromycin, and levofloxacin were high in SEAC, although the primary resistance to amoxicillin and tetracycline remains low. Multidrug-resistant H. pylori are emerging in SE Asian countries. The antimicrobial peptides show promising antibacterial and antibiofilm activity against drug-resistant H. pylori. The research and discovery of antimicrobial peptides against H. pylori in SEAC will help in limiting the spread of antimicrobial resistance of H. pylori.

Primary and secondary clarithromycin resistance in Helicobacter pylori and mathematical modeling of the role of macrolides

Clarithromycin is a macrolide antibiotic widely used for eradication of Helicobacter pylori infection, and thus resistance to this antibiotic is a major cause of treatment failure. Here, we present the results of a retrospective observational study of clarithromycin resistance (Cla-res) in 4744 H. pylori-infected patients from Central Hungary. We use immunohistochemistry and fluorescence in situ hybridization on fixed gastric tissue samples to determine H. pylori infection and to infer Cla-res status, respectively. We correlate this information with macrolide dispensing data for the same patients (available through a prescription database) and develop a mathematical model of the population dynamics of Cla-res H. pylori infections. Cla-res is found in 5.5% of macrolide-naive patients (primary Cla-res), with no significant sex difference. The model predicts that this primary Cla-res originates from transmission of resistant bacteria in 98.7% of cases, and derives from spontaneous mutations in the other 1.3%. We find an age-dependent preponderance of female patients among secondary (macrolide-exposed) clarithromycin-resistant infections, predominantly associated with prior use of macrolides for non-eradication purposes. Our results shed light into the sources of primary resistant cases, and indicate that the growth rate of Cla-res prevalence would likely decrease if macrolides were no longer used for purposes other than H. pylori eradication.

Prevalence of Antibiotic Resistance in Helicobacter pylori: A Systematic Review and Meta-analysis in World Health Organization Regions

BACKGROUND & AIMS

In 2017, the World Health Organization (WHO) designated clarithromycin-resistant Helicobacter pylori a high priority for antibiotic research and development. However, there are no clear data on the global distribution of resistance or its clinical effects. We performed a systematic review and meta-analysis to assess the distribution of H pylori resistance to commonly used antibiotics and to measure the association between antibiotic resistance and treatment failure.

METHODS

We searched publication databases for studies that assessed rates of H pylori resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, or tetracycline. Pooled estimates of primary and secondary resistance and 95% confidence intervals (CIs) were grouped by WHO region. The association between antibiotic resistance and treatment failure was measured by extracting data on treatment efficacy in patients with resistant and susceptible isolates and pooling odds ratios with 95% CIs.

RESULTS

We identified 178 studies, comprising 66,142 isolates from 65 countries. Primary and secondary resistance rates to clarithromycin, metronidazole, and levofloxacin were ≥15% in all WHO regions, except primary clarithromycin resistance in the Americas (10%; 95% CI, 4%-16%) and South-East Asia region (10%; 95% CI, 5%-16%) and primary levofloxacin resistance in the European region (11%; 95% CI, 9%-13%). There was considerable heterogeneity (I2 > 75%) among all analyses-this might have resulted from the grouping of resistance rates by country. Increasing antibiotic resistance was observed in most WHO regions. Resistance to clarithromycin was significantly associated with failure of clarithromycin-containing regimens (odds ratio, 6.97; 95% CI, 5.23-9.28; P < .001).

CONCLUSIONS

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

Ten-day high-dose proton pump inhibitor triple therapy versus sequential therapy for Helicobacter pylori eradication

BACKGROUND AND AIM

Eradication rates of Helicobacter pylori following standard triple therapy are declining worldwide, but high-dose proton pump inhibitor-based triple therapy (HD-PPI-TT) and sequential therapy (ST) have demonstrated higher cure rates. We aimed to compare the efficacy and tolerability of HD-PPI-TT and ST in H. pylori-associated functional dyspepsia (FD).

METHODS

One hundred and twenty H. pylori-associated functional dyspepsia patients were randomized to receive 10-day HD-PPI-TT (60 mg lansoprazole/500 mg clarithromycin/1 g amoxicillin, each administered twice daily for 10 days) or 10-day ST (30 mg lansoprazole/1 g amoxicillin, each administered twice daily for 5 days followed by 30 mg lansoprazole/500 mg clarithromycin/400 mg metronidazole, each administered twice daily for 5 days). H. pylori status was determined in post-treatment week 4 by ¹⁴ C-urea breath test. Eradication and antibiotic resistance rates, dyspeptic symptoms, drug compliance, and adverse effects were compared.

RESULTS

Intention-to-treat eradication rates were similar in the ST and HD-PPI-TT groups (85% vs. 80%; P = 0.47). However, the eradication rate was significantly higher following ST compared with HD-PPI-TT in per protocol analysis (94.4% vs. 81.4%; P = 0.035). ST achieved higher cure rates than HD-PPI-TT in clarithromycin-resistant H. pylori strains (100% vs. 33.3%; P = 0.02). Treatment compliance was similar in the HD-PPI-TT and ST groups, although nausea and dizziness were more common in the ST group.

CONCLUSIONS

Sequential therapy achieved better H. pylori eradication than HD-PPI-TT in patients with FD. However, the eradication rate for ST fell from 94.4% in per protocol to 85% in intention-to-treat analysis. Adverse effects might result in poorer compliance and compromise actual ST efficacy (ClinicalTrials.gov: NCT01888237).

Clinical Outcomes of Standard Triple Therapy Plus Probiotics or Concomitant Therapy for Helicobacter pylori Infection

Background/Aims

The efficacy of standard triple therapy (STT) in treating Helicobacter pylori infection has decreased. Many investigators have attempted to increase the eradication rate. We investigated the outcomes of concomitant therapy (CT) and STT combined with probiotics (STP) as a first-line treatment for H. pylori infection.

Methods

We reviewed the medical records of 361 patients who received either STP (n=286) or CT (n=75). The STP group received STT combined with a probiotic preparation for 1 week. The CT group received STT and metronidazole for 1 week.

Results

The intention-to-treat and per-protocol eradication rates were 83.6% (95% confidence interval [CI], 79.0 to 87.7) and 87.1% (95% CI, 81.2 to 89.7) in the STP group and 86.7% (95% CI, 78.7 to 93.3) and 91.4% (95% CI, 83.6 to 97.1) in the CT group (p=0.512 and p=0.324), respectively. The frequency of adverse effects was higher in the CT group (28.2%) than in the STP group (12.8%) (p=0.002).

Conclusions

STP and CT are encouragingly efficacious as first-line treatments for H. pylori infection. Therefore, adding probiotics to STT may be a feasible option to avoid side effects.

Comparison between different first-line therapy protocols in eradicating Helicobacter pylori in a region with high clarithromycin resistance

Introduction

Helicobacter pylori infection is encountered in more than 50% of the world population. A high rate of clarithromycin resistance is observed among Helicobacter pylori strains in some regions because clarithromycin is a drug commonly used for the treatment of other infections.

Aim

To identify an efficient eradication protocol for patients infected with H. pylori and to suggest an alternative first-line therapy particularly in countries with high clarithromycin resistance.

Material and methods

Patients (18-75 years old) having dyspeptic complaints in a 1-year period and diagnosed with H. pylori infection by gastric biopsy were included and randomised to three groups, each receiving different sequential eradication therapy (LAM-B: lansoprazole, amoxicillin, metronidazole, bismuth: LAM-T: lansoprazole, amoxicillin, metronidazole, tetracycline; LAM-BT: lansoprazole, amoxicillin, metronidazole, bismuth, tetracycline). Eradication was evaluated via urea breath test.

Results

This study included 166 patients (mean age: 40 ±12 years; female, 68.7%) with H. pylori infection. Among them, 50 (30.1%) were in the LAM-B group, 59 (35.5%) were in the LAM-T group, and 57 (34.3%) were in the LAM-BT group. The non-steroidal anti-inflammatory drug use was the lowest in the LAM-BT group. Eradication rates were over 80% and similar in each group, with the highest rate in the LAM-BT group (93%). Adverse event rate was the highest in the LAM-T group. Helicobacter pylori eradication was achieved in 143 (86.1%) patients.

Conclusions

The combination regimens without clarithromycin achieved an eradication rate over 80% in all groups. Knowing and monitoring the regional antibiotic resistance rates is important for successful treatment of H. pylori infections.