Phenotype and Molecular Detection of Clarithromycin and Levofloxacin Resistance in Helicobacter pylori Clinical Isolates in Beijing

Role of MIC levels and 23S rRNA mutation sites to clarithromycin in 14-day clarithromycin bismuth quadruple therapy for Helicobacter pylori eradication: A prospective trial in Beijing

Background

Rising clarithromycin resistance undermines Helicobacter pylori (H. pylori) treatment efficacy. We aimed to determine clarithromycin's minimum inhibitory concentration (MIC) levels and identify specific mutation sites in the 23S ribosomal subunit (23S rRNA) that predict treatment outcomes in a 14-day regimen of clarithromycin bismuth quadruple therapy (amoxicillin 1g, clarithromycin 500 mg, rabeprazole 10 mg, and colloidal bismuth pectin 200 mg).

Materials and methods

We included adult H. pylori patients who hadn't previously undergone clarithromycin-based treatment, either as initial or rescue therapy. Exclusions were made for penicillin allergy, recent use of related medications, severe illnesses, or inability to cooperate. Patients underwent a 14-day clarithromycin bismuth quadruple therapy. Gastric mucosa specimens were obtained during endoscopy before eradication. MIC against amoxicillin and clarithromycin was determined using the E-test method. The receiver operating characteristic (ROC) curve helped to find the optimal clarithromycin resistance MIC breakpoint. Genetic sequences of H. pylori 23S rRNA were identified through Sanger Sequencing. (ChiCTR2200061476).

Results

Out of 196 patients recruited, 92 met the inclusion criteria for the per-protocol (PP) population. The overall intention-to-treat (ITT) eradication rate was 80.00 % (84/105), while the modified intention-to-treat (MITT) and PP eradication rates were 90.32 % (84/93) and 91.30 % (84/92) respectively. No amoxicillin resistance was observed, but clarithromycin resistance rates were 36.19 % (38/105), 35.48 % (33/93), and 34.78 % (33/92) in the ITT, MITT, and PP populations respectively. Compared with the traditional clarithromycin resistance breakpoint of 0.25 μg/mL, a MIC threshold of 12 μg/mL predicted better eradication. Among 173 mutations on 152 sites in the 23S rRNA gene, only the 2143A > G mutation could predict eradication outcomes (p < 0.000).

Conclusions

Interpretation of elevated MIC values is crucial in susceptibility testing, rather than a binary "susceptible" or "resistant" classification. The 2143A > G mutation has limited specificity in predicting eradication outcomes, necessitating further investigation into additional mutation sites associated with clarithromycin resistance.

Current status of Helicobacter pylori resistance to clarithromycin and levofloxacin in Vietnam: Results from molecular analysis of gastric biopsy specimens

OBJECTIVES

The management of Helicobacter pylori in Vietnam is becoming progressively more difficult due to increasing antibiotic resistance, particularly to clarithromycin (CLR) and levofloxaxin (LVX). In Vietnam, the selection of an H. pylori eradication regimen is predominantly based on empirical evidence. However, molecular analysis aimed at identifying H. pylori antibiotic-resistant genotypes is a promising method in antibiotic susceptibility testing. In this study, we aimed to determine the rates of genotypic H. pylori resistance to CLR and LVX by using DNA strip technology in Vietnam.

METHODS

We performed DNA-strip technology-based testing on 112 patients with H. pylori-positive gastroduodenal diseases to detect 23S rRNA and gyrA mutations.

RESULTS

Helicobacter pylori genotypic resistance to CLR and LVX was evident in 81.3% and 53.6% of the patients, respectively, and dual resistance was observed in 48.2%. The 23S rRNA A2142G and A2143G mutations accounted for 1.8% and 79.5% of cases, respectively. The gyrA N87K, D91N, D91G, and D91Y mutations were present in 37.5%, 11.6%, 5.4%, and 5.4% of patients, respectively. All four gyrA mutations were observed in both the naïve and failure patients. We further found an association between the 23S rRNA A2143G mutation and a history of CLR use as well as between the gyrA N87K mutation and a history of LVX use.

CONCLUSIONS

We found a very high prevalence of H. pylori resistance to CLR and LVX and dual resistance to these antibiotics in Vietnam. The application of molecular assays is feasible and may improve the management of H. pylori infection in Vietnam.

Helicobacter pylori antibiotic resistance in different regions of China: A systematic review and meta-analysis

BACKGROUND

Increasing drug resistance of Helicobacter pylori (H. pylori) in China has become one of the major obstacles to the efficacy of empirical eradication therapy. Resistance profiles vary from region to region, which poses an additional challenge to the expansion of empirical eradication therapy.

AIM

To evaluate H. pylori antibiotic resistance in various regions of China systematically.

METHODS

A thorough computerized search of various databases, including PubMed, EMBASE, Web of Science, Sinomed, CNKI, Wanfang Data, and VIP, was conducted to identify cross-sectional studies on H. pylori resistance in various regions of China. Two researchers independently screened the literature, extracted the data, and evaluated the quality of the literature. R 4.3.1 software was used for Meta-analysis of the resistance rate to each antibiotic and their combinations.

RESULTS

A total of 46 eligible articles were included. Clarithromycin (CLA), levofloxacin (LEV), amoxicillin (AMX), tetracycline (TET), metronidazole (MNZ), and furazolidone (FZD) resistance rates in China were 27.72% (95% confidence interval [CI]: 23.80%-31.82%), 31.23% (95%CI: 26.62%-36.02%), 3.97% (95%CI: 1.96%-6.65%), 4.01% (95%CI: 1.36%-7.98%), 75.30% (95%CI: 70.31%-79.97%), and 0.64% (95%CI: 0.13%-1.53%), respectively. The rate of AMX resistance varied significantly among different regions of China, being the highest in South China (7.15%, 95%CI: 6.16%-76.10%) and the lowest in North China (1.86%, 95%CI: 0.67%-3.64%). CLA resistance in East and Central China, LEV resistance in East and Northwest China, and MNZ resistance in North and Southwest China all increased significantly over time, while AMX and TET resistance in East China notably decreased. CLA + MNZ, LEV + MNZ, and CLA + LEV dual resistance rates in China reached 14.05% (95%CI: 10.70%-17.77%), 15.12% (95%CI: 11.53%-19.10%), and 5.16% (95%CI: 2.87%-8.06%), respectively. CLA + LEV + MNZ, LEV + MNZ + AMX, and CLA + MNZ + AMX triple resistance rates were 10.36% (95%CI: 7.45%-13.69%), 0.92% (95%CI: 0.12%-2.44%), and 0.85% (95%CI: 0.20%-1.92%), respectively.

CONCLUSION

H. pylori resistance is serious in China, with MNZ resistance rate being the highest, followed by CLA and LEV resistance rates. The detection rate of some multi-resistant organisms has also reached a high level. Antibiotic resistance rates vary slightly across different regions of China, and most of them show an increasing trend over time.

Molecular Characterization and Mutational Analysis of Clarithromycin- and Levofloxacin-Resistance Genes in Helicobacter pylori from Gastric Biopsies in Southern Croatia

Point mutations in the 23S rRNA, gyrA, and gyrB genes can confer resistance to clarithromycin (CAM) and levofloxacin (LVX) by altering target sites or protein structure, thereby reducing the efficacy of standard antibiotics in the treatment of Helicobacter pylori infections. Considering the confirmed primary CAM and LVX resistance in H. pylori infected patients from southern Croatia, we performed a molecular genetic analysis of three target genes (23S rRNA, gyrA, and gyrB) by PCR and sequencing, together with computational molecular docking analysis. In the CAM-resistant isolates, the mutation sites in the 23S rRNA gene were A2142C, A2142G, and A2143G. In addition, the mutations D91G and D91N in GyrA and N481E and R484K in GyrB were associated with resistance to LVX. Molecular docking analyses revealed that mutant H. pylori strains with resistance-related mutations exhibited a lower susceptibility to CAM and LVX compared with wild-type strains due to significant differences in non-covalent interactions (e.g., hydrogen bonds, ionic interactions) leading to destabilized antibiotic-protein binding, ultimately resulting in antibiotic resistance. Dual resistance to CAM and LVX was found, indicating the successful evolution of H. pylori resistance to unrelated antimicrobials and thus an increased risk to human health.

Drug-Resistant Helicobacter pylori: Diagnosis and Evidence-Based Approach

Helicobacter pylori (H. pylori) is the most common chronic bacterial infection, affecting approximately half of the world's population. H. pylori is a Class I carcinogen according to the World Health Organization, and the International Agency for Research on Cancer (IARC) has linked it to 90% of stomach cancer cases worldwide. The overall pattern points to a yearly reduction in eradication rates of H. pylori with the likelihood of success further decreasing after each unsuccessful therapeutic effort. Antimicrobial resistance in Helicobacter pylori is a major public health concern and is a predominant cause attributed to eradication failure. As a result, determining H. pylori's antibiotic susceptibility prior to the administration of eradication regimens becomes increasingly critical. Detecting H. pylori and its antimicrobial resistance has traditionally been accomplished by time-consuming culture and phenotypic drug susceptibility testing. The resistance of H. pylori to different antibiotics is caused by various molecular mechanisms, and advances in sequencing technology have greatly facilitated the testing of antibiotic susceptibility to H. pylori. This review will summarize H. pylori antibiotic resistance patterns, mechanisms, and clinical implications. We will also review the pros and cons of current antibiotic susceptibility testing methods. Along with a comparison of tailored susceptibility-guided regimens and empirical therapy based on the latest evidence, an evidence-based approach to such situations will be explored.

The prevalence of clarithromycin-resistant Helicobacter pylori isolates: a systematic review and meta-analysis

Background

Knowledge of global clarithromycin (CLA)-resistant rates of Helicobacter pylori (H. pylori) is crucial for decision of the most appropriate eradication therapies with good clinical outcomes. Therefore, this review and meta-analysis aimed to evaluate the global prevalence of the CLA resistance in H. pylori to provide some guidance for selecting the first-line antibiotics.

Method

A comprehensive search was performed for relevant literature until April 2021 in PubMed, Embase, and Web of Science databases. Freeman-Tukey double arcsine transformation was performed to estimate the weighted pooled prevalence of resistance.

Results

The meta-analysis included 248 articles. The prevalence of CLA-resistant H. pylori was 27.53% (95% CI [25.41-29.69]). The heterogeneity between reports was significant (I² = 97.80%, P < 0.01). The resistance rate increased from 24.28% in 2010-2017 to 32.14% in 2018-2021 (P < 0.01). Iran, with 38 articles, has the most report. Nevertheless, Switzerland, Portugal, and Israel had the highest resistance rates (67.16%, 48.11%, and 46.12%, respectively). The heterogeneity between the continents and the antimicrobial susceptibility methods also interpreted standard guidelines and breakpoints was insignificant (P > 0.05).

Conclusion

Overall CLA resistance rate was 27.53%, worldwide. The difference in CLA resistance rate among the included studies can be due to several reasons such as differences in antibiotic prescription rates in various geographic areas, use of different breakpoints or inaccurate criteria in performed studies, and the emergence of multidrug-resistant (MDR) strains.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Real-time PCR detection of Helicobacter pylori clarithromycin resistance in Thrace, Greece

BACKGROUND

Growing resistance to clarithromycin is a major concern regarding treating Helicobacter pylori (H. pylori) infection. Resistance rates have a great variation even in different geographic areas within the same country and are associated with point mutations of the microbial 23S rRNA (A2142C, A2142G, and A2143G). Given the absence of available data in Thrace, the objective of this study was to estimate the resistance of H. pylori to clarithromycin and identify specific mutations that contribute to clarithromycin resistance.

METHODS

In this prospective study, we enrolled consecutive patients referred for dyspeptic complaints who underwent upper gastrointestinal endoscopy over two years. Gastric biopsies from corpus and antrum were initially tested for the presence of urease by a rapid urease test. Urease positive samples were followed by real-time PCR to confirm the presence of H. pylori and to detect point mutations.

RESULTS

A total of one hundred and thirty patients were included in the study (72 women and 58 men). Resistance to clarithromycin was detected at 23.2 %. Neither gender nor age was independently correlated with resistance rate in our patient group. The most common mutations were A2142G and A2143G.

CONCLUSIONS

A high rate of H. pylori resistance to clarithromycin was observed in our region, implicating that it should be addressed in accordance with the recommendations provided by national and international guidelines. Molecular testing should be considered an integral tool for effective monitoring in case of suspected antibiotic resistance. HIPPOKRATIA 2021, 25 (2):51-55.