Detection of 23SrRNA Mutations Strongly Related to Clarithromycin Resistance in Helicobacter pylori Strains Isolated From Patients in the North of Iran

Association between MUC1 rs4072037 polymorphism and Helicobacter pylori in patients with gastric cancer

Background

The MUC1 gene encodes glycoproteins attached to cell membrane that play a protective role in gastric cancer and protect epithelial surfaces against external factors such as Helicobacter pylori. H. pylori infection can induce a cascade of innate and acquired immune responses in gastric mucosa. Relationship between rs4072037G>A polymorphism of MUC1 gene and increased susceptibility to H. pylori infection aimed to investigate in patients with gastric cancer in Mazandaran, northern Iran.

Methods

A case-control study was conducted on 99 patients with gastric cancer (H. pylori positive and negative) and 98 controls (H. pylori positive and negative) without gastric cancer (confirmed by pathological biopsy samples obtained during endoscopy). H. pylori infection was diagnosed by histological examination using Giemsa staining. Genomic DNA extracted from peripheral blood was analyzed by PCR-RFLP technique.

Results

Analysis of all genetic models showed no significant relationship between rs4072037G>A polymorphism and risk of gastric cancer (GC). The relationship between H. pylori infection and rs4072037G>A polymorphism showed an increased susceptibility to gastric cancer in both positive and negative H. pylori groups (including case and control groups). The genetic model of GA/GG and H. pylori- positive versus GA/GG and H. pylori-negative showed a significantly increased susceptibility to gastric cancer (OR=0.251, CI: 0.128-0.493, P=0.000).

Conclusion

These findings indicate that rs4072037G>A polymorphism may interact with H. pylori infection to increase the risk of GC.

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.

Evaluation of Mutations in 23S rRNA, rdxA and frxA Genes of Helicobacter pylori in Paraffin-Embedded Gastric Biopsy Specimens from Iranian Gastric Cancer and Gastritis Patients

PURPOSE

Helicobacter pylori (H. pylori) infection is considered as one of the main cause of gastric cancer. Treatment failure of the infection often occurs due to antibiotic resistance. Herein, we aimed to evaluate the mutations in 23S rRNA gene of H. pylori which are associated with clarithromycin resistance and in rdxA and frxA genes of the bacterium which may be associated with metronidazole resistance, in paraffin-embedded gastric biopsies from patients with gastric adenocarcinoma and gastritis in Tabriz, the northwest of Iran.

METHODS

In the study, 80 paraffin-embedded tissue sections from 40 gastric cancer and 40 gastritis patients in the Imam Reza hospital, Tabriz, Iran were collected. The existence of ureC gene was verified by PCR method. Genotypical clarithromycin resistance was investigated by real-time PCR method and determination of the melting temperature. PCR reaction and sequencing were used for the evaluation of mutations in rdxA and frxA genes.

RESULTS

The results of ureC amplification showed that DNA of H. pylori was present in the 82.66% of the obtained DNA samples. About 45.16% of samples were resistant to the clarithromycin and 53.22% of them were resistant to the metronidazole. Based on the results from real-time PCR, the frequency of mutations was as follow A2143G 64.28%, A2142G 44.44% and A2142C 1.11%. The mutations of rdxA gene were 66.66% missense, 30.30% frameshift and 3.03% non-sense. The mutations of frxA gene were 36.36% missense, 54.54% frameshift and non-sense 9.09%.

CONCLUSION

A2143G mutation is the most frequent mutation among clarithromycin resistant genes in Iran. Also, missense and frameshift mutations are frequent in rdxA and frxA genes. Screening for these mutations could help researchers to investigate the most effective anti-H. pylori antibiotics and to prevent antibiotic resistance.

The increasing antimicrobial resistance of Helicobacter pylori in Iran: A systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance of Helicobacter pylori can result in eradication failure. Metadata on the antimicrobial resistance of H pylori in Iran could help to formulate H pylori eradication strategies in Iran.

METHODS

A systematic review was performed after searching in MEDLINE, Scopus, Embase, Web of Science, and the Cochrane Library. A meta-analysis was performed, and a comparison of the rates between children and adults; time periods (1999-2010, 2011-2016, 2017-2019); and the methods used was carried out.

RESULTS

A total of 66 studies investigating 5936 H pylori isolates were analyzed. The weighted pooled resistance (WPR) rates were as follows: clarithromycin 21% (95% CI 16-26), metronidazole 62% (95% 57-67), clarithromycin in combination with metronidazole 16% (95% CI 10-23), ciprofloxacin 24% (95% CI 15-33), levofloxacin 18% (95% CI 9-30), erythromycin 29% (95% CI 12-50), furazolidone 13% (95% CI 4-27), tetracycline 8% (95% CI 5-13), and amoxicillin 15% (95% CI 9-22). During the three time periods, there was an increased resistance to amoxicillin, clarithromycin, ciprofloxacin, furazolidone, and tetracycline (P ˂ .05). Furazolidone and a clarithromycin/metronidazole combination had the higher resistance rates in children (P ˂ .05).

CONCLUSION

An increasing rate of resistance to amoxicillin, clarithromycin, ciprofloxacin, furazolidone, and tetracycline in Iranian H pylori isolates was identified. In children, the resistance to furazolidone and a combination of clarithromycin and metronidazole is higher compared to adults. As a stable, high resistance to metronidazole was found in children and adults in all Iranian provinces, we suggest that metronidazole should not be included in the Iranian H pylori eradication scheme.

Antibiotic Resistance Profiles, Molecular Mechanisms and Innovative Treatment Strategies of Acinetobacter baumannii

Antibiotic resistance is one of the biggest challenges for the clinical sector and industry, environment and societal development. One of the most important pathogens responsible for severe nosocomial infections is Acinetobacter baumannii, a Gram-negative bacterium from the Moraxellaceae family, due to its various resistance mechanisms, such as the β-lactamases production, efflux pumps, decreased membrane permeability and altered target site of the antibiotic. The enormous adaptive capacity of A. baumannii and the acquisition and transfer of antibiotic resistance determinants contribute to the ineffectiveness of most current therapeutic strategies, including last-line or combined antibiotic therapy. In this review, we will present an update of the antibiotic resistance profiles and underlying mechanisms in A. baumannii and the current progress in developing innovative strategies for combating multidrug-resistant A. baumannii (MDRAB) infections.

An Updated Systematic Review and Meta-Analysis on the Helicobacter pylori Antibiotic Resistance in Iran (2010-2020)

This updated systematic review and meta-analysis followed two objectives: (1) to determine Helicobacter pylori antibiotic resistance in Iran during 2010-2020 and (2) to assess the trend of resistance from 1997 to 2020. A systematic search in multiple databases, including ISI Web of Knowledge, PubMed, Scopus, Google Scholar, and the Scientific Information Database (SID), was performed using MeSH-extracted keywords. Meta-analysis was done on extracted data from a total of 27 included citations published between 2010 and January 20, 2020. The overall mean prevalence of H. pylori resistance was 64.9% for metronidazole, 25.3% for clarithromycin, 20.7% for amoxicillin, 16.1% for tetracycline, 21.9% for levofloxacin, 22.8% for rifampicin, 27.2% for furazolidone, 32.3% for ciprofloxacin, and 38.7% for erythromycin. In addition, the prevalence of multidrug-resistant strains of H. pylori was 26.5% in Iran. The pooled prevalence of point mutations A2143G, A2142G, and A2142C associated with clarithromycin resistance were 46.6%, 37.2%, and 5.5%, respectively; mutations in frxA and rdxA genes associated with metronidazole resistance were 46.4% and 19.7%, respectively; gyrA and gyrB genes mutations among fluoroquinolone-resistant strains were 55.3% and 48.2%, respectively; and resistance associated with integrons was 47%. According to the present findings, resistance of H. pylori to antibiotics used for eradication therapy has reached an alarming level in Iran. Furthermore, the trend of H. pylori resistance has increased between 1997 and 2020. Hence, continuous surveillance on resistance patterns, logical prescription and appropriate consumption of antibiotics, and selecting effective therapeutic regimens in accordance with local resistance patterns are required to prevent further spread of resistance and ensuing treatment failures.

Molecular Assessment of Resistance to Clarithromycin in Helicobacter pylori Strains Isolated from Patients with Dyspepsia by Fluorescent In Situ Hybridization in the Center of Iran

Background and Aims

Helicobacter pylori is a common infectious bacterium mostly found in gastroduodenal diseases. The increased prevalence of clarithromycin-resistant H. pylori strains is a major challenge in the successful treatment of infections caused by this organism. The present study is aimed at detecting the clarithromycin resistance pattern of H. pylori strains isolated from gastric biopsies and evaluating point mutations of the 23S rRNA gene. Patients and methods. In the present descriptive cross-sectional study, 165 patients with gastrointestinal disorders, who were referred to the Endoscopy Center of Dr. Shariati Hospital of Isfahan, Iran, were enrolled from April to July 2018. H. pylori infection was diagnosed by culture, and susceptibility of the isolates to clarithromycin was assessed by the E-test. Minimum inhibitory concentration (MIC) values were obtained based on EUCAST recommendations. Also, fluorescence in situ hybridization (FISH) was used to determine point mutations associated with clarithromycin resistance.

Results

By using culturing, H. pylori was isolated from 50.3% (83/165) gastric biopsy specimens. The overall frequency of resistance to clarithromycin was 25.3% (21/83) by the E-test. In the resistance genotypic analysis, 19 isolates had mutations. The prevalence of A2143G and A2144G mutations was 68.4% (13/19) and 31.5% (6/19), respectively. A2143C mutation was not tracked in any isolate. Two isolates with MIC > 0.5 μg/mL had no mutations that could be related to other mechanisms of resistance.

Conclusion

As presented in the study, the high prevalence of clarithromycin-resistant H. pylori due to point mutations of the 23S rRNA gene indicates the necessity of revising the standard treatment regimen based on antibiotic susceptibility pattern of each region.

Analysis of babA, cagE and cagA Genes in Helicobacter pylori from Upper Gastric Patients in the North of Iran

OBJECTIVE

Helicobacter pylori is a Gram-negative bacterium which has a serious effect on up to half of the world's population and has been related to different gastric diseases. The goal of this study was to assess the frequency of babA, cagE and cagA genotypes among H. pylori strains isolated from gastric biopsies of endoscopic patients in the north of Iran.

METHODS

The present study was performed on 90 strains of H. pylori isolated from patients with gastric diseases (Gastric ulcer (GU), Duodenal ulcer (DU), Gastritis (G), Non-ulcer dyspepsia (NUD) and Gastric adenocarcinoma (GC)). DNA was extracted from all isolated strains and PCR method was performed to detect the prevalence of babA2, cagE and cagA genes using specific primers.

RESULTS

Among 90 samples of H. pylori, babA2, cagE, and cagA genes were detected in 42.2%, 30% and 82.2% of strains respectively. The statistical analysis showed that the prevalence of cagA gene in GU, G, DU, and NUD was significantly higher than other genes. Moreover, cagA, and babA2 genes were significantly more prevalent in GC patients compared to cagE gene. Our isolates exhibited 8 distinct arrangements of virulence patterns. The occurrence of cagA (35.6%) was the most prevalent pattern followed by cagA/babA2 (20%) and cagA/babA2/cagE (14.4%).

CONCLUSION

In summary, as first report from Guilan province in the north of Iran, we showed significant association between the presence of babA2, cagE, and cagA genes in different types of gastric disorders.

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.

A systematic review and meta-analysis of genotypic methods for detecting antibiotic resistance in Helicobacter pylori

BACKGROUND

Antibiotic susceptibility testing is essential for tailored treatments to cure Helicobacter pylori (H. pylori) infection. However, phenotypic methods have some limitations.

OBJECTIVES

To evaluate the feasibility of genotypic detection methods compared with phenotypic detection methods using samples taken from H. pylori-infected patients.

METHODS

Literature searches were conducted in the following databases (from January 2000 to November 2016): PubMed, Embase, the Cochrane Library, and Web of Science. A meta-analysis and systematic review was performed for studies that compared genotypic methods with phenotypic methods for the detection of H. pylori antibiotic susceptibility.

RESULTS

This meta-analysis showed that the pooled sensitivity, specificity, and diagnostic odds ratio (DOR) for the A2142G/C and/or A2143G combination for the detection of clarithromycin resistance in the strain samples were 0.97 (95% CI: 0.94-0.99), 1.00 (95% CI: 0.99-1.00), and 13 742 (95% CI: 1708-110 554), respectively. The pooled sensitivity, specificity, and DOR for the A2142G/C and/or A2143G combination for the detection of clarithromycin resistance in biopsy samples were 0.96 (95% CI: 0.90-0.99), 0.96 (95% CI: 0.91-0.99), and 722 (95% CI: 117-4443), respectively. The summarized sensitivity, specificity, and DOR value for the ability of the genotypic methods to detect quinolone resistance in biopsy specimens were 0.97 (95% CI: 0.87-0.99), 0.99 (95% CI: 0.92-1.00), and 6042 (95% CI: 486-75 143), respectively.

CONCLUSION

The genotypic detection methods were reliable for the diagnosis of clarithromycin and quinolone resistance in the strain and biopsy specimens. The A2142G/C and/or A2143G combination had the best sensitivity and specificity for the detection of clarithromycin resistance.

Antimicrobial resistance mechanisms and potential synthetic treatments

Since the discovery of antibiotics by Sir Alexander Fleming they have been used throughout medicine and play a vital role in combating microorganisms. However, with their vast use, development of resistance has become more prevalent and their use is currently under threat. Antibiotic resistance poses a global threat to human and animal health, with many bacterial species having developed some form of resistance and in some cases within a year of first exposure to antimicrobial agents. This review aims to examine some of the mechanisms behind resistance. Additionally, re-engineering organisms, re-sensitizing bacteria to antibiotics and gene-editing techniques such as the clustered regularly interspaced short palindromic repeats-Cas9 system are providing novel approaches to combat bacterial resistance. To that extent, we have reviewed some of these novel and innovative technologies.

In 1928, penicillin was discovered, changing the field of modern medicine as it provided an opportunity to treat microbial infections. Since then, microorganisms such as bacteria have evolved and now have the ability to resist a wide variety of agents that might otherwise prevent their growth. By 2050, it is estimated that around 10 million lives each year will be lost due to these bacteria. This article provides an insight into how bacteria resist antibiotics and potential new methods of treating these organisms.

Resistance mechanisms of Helicobacter pylori and its dual target precise therapy

Helicobacter pylori drug resistance presents a significant challenge to the successful eradication of this pathogen. To find strategies to improve the eradication efficacy of H. pylori, it is necessary to clarify the resistance mechanisms involved. The mechanisms of H. pylori drug resistance can be investigated from two angles: the pathogen and the host. A comprehensive understanding of the molecular mechanisms of H. pylori resistance based on both pathogen and host would aid the implementation of precise therapy, or ideally "dual target precise therapy" (bacteria and host-specific target therapy). In recent years, with increased understanding of the mechanisms of H. pylori resistance, the focus of eradication has shifted from disease-specific to patient-specific treatment. The implementation of "precision medicine" has also provided a new perspective on the treatment of infectious diseases. In this article, we systematically review current research on H. pylori drug resistance from the perspective of both the pathogen and the host. We also review therapeutic strategies targeted to pathogen and host factors that are aimed at achieving precise treatment of H. pylori.

GenoType® HelicoDR test in comparison with histology and culture for Helicobacter pylori detection and identification of resistance mutations to clarithromycin and fluoroquinolones

BACKGROUND

There are several methods for Helicobacter pylori infection diagnosis.

AIM

The efficacies of three methods for H. pylori identification directly from a biopsy were compared: histology, culture, and molecular GenoType® HelicoDR test.

MATERIALS & METHODS

Eighty-five triplicates of stomach antrum biopsies were obtained during gastroscopy procedures for culture, histology, and molecular assay. In addition, we performed molecular identification of genes encoding resistance to clarithromycin and fluoroquinolones.

RESULTS

The results have shown that the most specific method with the highest number of positive specimens was by molecular kit, compared to culture and histology (94.3%, 77.1%, and 71.4%, respectively). There was a higher rate of resistance mutations to clarithromycin than to fluoroquinolones (68.26% vs 20%). The most common mutations for clarithromycin and fluoroquinolones resistance were found in alleles A2143G and N87K, respectively. The highest rate of positive specimens was identified by the molecular.

DISCUSSION

GenoType HelicoDR kit (94.3%), which has several advantages: direct identification, strain resistance characterization, mixture of genotypes detection, and no transport or storage limitations; thus, it is an excellent epidemiological screening tool. This work has demonstrated a lower resistance rate to fluoroquinolones; it is possible that in the investigated geographic area treatment with fluoroquinolones may be preferable to clarithromycin. GenoType® HelicoDR test eliminates the need for culture performance and susceptibility tests for several common antibiotic agents and enables optimal and specific antibiotic treatment adjustment.

CONCLUSION

We recommend a combination of PCR assay and bacterial culture for a quick method of screening and more efficient identification of H. pylori strains and resistance patterns.