Clarithromycin resistance in Helicobacter pylori and its molecular determinants in Northern Spain, 2013-2015

Detection by Real-Time PCR of Helicobacter pylori and Clarithromycin Resistance Compared to Histology on Gastric Biopsies

The global rise in Helicobacter pylori (H. pylori)-related gastric complications is largely driven by increasing antimicrobial resistance and treatment failures. As a result, accurate diagnosis followed by effective treatment is crucial. We analyzed 232 gastric biopsy samples from patients undergoing endoscopy during the method validation phase, followed by 502 samples in the routine evaluation phase. Each sample was tested using the Allplex™ H. pylori and ClariR Assay on a CFX96™ real-time PCR (RT-PCR) system, with results processed through Seegene Viewer software. In the validation phase, RT-PCR results were compared to bacterial culture, while in the routine phase, they were compared to histology. The sensitivity and specificity for H. pylori detection were 100% and 96.05% (95% Confidence Interval [CI]: 93.38-98.73), respectively. For clarithromycin resistance detection, the sensitivity and specificity were 100% and 93.33% (95% CI: 84.4-100). Additionally, RT-PCR identified 11 positive samples (10.89%) that histology failed to detect. Incorporating the Allplex™ H. pylori and ClariR Assay into our laboratory workflow improved efficiency, reduced turnaround time (TaT), and proved to be more sensitive than both culture and histology combined.

The Prevalence, Risk Factors, and Antimicrobial Resistance Determinants of Helicobacter pylori Detected in Dyspeptic Patients in North-Central Bangladesh

Chronic infection of Helicobacter pylori represents a key factor in the etiology of gastrointestinal diseases, with high endemicity in South Asia. The present study aimed to determine the prevalence of H. pylori among dyspeptic patients in north-central Bangladesh (Mymensingh) and analyze risk factors of infection and antimicrobial resistance (AMR) determinants in the pathogen. Endoscopic gastrointestinal biopsy samples were collected from dyspeptic patients for a one-year period from March 2022 and were checked for the presence of H. pylori via the rapid urease test and PCR and further analyzed for the status of virulence factors vacA/cagA and genetic determinants related to AMR via PCR with direct sequencing or RFLP. Among a total of 221 samples collected, 80 (36%) were positive for H. pylori, with the vacA+/cagA+ genotype being detected in almost half of them. H. pylori was most prevalent in the age group of 41-50-year-olds, with it being more common in males and rural residents with a lower economic status and using nonfiltered water, though the rates of these factors were not significantly different from those of the H. pylori-negative group. Relatively higher frequency was noted for the A2147G mutation in 23S rRNA, related to clarithromycin resistance (18%, 7/39). Amino acid substitutions in PBP-1A (T556S) and GyrA (N87K and D91N) and a 200 bp deletion in rdxA were detected in samples from some patients with recurrence after treatment with amoxicillin, levofloxacin, and metronidazole, respectively. The present study describes the epidemiological features of H. pylori infection in the area outside the capital in Bangladesh, revealing the spread of AMR-associated mutations.

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.

Surveillance of Helicobacter pylori resistance over 22 Years (2000-2021) in Northern Spain

OBJECTIVES

Helicobacter pylori gastritis is considered an infectious disease, regardless of symptoms and stage of disease. Most consensus documents recommend empirical therapy based on local antimicrobial susceptibility patterns. We aimed to provide clinically useful information about primary and secondary antimicrobial resistance to antimicrobials commonly prescribed for H. pylori.

METHODS

Overall, 31,406 gastroduodenal biopsies and 2,641 string tests from patients over 15 years of age were plated on selective media, isolating H. pylori in 36.7% of biopsies and 50.7% of string tests. Susceptibility testing could be performed in 96.6% (12,399/12,835) of H. pylori isolates. Polymerase chain reaction (PCR) was also used to detect H. pylori and its resistance to clarithromycin, providing susceptibility data for 112 patients with negative culture results.

RESULTS

Resistance to amoxicillin and tetracycline was unusual (0.6% and 0.2%, respectively). Rates of primary resistance to clarithromycin and metronidazole remained steady over the 22-year study period, at around 14% for clarithromycin and 30% for metronidazole, while primary resistance to levofloxacin tripled (from 7.6% in 2000 to 21.7% in 2021, P < 0.001) and increased with patient age. Notably, 1.8% of isolates were multiresistant to clarithromycin, metronidazole, and levofloxacin. Overall, secondary resistance rates were higher (P < 0.0001) than primary resistance rates for clarithromycin (42.5% vs 14.1%), metronidazole (40.9% vs 32%), and levofloxacin (21.5% vs 17.1%).

CONCLUSION

Determination of susceptibility for H. pylori by culture and/or PCR in patients undergoing endoscopy could facilitate the implementation of tailored therapy and guide the choice of empirical therapy when susceptibility testing cannot be performed, potentially helping limit the emergence of antimicrobial resistance.

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.

Tailored Helicobacter pylori eradication based on prior intake of macrolide antibiotics allows the use of triple therapy with optimal results in an area with high clarithromycin resistance

BACKGROUND

the previous intake of macrolide antibiotics is associated with a failure to eradicate Helicobacter pylori (H. pylori) with clarithromycin-containing regimens. However, the standard triple therapy achieves eradication rates of over 90% in patients without a previous use of macrolides in our health area. The aim of this study was to evaluate the efficacy of an H. pylori eradication strategy based on the intake of macrolides by the patient during the previous years.

METHODS

one hundred and sixty-nine patients with H. pylori infection were prospectively included in the study. The electronic medical record of each patient was reviewed at the time of inclusion. Depending on their previous intake of macrolides, patients were assigned to one of two eradication regimens: group A) patients without a previous intake of macrolides received an optimized triple therapy for 14 days; and group B) patients with a previous intake of macrolides received bismuth quadruple therapy for ten days.

RESULTS

ninety-one patients (53.84%) without a previous intake of macrolides received an optimized triple therapy (group A) and 78 patients (46.15%) with a previous intake of macrolides received bismuth quadruple therapy (group B). In group A, the H. pylori eradication rates were 90.11% in the intention-to-treat and 95.35% in the per-protocol analysis. In group B, the H. pylori eradication rates were 85.89% in the intention-to-treat and 98.5% in the per-protocol analysis. The overall eradication rates obtained using this strategy were 88.16% (95% CI: 82.32-92.02%) in the intention-to-treat and 96.75% (95% CI: 92.59-98.94%) in the per-protocol analysis.

CONCLUSIONS

an H. pylori eradication strategy based on the intake of macrolides during the previous years achieves overall eradication rates close to 90% and allows the use of standard triple therapy in more than half of the patients from a health area with a high level of clarithromycin resistance.

Primary Resistance Pattern of Helicobacter pylori to Antibiotics in Adult Population: A Systematic Review

Background

Helicobacter pylori is a spiral-shaped gram-negative bacteria associated with peptic ulcer, gastritis and gastric cancer. The global burden and occurrence of H. pylori infection remains prevalent and worldwide. Despite this, the trend of the bacterial resistance is not recently studied which can help in the adoption of global, regional and local prevention strategies.

Objective

The aim of the study was to systematically review the existing published literature that presents the estimate of H. pylori antibiotic resistance.

Methods

A protocol was primarily registered in PROSPERO International prospective register of systematic reviews and has given a registration number CRD42017068710. It was registered after checking whether there was similar study being conducted. A database search (PubMed/Medline and Google scholar) was used to collect relevant articles. A standardized form was prepared for the extraction of relevant data from studies which fulfilled the eligibility criteria. A National Institute for Health research (NIH)-based quality assessment tool was utilized to assess the quality of studies included in the study.

Results

Our searching process has retrieved a total of 288 publications which later resulted in 38 articles for full-text review. Among the 38 articles reviewed in full text, 14 studies were included which fulfilled the inclusion criteria. H.pylori-pooled overall prevalence rate of antibiotic resistance was found to be 4.55% (95% confidence interval (CI): 3.96–5.22%) to amoxicillin, 27.22% (95% CI: 25.89–28.58%) to clarithromycin, 39.66% (95% CI: 38.20–41.15%) to metronidazole, and 22.48% (95% CI: 21.24–23.76%) to levofloxacin.

Conclusion

The primary antibiotic resistance pattern of H. pylori is increasing worldwide. Thus, implementation of local drug susceptibility surveillance program, rational prescribing and use of antibiotics are necessary.

Helicobacter pylori pathogenicity and primary antimicrobial resistance in Northern Spain

BACKGROUND

Helicobacter pylori infection is associated with chronic gastritis, ulcers and gastric cancer. Antimicrobial resistance has increased worldwide affecting the efficacy of current treatments. Most guidelines recommend implementation of regional surveillance of primary antibiotic resistance of H pylori. Only a fraction of individuals infected with H pylori develop gastric diseases which are related to virulence factors of the bacteria. The aims of the study were to determine the primary antimicrobial resistance rates of H pylori and to know the virulence factors prevalence of strains circulating in Southern Europe.

MATERIALS AND METHODS

Susceptibility testing by Etest to clarithromycin, levofloxacin, metronidazole, amoxicillin and tetracycline was performed in 102 isolates (99 naïve patients). The prevalence of virulence factors (cagA, vacA, oipA, babA and dupA) was evaluated in 102 H pylori isolates from patients with mild-disease symptoms and in 22 isolates from patients with severe-disease symptoms.

RESULTS

Primary resistance rates were 12.1% to clarithromycin, 13.1% to levofloxacin, 24.2% to metronidazole and 0% to amoxicillin and tetracycline. Combined resistance to clarithromycin and levofloxacin was 3% and to clarithromycin and metronidazole 4%. Prevalence of virulence factors in the mild- and severe-disease group was 35.3% and 81.8% for cagA, 20.6% and 54.5% for cagA/vacAs1m1, 94.1% and 95.4% for babA2, 78.4% and 100% for oipA and 30.4% and 18.2% for dupA.

CONCLUSIONS

Primary antimicrobial resistance rates were under 15% for clarithromycin and levofloxacin. The prevalence of H pylori carrying the virulent genotype cagA/vacAs1m1 was higher than 20% in the mild-disease and 54% in the severe-disease symptom group.

Helicobacter pylori antimicrobial resistance during a 5-year period (2013-2017) in northern Spain and its relationship with the eradication therapies

BACKGROUND

Antibiotic resistance is the main cause for Helicobacter pylori therapy failure. Frequently, empirical regimens have been recommended in patients with various H. pylori eradication failures. In patients with H. pylori-resistant to various families of antibiotics, the treatment guided by antimicrobial susceptibility testing allows the achievement of good eradication rates.

AIM

To evaluate the effectiveness of susceptibility-guided antimicrobial treatment for H. pylori infection in patients with resistance to one or various families of antibiotics.

METHODS

A total of 3170 consecutive patients infected by H. pylori during 2013-2017 were tested for antimicrobial susceptibility. 66.6% patients showed resistance to one antimicrobial, 18.9% to two, and 2.4% to three families of antibiotics. A cohort of 162 H. pylori-positive patients were enrolled in this study. Forty-three with single H. pylori resistance to clarithromycin (CLR) were treated with omeprazole (PPI), amoxicillin (AMX), and levofloxacin (LVX)-OAL (31 subjects) or omeprazole, AMX, and metronidazole (MTZ)-OAM (12 patients) and 77 patients with dual H. pylori resistance (51 to CLR and MTZ, 12 to CLR plus LVX, and 14 to MTZ plus LVX) received OAL or OBTM (PPI, bismuth subcitrate, tetracycline, and MTZ), OAM, and OAC, respectively. Other 42 patients with triple H. pylori resistance (CLR, LVX, and MTZ) were treated with PPI, AMX, and rifabutin-OAR (18 subjects), PPI, AMX, and doxycycline-OAD (8), OADB (7), OBTM (6), and ODBR (3). All subjects received standard doses for 10 days. Eradication rate was confirmed by 13 C-UBT. Adverse events were assessed by a questionnaire.

RESULTS

Intention-to-treat analysis demonstrates that eradication rates using triple therapies in patients with H. pylori resistance to one and to two families of antibiotics were 93% and 94.8%, respectively. In subjects with H. pylori-resistant to three families of antibiotics, cure rate was higher in naïve patients treated with OAR-10 days compared to those treated with bismuth-containing quadruple therapies (90% vs 75%). Adverse events were limited (18 of 162, 11.1%), all of them mild-moderate.

CONCLUSIONS

The implementation of susceptibility-guided triple therapy for 10 days leads to eradication rate ≥95% in naïve patients with H. pylori resistance to one or two families of antimicrobials. In naïve patients with H. pylori resistance to three families, OAR treatment achieved a 90% of eradication.

The Resistance Rate of Helicobacter Pylori to Clarithromycin and Main Mutations on Bacterial Genomic Responsible for Bacterial Resistance: A Comparative Study in Children and Adults, Tehran and Iran

BACKGROUND

High resistance to common antibiotics has become a huge global dilemma in eradicating Helicobacter Pylori infection in both children and adults. The great concern is about the resistance to different classes of antibiotics especially Clarithromycin because of its widespread use.

OBJECTIVES

The present survey aimed to assess the resistance rate to Clarithromycin in Helicobacter Pylori isolated in patients aged less than 15 years as compared to patients older than 15 years of age.

METHODS

In this cross-sectional study, total 72 patients with upper gastrointestinal symptoms requiring diagnostic endoscopy referred to Rasoul-e-Akram Hospital in Tehran during one year (August 2015 to August 2016). Helicobacter Pylori infection was diagnosed in patients using the Rapid Urease Test. The antibiotics resistance was detected in genomes using the real-time polymerase chain reaction (PCR) on 23S rRNA gene.

RESULTS

In total 72 patients, 36 cases aged less than or equal to 15 years and 36 patients were older than 15 years. Of all patients in this study, 17 cases were detected with gene mutations or polymorphisms related to resistance to Clarithromycin. Overall prevalence rate of resistance was reported 23.61%. Three polymorphisms on 23S rRNA gene including A2142G, A2142C, and A2143G were revealed in 47.1%, 5.9%, and 47.1% of patients, respectively. The bacterial resistance to Clarithromycin was observed more prevalent in patients that aged older than 15 years compared to patients younger than 15 years of age. Also, frequent consumption of any type of antibiotics was significantly associated with the higher resistance of bacterium to Clarithromycin.

CONCLUSION

The results of our study regarding the resistance of Helicobacter Pylori to Clarithromycin were similar to findings of other studies around the world. But, the Clarithromycin resistance rate was reported higher in patients older than 15 years of age and those patients who repeatedly received different types of antibiotics regardless of their age. Of all mutations in bacterial genome, the prominent mutations responsible for bacterial resistance to Clarithromycin included A2142C, A2142G, and A2143G nucleotide polymorphism on 23S rRNA gene.

Helicobacter pylori and some aspects of gut microbiota in children

Helicobacter pylori infection in children differs from infection in adults in many aspects. The rate of infection, epidemiology, clinical presentations and complications, the applicability of diagnostic tests, antibiotic resistance, treatment options, and success rates differ significantly. Due to all these differences, management guidelines for children and adults differ also substantially. In 2017, the Updated ESPGHAN and NASPGHAN Guidelines on the management of H. pylori infection in children were published, emphasizing the differences in clinical presentation and indications for treatment, stating that the primary goal of clinical investigation in children is to identify the cause of upper gastrointestinal symptoms rather than the presence of H. pylori infection. Therefore, the diagnosis should be based on upper endoscopy, and the "test and treat strategy" should not be used in children. Due to an increasing rate of antibiotic resistance worldwide, the updated guidelines recommend broader use of antimicrobial susceptibility testing for H. pylori strains in order to tailor eradication treatment accordingly. Moreover, treatment in children should be prescribed only when indicated and should be based on the rate of eradication in local populations aiming for treatment success above 90%. During the last two decades there has been a steady decrease in the rate of H. pylori infection in both children and adults in the Western world. Two recent publications studying the incidence of H. pylori infection confirmed that early childhood is a time for acquisition of infection both in industrialized and nonindustrialized countries. In addition, they showed that H. pylori could be acquired outside the family. In respect to the inverse association between H. pylori and allergy, a longitudinal study demonstrated that early exposure to H. pylori at any age was inversely associated with atopy and allergic conditions.

Prevalence of clarithromycin resistance in Helicobacter pylori in Santiago, Chile, estimated by real-time PCR directly from gastric mucosa

BACKGROUND

Current available treatments for Helicobacter pylori eradication are chosen according to local clarithromycin and metronidazole resistance prevalence. The aim of this study was to estimate, by means of molecular methods, both clarithromycin and metronidazole resistance in gastric mucosa from patients infected with H.pylori.

METHODS

A total of 191 DNA samples were analyzed. DNA was purified from gastric mucosa obtained from patients who underwent an upper gastrointestinal endoscopy at an university hospital from Santiago, Chile, between 2011 and 2014. H.pylori was detected by real-time PCR. A 5'exonuclease assay was developed to detect A2142G and A2143G mutations among H.pylori-positive samples. rdxA gene was sequenced in samples harboring A2142G and A2143G mutations in order to detect mutations that potentially confer dual clarithromycin and metronidazole resistance.

RESULTS

Ninety-three (93) out of 191 DNA samples obtained from gastric mucosa were H.pylori-positive (48.7%). Clarithromycin-resistance was detected in 29 samples (31.2% [95%CI 22.0-41.6%]). The sequencing of rdxA gene revealed that two samples harbored truncating mutations in rdxA, one sample had an in-frame deletion, and 11 had amino acid changes that likely cause metronidazole resistance.

CONCLUSIONS

We estimated a prevalence of clarithomycin-resistance of 31.8% in Santiago, Chile. Three of them harbor inactivating mutations in rdxA and 11 had missense mutations likely conferring metronidazole resistance. Our results require further confirmation. Nevertheless, they are significant as an initial approximation in re-evaluating the guidelines for H.pylori eradication currently used in Chile.

Primary antibiotic resistance and its relationship with cagA and vacA genes in Helicobacter pylori isolates from Algerian patients

The epidemiology of Helicobacter pylori resistance to antibiotics is poorly documented in Africa and especially in Algeria. The aim of our study was to determine the antibiotic resistance rates, as well as its possible relationship with VacA and CagA virulence markers of isolates from Algerian patients. One hundred and fifty one H. pylori isolate were obtained between 2012 and 2015 from 200 patients with upper abdominal pain. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, ciprofloxacin, rifampicin and tetracycline. Molecular identification of H. pylori and the detection of vacA and cagA genes were performed using specific primers. We found that H. pylori was present in 83.5% of collected biopsies, 54.9% of the samples were cagA positive, 49.67% were vacA s1m1, 18.30% were vacA s1m2 and 25.49% were vacA s2m2. Isolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), rifampicin (0%), a high rate of resistance to metronidazole (61.1%) and a lower rate of resistance to clarithromycin (22.8%) and ciprofloxacin (16.8%). No statically significant relationship was found between vagA and cagA genotypes and antibiotic resistance results (p > 0.5) except for the metronidazole, which had relation with the presence of cagA genotype (p = 0.001).

Macrolide use in the previous years is associated with failure to eradicate Helicobacter pylori with clarithromycin-containing regimens

BACKGROUND

There is some evidence that prior use of macrolide antibiotics is a useful predictor of the likelihood of standard triple therapy failure in Helicobacter pylori eradication. In this study, we have evaluated whether previous intake of macrolides correlates with failure to eradicate H. pylori using two different first-line clarithromycin-containing regimens.

MATERIALS AND METHODS

Retrospective study of 212 patients with H. pylori infection treated with one of two first-line clarithromycin-containing regimens: 108 patients treated with triple therapy for 10 days and 104 patients treated with concomitant therapy for 10 days. The intake of macrolides (clarithromycin, azithromycin, and other macrolides) prior to the eradication therapy was obtained from the electronic medical record, which contains information regarding all the medication prescribed to the patients since the year 2004.

RESULTS

One hundred of 212 patients (47.2%) had received at least one treatment with macrolides during the years prior to the eradication therapy. H. pylori eradication rates were significantly lower in patients with previous use compared to patients without previous use of macrolides, both with triple therapy (60.8% vs 92.9%; P < .0001) and with concomitant therapy (85.7% vs 98.2%; P = .024).

CONCLUSIONS

Previous use of macrolides correlates with a low H. pylori eradication rate with triple and concomitant clarithromycin-containing regimens. In addition, our study shows that in patients without previous use of macrolides, triple therapy achieves per-protocol eradication rates over 90%.

High primary antibiotic resistance of Helicobacter Pylori strains isolated from dyspeptic patients: A prevalence cross-sectional study in Spain

BACKGROUND

The rate of H. pylori resistance to different antibiotics is increasing and determines the selection of eradication therapy. The aim of this study was to determine the resistance patterns of H. pylori strains in our area.

METHODS

Biopsies from gastric corpus for microbiological culture and antibiotic resistance were obtained in patients undergoing upper gastrointestinal endoscopy for dyspepsia. Selective Agar Pylori for isolation of the bacteria and Agar Mueller-Hinton supplemented with blood to test the sensitivity to antibiotics were used. Presence of H. pylori was confirmed using direct observation with phase-contrast microscopy and/or smears stained with acridine orange. In vitro bacterial susceptibility to amoxicillin, clarithromycin, rifampicin, tetracycline, metronidazole, and levofloxacin was tested using diffusion MIC test strips. Minimum inhibitory concentration values were determined based on the 6th version of the EUCAST (European Committee on Antimicrobial Susceptibility Testing) Clinical Breakpoint (2016).

RESULTS

Two hundred and seventeen patients were included (58.1% female, median age 64 years, range 25-92). H. pylori was identified in 108 patients (49.8%); culture and antibiogram were completed in 77 of them (71.3% of H. pylori-positive patients). The resistance rates were as follows: levofloxacin 38.7%, rifampicin 33.3%, metronidazole 27% and clarithromycin 22.4%. No case of amoxicillin or tetracycline resistance was identified. Dual clarithromycin-metronidazole resistance was observed in 10% of strains, whereas multiple drug-resistant was observed in 14.2%.

CONCLUSIONS

Resistance rate of H. pylori to antibiotics is high in the northwest of Spain. The high resistance to levofloxacin and clarithromycin advises against their wide empirical use of these antibiotics in eradication regimens.

Diagnosis of Helicobacter pylori infection

Important progress is being made in endoscopic methods which allow clinicians to predict the presence of Helicobacter pylori based on characteristics of gastric mucosa and to obtain targeted biopsies. There are also important developments in molecular methods with various techniques derived from standard PCR, applied both on gastric biopsies and stool specimens. Progress is being made in microfluidic systems to get a reliable diagnosis in a very short time. The interest of the ¹³ C urea breath test has been confirmed as well as stool antigen tests. Attempts are being made to find biological markers of premalignant conditions by serology, other than pepsinogens.

Treatment of Helicobacter pylori infection 2017

This review summarizes important studies regarding Helicobacter pylori therapy published from April 2016 to April 2017. The main themes that emerge involve studies assessing the efficacy of bismuth and nonbismuth quadruple regimens. While in recent years, much of the emphasis on the use of bismuth has focussed on its utility in a second-line setting, an increasing number of studies this year have shown excellent efficacy in first-line therapy. The efficacy of bismuth as a second-line after sequential and concomitant therapy was particularly noteworthy. Antibiotic resistance was more intensely studied this year than for a long time, and definite trends are presented regarding an increase in resistance, including the fact that clarithromycin resistance in particular is now at a level where the continued use of clarithromycin triple therapy first-line as a mainstream treatment is not recommended. Another exciting trend to emerge this year is the utility of vonoprazan as an alternative to PPI therapy, especially in resistant and difficult-to-treat groups.

Quercetin from Polygonum capitatum Protects against Gastric Inflammation and Apoptosis Associated with Helicobacter pylori Infection by Affecting the Levels of p38MAPK, BCL-2 and BAX

Helicobacter pylori-associated gastritis is a major threat to public health and Polygonum capitatum (PC) may have beneficial effects on the disease. However, the molecular mechanism remains unknown. Quercetin was isolated from PC and found to be a main bioactive compound. The effects of quercetin on human gastric cancer cells GES-1 were determined by xCELLigence. H. pylori-infected mouse models were established. All mice were divided into three groups: control (CG, healthy mice), model (MG, H. pylori infection) and quercetin (QG, mouse model treated by quercetin) groups. IL-8 (interleukin-8) levels were detected via enzyme-linked immunosorbent assay (ELISA). Cell cycle and apoptosis were measured by flow cytometry (FCM). Quantitative reverse transcription PCR (qRT-PCR) and Western Blot were used to detect the levels of p38MAPK (38-kD tyrosine phosphorylated protein kinase), apoptosis regulator BCL-2-associated protein X (BAX) and B cell lymphoma gene 2 (BCL-2). The levels of IL-8 were increased by 8.1-fold in a MG group and 4.3-fold in a QG group when compared with a CG group. In a MG group, G0–G1(phases of the cell cycle)% ratio was higher than a CG group while S phase fraction was lower in a model group than in a control group (p < 0.01). After quercetin treatment, G0–G1% ratio was lower in a QG group than a MG group while S phase fraction was higher than a MG group (p < 0.01). Quercetin treatment reduced the levels of p38MAPK and BAX, and increased the levels of BCL-2 when compared with a MG group (p < 0.05). Quercetin regulates the balance of gastric cell proliferation and apoptosis to protect against gastritis. Quercetin protects against gastric inflammation and apoptosis associated with H. pylori infection by affecting the levels of p38MAPK, BCL-2 and BAX.