scholarly journals Antibiotic Susceptibilities ofHelicobacter pyloriStrains Isolated in the Province of Alberta

1998 ◽  
Vol 12 (4) ◽  
pp. 295-298 ◽  
Author(s):  
Diane E Taylor ◽  
Qin Jiang ◽  
Richard N Fedorak
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Gastric Biopsy ◽  
Minimal Inhibitory Concentrations ◽  
Antibiotic Susceptibilities ◽  
Biopsy Specimens ◽  
Metronidazole Resistance ◽  
Agar Dilution ◽  
Resistant Strains ◽  
H Pylori

The incidence of antibiotic resistance to amoxicillin, clarithromycin, erythromycin, metronidazole and tetracycline inHelicobacter pyloristrains isolated from gastric biopsy specimens obtained in Alberta was investigated. Results for all antibiotics were obtained using agar dilution, and in addition to metronidazole, the E test was used. Resistance to amoxicillin and tetracycline was not detected. Metronidazole resistance determined using agar dilution was approximately 12% (95% CI 4% to 26%) when minimal inhibitory concentrations (MICs) were at least 8 µg/mL, but fell to 2% (95% CI 0.1% to 13%) when MICs were set at 32 µg/mL or greater. The E test for metronidazole resistance (MIC 8 µg/mL or greater) yielded a slightly higher percentage of resistant strains compared with agar dilution tests (14%, 95% CI 5% to 29%). One of the 31 strains was resistant to clarithromycin (MIC 8 µg/mL) and erythromycin (MIC 16 µg/mL). Thus, the incidence of resistance to clarithromycin, part of the currently used triple therapy for eradication ofH pylori, was 3% (95% CI 0.1% to 17%).

scholarly journals Resistotype of Helicobacter pylori isolates: the impact on eradication outcome

2014 ◽  
Vol 63 (5) ◽  
pp. 703-709 ◽  
Author(s):  
Hanafiah Alfizah ◽  
Ahmad Norazah ◽  
Razlan Hamizah ◽  
Mohamed Ramelah
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Eradication Therapy ◽  
Fluoroquinolone Resistance ◽  
23S Rrna ◽  
Nonsense Mutations ◽  
Metronidazole Resistance ◽  
Resistant Strains ◽  
H Pylori ◽  
The Impact

Antibiotic resistance is increasing worldwide, and it has been regarded as the main factor reducing the efficacy of Helicobacter pylori therapy. The aim of this study was to determine the phenotype and genotype of antibiotic-resistant strains of H. pylori in the Malaysian population and to evaluate the impact of antibiotic resistance to eradication outcome. One hundred and sixty-one H. pylori isolates were analysed in this study. Metronidazole, clarithromycin, fluoroquinolone, amoxicillin and tetracycline susceptibilities were determined by Etest. PCR followed by DNA sequencing was carried out to determine mutations. The medical records of the patients infected with resistant strains were reviewed to determine the eradication outcome. Metronidazole resistance was encountered in 36.6 % of H. pylori isolates, whereas clarithromycin and fluoroquinolone resistance was observed in 1.2  and 1.9 % of isolates, respectively. All strains tested were susceptible to amoxicillin and tetracycline. Frameshift and nonsense mutations in rdxA and frxA genes resulting in stop codons contributed to metronidazole resistance, which leads to reduced eradication efficacy. A2142G and A2143G mutations of 23S rRNA were identified as causing failure of the eradication therapy. Mutation at either codon 87 or 91 of the gyrA gene was identified in fluoroquinolone-resistant strains. However, the effect of resistance could not be assessed. This study showed that frameshift and nonsense mutations in rdxA or frxA genes and point mutations in the 23S rRNA affected the efficacy of H. pylori eradication therapy.

E-Test or Agar Dilution for Metronidazole Susceptibility Testing of Helicobacter Pylori: Importance of the Prevalence of Metronidazole Resistance

2021 ◽  
Author(s):  
Jinnan Chen ◽  
Yu Huang ◽  
Zhaohui Ding ◽  
Xiao Liang ◽  
Hong Lu
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Resistance Rate ◽  
Test Method ◽  
Major Error ◽  
Metronidazole Resistance ◽  
Agar Dilution ◽  
H Pylori ◽  
High Level ◽  
Level Resistance

Abstract Background: A number of studies have shown that E-test overestimated the presence of Helicobacter pylori (H. pylori) resistance compared to agar dilution.Objective: The purpose of this study was to explore whether E-test could be an alternative for agar dilution to detect the metronidazole susceptibility of H. pylori.Method: E-test and agar dilution were used to assess susceptibility of H. pylori to metronidazole, clarithromycin and levofloxacin in 281 clinical isolates obtained from China where resistance was high. Cohen kappa analysis, McNemar test, essential and categorical agreement analysis were performed for these two methods. Results: Overall, the result of E-test showed similar prevalence of resistance rate to all antibiotics compared with agar dilution. The essential agreement (EA) of E-test method and agar dilution in the evaluation susceptibility of H. pylori to clarithromycin and levofloxacin were moderate, with 89.0% and 79.7% respectively, but only 45.9% for metronidazole. Results showed categorical agreement (CA) between E-test and agar dilution were 100% for both clarithromycin and levofloxacin. As for metronidazole, the CA was 98.7%, no major error was identified, and rate of very major error was 1.8%.Conclusion: E-test can be an alternative method to detect the metronidazole susceptibility of H. pylori in regions where high-level resistance is common.

scholarly journals Antibiotic Resistance Prevalence and Trends in Patients Infected with Helicobacter pylori in the Period 2013–2020: Results of the European Registry on H. pylori Management (Hp-EuReg)

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1058
Author(s):  
Luis Bujanda ◽  
Olga P. Nyssen ◽  
Dino Vaira ◽  
Ilaria M. Saracino ◽  
Giulia Fiorini ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Resistance Rate ◽  
Antimicrobial Susceptibility Testing ◽  
Metronidazole Resistance ◽  
Infected Adult ◽  
H Pylori ◽  
European Registry

Background: Bacterial antibiotic resistance changes over time depending on multiple factors; therefore, it is essential to monitor the susceptibility trends to reduce the resistance impact on the effectiveness of various treatments. Objective: To conduct a time-trend analysis of Helicobacter pylori resistance to antibiotics in Europe. Methods: The international prospective European Registry on Helicobacter pylori Management (Hp-EuReg) collected data on all infected adult patients diagnosed with culture and antimicrobial susceptibility testing positive results that were registered at AEG-REDCap e-CRF until December 2020. Results: Overall, 41,562 patients were included in the Hp-EuReg. Culture and antimicrobial susceptibility testing were performed on gastric biopsies of 3974 (9.5%) patients, of whom 2852 (7%) were naive cases included for analysis. The number of positive cultures decreased by 35% from the period 2013–2016 to 2017–2020. Concerning naïve patients, no antibiotic resistance was found in 48% of the cases. The most frequent resistances were reported against metronidazole (30%), clarithromycin (25%), and levofloxacin (20%), whereas resistances to tetracycline and amoxicillin were below 1%. Dual and triple resistances were found in 13% and 6% of the cases, respectively. A decrease (p < 0.001) in the metronidazole resistance rate was observed between the 2013–2016 (33%) and 2017–2020 (24%) periods. Conclusion: Culture and antimicrobial susceptibility testing for Helicobacter pylori are scarcely performed (<10%) in Europe. In naïve patients, Helicobacter pylori resistance to clarithromycin remained above 15% throughout the period 2013–2020 and resistance to levofloxacin, as well as dual or triple resistances, were high. A progressive decrease in metronidazole resistance was observed.

scholarly journals Epidemiology of the Antibiotic Resistance ofHelicobacter pyloriin Canada

2000 ◽  
Vol 14 (10) ◽  
pp. 879-882 ◽  
Author(s):  
Carlo A Fallone
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Digestive Disease ◽  
Study Group ◽  
Cure Rate ◽  
Antibiotic Resistant ◽  
Treatment Regimens ◽  
Metronidazole Resistance ◽  
American Gastroenterology Association ◽  
H Pylori

BACKGROUND: The rate ofHelicobacter pyloriresistance to antibiotics determines the cure rate of treatment regimens containing such antibiotics. AIMS: To review the literature to determine the rates ofH pyloriresistance to metronidazole and clarithromycin in Canada, and whether these rates vary in different regions of Canada.METHODS: The literature was reviewed extensively for the prevalence of antibiotic-resistantH pyloriin Canada by searching MEDLINE from January 1980 to May 1999, as well as abstracts of the American Gastroenterology Association Digestive Disease Week, Canadian Digestive Disease Week and The EuropeanH pyloriStudy Group Meetings from January 1995 to May 1999.RESULTS: Eleven studies that estimatedH pyloriresistance to metronidazole resistance and nine that estimated resistance to clarithromycin in Canada were identified. Rates of resistance for metronidazole and clarithromycin varied from 11% to 48% and 0% to 12%, respectively. Studies that obtained their estimates using the E-test and those that did not clearly exclude patients who had undergone previous attempts atH pylorieradication had higher estimates of resistance, accounting for this variability in results.CONCLUSIONS: The prevalence of primaryH pyloriresistance in Canada appears to be 18% to 22% for metronidazole and less than 4% for clarithromycin. These rates appear to be consistent across the different regions studied in Canada, but many regions have not been studied.

scholarly journals Analysis of rdxA and Involvement of Additional Genes Encoding NAD(P)H Flavin Oxidoreductase (FrxA) and Ferredoxin-Like Protein (FdxB) in Metronidazole Resistance of Helicobacter pylori

2000 ◽  
Vol 44 (8) ◽  
pp. 2133-2142 ◽  
Author(s):  
Dong-Hyeon Kwon ◽  
Fouad A. K. El-Zaatari ◽  
Mototsugu Kato ◽  
Michael S. Osato ◽  
Rita Reddy ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Resistant Strain ◽  
Resistance Mechanisms ◽  
Sensitive Strain ◽  
Metronidazole Resistance ◽  
Genes Encoding ◽  
Resistant Strains ◽  
Flavin Oxidoreductase ◽  
H Pylori

ABSTRACT Metronidazole (Mtz) is a critical ingredient of modern multidrug therapies for Helicobacter pylori infection. Mtz resistance reduces the effectiveness of these combinations. Although null mutations in a rdxA gene that encodes oxygen-insensitive NAD(P)H nitroreductase was reported in Mtz-resistant H. pylori, an intact rdxA gene has also been reported in Mtz-resistant H. pylori, suggesting that additional Mtz resistance mechanisms exist in H. pylori. We explored the nature of Mtz resistance among 544 clinical H. pyloriisolates to clarify the role of rdxA inactivation in Mtz resistance and to identify another gene(s) responsible for Mtz resistance in H. pylori. Mtz resistance was present in 33% (181 of 544) of the clinical isolates. There was marked heterogeneity of resistance, with Mtz MICs ranging from 8 to ≥256 μg/ml.rdxA inactivation resulted in Mtz MICs of up to 32 μg/ml for 6 Mtz-sensitive H. pylori strains and 128 μg/ml for one Mtz-sensitive strain. Single or dual (with rdxA) inactivation of genes that encode ferredoxin-like protein (designatedfdxB) and NAD(P)H flavin oxidoreductase (frxA) also increased the MICs of Mtz for sensitive and resistant strains with low to moderate levels of Mtz resistance. fdxB inactivation resulted in a lower level of resistance than that from rdxAinactivation, whereas frxA inactivation resulted in MICs similar to those seen with rdxA inactivation. Further evidence for involvement of the frxA gene in Mtz resistance included the finding of a naturally inactivated frxA but an intact rdxA in an Mtz-resistant strain, complementation of Mtz sensitivity from an Mtz-sensitive strain to an Mtz-resistant strain or vice versa by use of naturally inactivated or functionalfrxA genes, respectively, and transformation of an Mtz-resistant Escherichia coli strain to an Mtz sensitive strain by a naturally functional frxA gene but not an inactivated frxA gene. These results are consistent with the hypothesis that null mutations in fdxB,frxA, or rdxA may be involved in Mtz resistance.

scholarly journals ANTIBIOTIC RESISTANCE SURVEILLANCE OF HELICOBACTER PYLORI AT THE BIOBÍO REGION (CHILE) IN A DECADE

2019 ◽  
Vol 56 (4) ◽  
pp. 361-366
Author(s):  
Cristian PARRA-SEPÚLVEDA ◽  
José S MERINO ◽  
Katia SÁEZ-CARRILLO ◽  
Carlos GONZÁLEZ ◽  
Apolinaria GARCÍA-CANCINO
Keyword(s):  
Health Care ◽  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Blood Cells ◽  
Eradication Therapy ◽  
Clarithromycin Resistance ◽  
Resistant Strains ◽  
H Pylori ◽  
Horse Red Blood Cells ◽  
Co2 Atmosphere

ABSTRACT BACKGROUND: Helicobacter pylori infection in Chile remains as a public and private health-care system’s challenge, with a prevalence of the infection over 70%. Nowadays, antibiotic treatment of the infection is mandatory to prevent the arising of severe associated diseases but failures in the eradication therapy mainly due to clarithromycin resistance has been observed worldwide and first line eradication therapy seems to be not effective anymore in several geographical areas. Thus, health-care systems are committed to maintain an epidemiological surveillance upon the evolution of the antibiotic resistance of this priority 2 pathogen. OBJECTIVE: This work reports a 10 years surveillance of the primary antibiotic resistance of H. pylori clinical isolates at the Biobío region-Chile, and the evolution of resistance toward amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline among the species. METHODS: H. pylori strains were investigated during the periods 2005-2007 (1435 patients analysed) and 2015-2017 (220 patients analysed) by inoculating a saline homogenate biopsy onto the surface of Columbia agar (Oxoid, Basingstoke, UK) - supplemented with 7% horse red blood cells plus DENT inhibitor (Oxoid, Basingstoke, UK) - following by incubation at 37ºC under 10% CO2 atmosphere for five days. Antibiotic resistance pattern of the isolates was assessed using the disk diffusion test in Müeller-Hinton agar supplemented with 7% horse red blood cells followed by incubation for further three days under 10% CO2 atmosphere. Statistical analysis was done using the SPSS v22 software and P values <0.05 were considered statistically significant. RESULTS: A total of 41% of 1435 patients were detected to be infected with H. pylori by bacteriological culture in 2005-2007 period, meanwhile 32.7% from 220 patients were also infected in 2015-2017 period. The clinical isolates of H. pylori are mostly susceptible to amoxicillin and tetracycline (both over 98% of strains), but less susceptible to levofloxacin in both periods analysed (over 79% of the strains). On the other hand, metronidazole continuous showing the highest score of resistant isolates (over 40% of resistant strains), although an 18% fewer resistant strains were observed in 2015-2017 period. Clarithromycin, the key antibiotic in eradication therapies, has an increased frequency of resistant strain isolated in the decade (22.5% in 2005-2007 and 29.2% in 2015-2017). Multidrug resistant strains (two, three and four antibiotics) were also detected in both periods with the highest scores for simultaneous resistance to clarithromycin-metronidazole (18%) and clarithromycin-metronidazole-levofloxacin (12.5%) resistant strains. According to gender, the isolates resistant to amoxicillin, clarithromycin and metronidazole were more frequent in female, with a specific increment in amoxicillin and clarithromycin resistance. CONCLUSION: The frequency of clarithromycin resistance (29.2%) detected in 2015-2017 suggests that conventional triple therapy is no longer effective in this region.

scholarly journals Treatment of Helicobacter pylori infections in the light of the increase of antibiotic resistance

2018 ◽  
Vol 72 ◽  
pp. 143-158
Author(s):  
Eliza Mnich ◽  
Jakub Ibran ◽  
Magdalena Chmiela
Keyword(s):  
Fatty Acids ◽  
Ascorbic Acid ◽  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Eradication Therapy ◽  
The World ◽  
Potential Alternative ◽  
Resistant Strains ◽  
Treatment Mechanisms ◽  
H Pylori

The aim of this study was to present the risks associated with the occurrence of Helicobacter pylori (H. pylori) infection in humans and the problems related to eradication procedures with the use of antibiotic treatment. The content provides an overview of the available methods of infection diagnosis and recommended therapeutic schemes as well as potential alternative schedules of treatment. Mechanisms of H. pylori resistance to commonly used antibiotics including the mutations in the genome leading to resistance and the incidence of resistant strains in the world has been described. Finally, we introduced substances with some potential in eradication therapy, including probiotics, plant formulations as well as polyunsaturated fatty acids and ascorbic acid.

scholarly journals Microarray-Based Detection and Clinical Evaluation for Helicobacter pylori Resistance to Clarithromycin or Levofloxacin and the Genotype of CYP2C19 in 1083 Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yi Song ◽  
Fengna Dou ◽  
Zhe Zhou ◽  
Ningmin Yang ◽  
Jing Zhong ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Limit Of Detection ◽  
Eradication Therapy ◽  
Gastric Biopsy ◽  
Individual Therapy ◽  
23S Rrna ◽  
Antibiotic Administration ◽  
Cyp2c19 Polymorphism ◽  
H Pylori

Background. Helicobacter pylori (H. pylori) is one of the most frequent and persistent bacterial infections that affect nearly half of the world’s population. Antibiotic resistance is a constantly evolving process and local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy. The aim of this study was to establish a microarray-based detection to identify H. pylori infection, clarithromycin and levofloxacin susceptibility, and CYP2C19 genetic polymorphism and guide to potential choice of proton pump inhibitor (PPI), antibiotic administration for tailored H. pylori eradication therapy. Methods. By analyzing the sequence of human genomic CYP2C19⁎2 and CYP2C19⁎3 and mutations within the 23S rRNA and gyrA gene regions conferring clarithromycin and levofloxacin resistance, respectively, we developed a microarray for individual therapy detection of H. pylori infection. Plasmids were established as positive or limit of detection (LOD) reference materials. The specificity and sensitivity of the microarray had been performed. And a total of 1083 gastric biopsy samples were tested and the Kappa value had been calculated between the array and Sanger sequencing. We also analyzed the resistance to clarithromycin and levofloxacin in China, as well as the CYP2C19 polymorphisms. Results. The LOD of detecting H. pylori was 103 CFU/mL and human genome DNA was 2 ng/μL. The detection results of 1083 gastric biopsy samples showed that 691 (63.80%) were H. pylori positive, of which 266 (38.49%) were resistant to clarithromycin, 192 (27.79%) were resistant to levofloxacin, and 61 (8.83%) were resistant to both of them. For the type of CYP2C19 polymorphism, 412 (38.04%) were homozygous fast type (HomEM), 574 (53%) were heterozygous EM (HetEM), and 97 (8.96%) were poor metabolizer (PM). Conclusions. The proposed microarray-based detection has high specificity, sensitivity, and reproducibility for detecting the resistance of clarithromycin or levofloxacin as well as CYP2C19 polymorphism, which may help to improve the clinical eradication rate of H. pylori.

scholarly journals Effect of Acid-Suppressive Therapy onHelicobactor pyloriProduction of Interleukin-8 in Gastric Mucosa

2000 ◽  
Vol 14 (4) ◽  
pp. 277-282 ◽  
Author(s):  
Masahiro Yoshinaga ◽  
Akira Ohtani ◽  
Satoru Tsuruta ◽  
Tetsuya Kato ◽  
Eishi Higashi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Reflux Esophagitis ◽  
Serum Gastrin ◽  
Histological Finding ◽  
Gastric Biopsy ◽  
Suppressive Therapy ◽  
Biopsy Specimens ◽  
Gastric Corpus ◽  
Colonization Density ◽  
H Pylori

BACKGROUND: Recent studies have shown that acid-suppressive therapy increases the severity ofHelicobacter pylori- associated gastritis in the corpus.PURPOSE: To evaluate interleukin (IL)-8 production in the gastric corpus mucosa before and during acid-suppressive therapy inH pylori-infected patients.PATIENTS AND METHODS: Ten patients with reflux esophagitis (fiveH pylori-positive and fiveH pylori-negative) were treated with omeprazole 20 mg. Serum gastrin concentrations,H pyloricolonization density and mucosal IL-8 levels in the corpus were investigated at entry and two weeks after starting therapy. IL-8 levels were measured by ELISA. The organism density was determined, and scored according to area occupied by the bacterial colonies. The presence ofH pyloriwas assessed by rapid urease testing and histological finding of gastric biopsy specimens.RESULTS: InH pylori-positive patients, concentrations of IL-8 during therapy significantly exceeded those before therapy (36.2±6.8 versus 18.3±3.8 pg/mg protein; P<0.05) without alteringH pyloridensity. InH pylori-negative patients, IL-8 levels were similar before and during therapy (6.1±2.7 versus 6.3±3.0 pg/mg protein). Concentrations of gastrin during therapy were significantly higher than those before therapy in all patients.CONCLUSIONS: The results suggest that acid suppression increases mucosal IL-8 levels inH pylori-infected patients with reflux esophagitis.

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