scholarly journals Phenotypic and Molecular Antimicrobial Susceptibility of Helicobacter pylori

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Derrick Chen ◽  
Scott A. Cunningham ◽  
Nicolynn C. Cole ◽  
Peggy C. Kohner ◽  
Jayawant N. Mandrekar ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Point Mutations ◽  
The United States ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene ◽  
H Pylori

ABSTRACT Failure to eradicate Helicobacter pylori infection is often a result of antimicrobial resistance, which for clarithromycin is typically mediated by specific point mutations in the 23S rRNA gene. The purpose of this study was to define current patterns of antimicrobial susceptibility in H. pylori isolates derived primarily from the United States and to survey them for the presence of point mutations in the 23S rRNA gene and assess the ability of these mutations to predict phenotypic clarithromycin susceptibility. Antimicrobial susceptibility testing was performed using agar dilution on 413 H. pylori isolates submitted to Mayo Medical Laboratories for susceptibility testing. For a subset of these isolates, a 150-bp segment of the 23S rRNA gene was sequenced. A total of 1,970 MICs were reported over the 4-year study period. The rate of clarithromycin resistance was high (70.4%), and elevated MICs were frequently observed for metronidazole (82.4% of isolates had an MIC of >8 μg/ml) and ciprofloxacin (53.5% of isolates had an MIC of >1 μg/ml). A total of 111 archived H. pylori isolates underwent 23S rRNA gene sequencing; we found 95% concordance between genotypes and phenotypes (P = 0.9802). Resistance to clarithromycin was most commonly due to an A2143G mutation (82%), followed by A2142G (14%) and A2142C (4%) mutations. Clinical H. pylori isolates derived primarily from the United States demonstrated a high rate of clarithromycin resistance and elevated metronidazole and ciprofloxacin MICs. The relative distribution of point mutations at positions 2143 and 2142 in the 23S rRNA gene in clarithromycin-resistant H. pylori was similar to that reported from other parts of the world; these mutations predict phenotypic resistance to clarithromycin.

scholarly journals Antimicrobial susceptibility and clarithromycin resistance patterns of Helicobacter pylori clinical isolates in Vietnam

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 671 ◽  
Author(s):  
Camelia Quek ◽  
Son T. Pham ◽  
Kieu T. Tran ◽  
Binh T. Pham ◽  
Loc V. Huynh ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
Resistance Patterns ◽  
23S Rrna Gene ◽  
H Pylori

Helicobacter pylori is a gastric pathogen that causes several gastroduodenal disorders such as peptic ulcer disease and gastric cancer.  Eradication efforts of H. pylori are often hampered by antimicrobial resistance in many countries, including Vietnam.  Here, the study aimed to investigate the occurrence of antimicrobial resistance among H. pylori clinical isolates across 13 hospitals in Vietnam.  The study further evaluated the clarithromycin resistance patterns of H. pylori strains.  In order to address the study interests, antimicrobial susceptibility testing, epsilometer test and PCR-based sequencing were performed on a total of 193 strains isolated from patients, including 136 children (3–15 years of age) and 57 adults (19–69 years of age).  Antimicrobial susceptibility testing showed that the overall resistance to amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline was 10.4%, 85.5%, 24.4%, 37.8%, and 23.8% respectively.  The distribution of minimum inhibitory concentrations (MICs) of clarithromycin-resistant strains was 85.5% with MIC >0.5 μg/mL.  The majority of the clarithromycin resistant isolates (135 of 165 subjects) have MICs ranging from 2 μg/mL to 16 μg/mL.  Furthermore, sequencing detection of mutations in 23S rRNA gene revealed that strains resistant and susceptible to clarithromycin contained both A2143G and T2182C mutations.  Of all isolates, eight clarithromycin-resistant isolates (MIC >0.5 μg/mL) had no mutations in the 23S rRNA gene.  Collectively, these results demonstrated that a proportion of clarithromycin-resistant H. pylori strains, which are not related to the 23S rRNA gene mutations, could be potentially related to other mechanisms such as the presence of an efflux pump or polymorphisms in the CYP2C19 gene.  Therefore, the present study suggests that providing susceptibility testing prior to treatment or alternative screening strategies for antimicrobial resistance is important for future clinical practice.  Further studies on clinical guidelines and treatment efficacy are pivotal for successful eradication of H. pylori infection.

scholarly journals 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

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Jina Vazirzadeh ◽  
Jamal Falahi ◽  
Sharareh Moghim ◽  
Tahmineh Narimani ◽  
Rahmatollah Rafiei ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
In Situ Hybridization ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
Genotypic Analysis ◽  
23S Rrna Gene ◽  
H Pylori

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.

scholarly journals PCR-RFLP detection of point mutations A2143G and A2142G in 23S rRNA gene conferring resistance to clarithromycin in Helicobacter pylori strains.

2014 ◽  
Vol 61 (2) ◽  
Author(s):  
Karolina Klesiewicz ◽  
Paweł Nowak ◽  
Elżbieta Karczewska ◽  
Iwona Skiba ◽  
Izabela Wojtas-Bonior ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
Rflp Analysis ◽  
23S Rrna ◽  
Rrna Gene ◽  
Efficient Management ◽  
Clarithromycin Resistance ◽  
Pcr Rflp ◽  
23S Rrna Gene ◽  
H Pylori

The occurrence of clarithromycin resistance among Helicobacter pylori strains is a major cause of the treatment failure. Resistance to this drug is conferred by point mutations in 23S rRNA gene and the most prevalent mutations are A2143G and A2142G. The aim of the study was to evaluate the occurrence of A2143G and A2142G mutations in a group of H. pylori strains resistant to clarithromycin. The study included 21 clarithromycin-resistant H. pylori strains collected between 2006 and 2009 in southern Poland. Resistance to clarithromycin was quantitatively tested with the E-test to determine the minimal inhibitory concentration (MIC value). The point mutations of H. pylori isolates were detected by PCR followed by RFLP analysis. The MIC values for clarithromycin for the analyzed strains ranged from 1.5 mg/L to 64 mg/L. Nine H. pylori strains exhibited A2143G mutation and A2142G mutation was found in 9 isolates as well. The results of RFLP analysis of 3 clarithromycin-resistant strains were negative for both mutations. The average MIC values for A2143G and A2142G mutants were 6 and 30 mg/L, respectively. Frequencies of A2143G and A2142G mutations were the same in all isolates tested. Strains with A2143G mutation exhibited lower MIC values than A2142G mutants. Application of PCR-RFLP method for detection of clarithromycin resistance allows for better and more efficient management of H. pylori infections.

Helicobacter pylori 23S rRNA gene A2142G, A2143G, T2182C, and C2195T mutations associated with clarithromycin resistance detected in Sudanese patients

2020 ◽  
Author(s):  
Aalaa Mahgoub Albasha ◽  
Maram M. Alnosh ◽  
Esraa Hassan Osman ◽  
Duha M Zeinalabdin ◽  
Amira A M Fadl ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Specific Pcr ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene ◽  
Allele Specific ◽  
H Pylori ◽  
Allele Specific Pcr

Abstract Background: Clarithromycin resistant Helicobacter pylori (H. pylori) strains represent a worldwide health problem. These stains are usually carrying mutations within the 23S rRNA gene associated with clarithromycin resistance. This study aimed to detect H. pylori and clarithromycin resistant associated mutations from Sudanese patients with gastritis symptoms.Materials and Methods: Two hundred and eighty-eight gastric biopsies were collected using gastrointestinal endoscopy from patients with gastritis symptoms in different hospitals in Khartoum state. H. pylori was detected by PCR using primers targeting 16S rRNA and 23S rRNA. Then allele-specific PCR and DNA sequencing were used to screen for the presence of A2142G and A2143G point mutations.Results: Out of 288 samples, H. pylori was detected in 97 (33.7%) sample. Allele-specific PCR detected the variant A2142G in 9/97 (9.3%) sample, while A2143G mutation was not found in any sample. The DNA sequencing revealed the presence of mutations associated with clarithromycin-resistance in 48% (12/25) of samples; the A2142G was present in one sample, A2143G in 5 samples, T2182C in 4 samples, and C2195T in 3 samples. There was no association of 23S rRNA gene point mutations with gender, age group and geographical distribution of patients.Conclusion: This study revealed a high frequency (48%) of mutations associated with clarithromycin resistance using DNA sequencing of the 23S rRNA gene's V domain. This information should be taken into consideration before choosing optimal therapy for H. pylori eradication.

scholarly journals Impact of Clarithromycin Resistance on Eradication of Helicobacter pylori in Infected Adults

2005 ◽  
Vol 49 (4) ◽  
pp. 1600-1603 ◽  
Author(s):  
Jong Hwa Lee ◽  
Ji-Hyun Shin ◽  
Im Hwan Roe ◽  
Seung Ghyu Sohn ◽  
Jung Hun Lee ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Drug Therapy ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Gastric Biopsy ◽  
Antimicrobial Susceptibility Testing ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene

ABSTRACT The outcome of Helicobacter pylori infection was analyzed in 114 dyspeptic patients treated with triple-drug therapy including clarithromycin. Clarithromycin resistance (in 20.2% of our isolates) was mainly caused by an A2142G mutation in the 23S rRNA gene of H. pylori. H. pylori eradication was obtained in all patients with clarithromycin-susceptible isolates but not in any patients with clarithromycin-resistant isolates (P = 0.0001). Therefore, it would be useful to conduct H. pylori antimicrobial susceptibility testing of the first gastric biopsy culture before choosing the first three drugs for therapy of infected patients.

scholarly journals Helicobacter pylori 23S rRNA gene A2142G, A2143G, T2182C, and C2195T mutations associated with clarithromycin resistance detected in Sudanese patients

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Aalaa Mahgoub Albasha ◽  
Maram M. Elnosh ◽  
Esraa Hassan Osman ◽  
Duha M. Zeinalabdin ◽  
Amira A. M. Fadl ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Specific Pcr ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene ◽  
Allele Specific ◽  
H Pylori ◽  
Allele Specific Pcr

Abstract Background Clarithromycin resistant Helicobacter pylori (H. pylori) strains represent a worldwide health problem. These stains are usually carrying mutations within the 23S rRNA gene associated with clarithromycin resistance. This study aimed to detect H. pylori and clarithromycin resistant associated mutations from Sudanese patients with gastritis symptoms. Materials and methods Two hundred and eighty-eight gastric biopsies were collected using gastrointestinal endoscopy from patients with gastritis symptoms in different hospitals in Khartoum state. H. pylori was detected by PCR using primer targeting 16S rRNA. Then allele-specific PCR and DNA sequencing were used to screen for the presence of A2142G and A2143G point mutations. Results Out of 288 samples, H. pylori was detected in 88 (~ 30.6%) samples by 16 s RNA. Allele-specific PCR detected the variant A2142G in 9/53 (~ 17%) sample, while A2143G mutation was not found in any sample. The DNA sequencing revealed the presence of mutations associated with clarithromycin-resistance in 36% (9/25) of samples; the A2142G was present in one sample, A2143G in 5 samples and T2182C in 4 samples. Additionally, another point mutation (C2195T) was detected in 3 samples. There was no association of 23S rRNA gene point mutations with gender, age group, and patients’ geographical distribution. Conclusion This study revealed a high frequency (36%) of mutations associated with clarithromycin resistance using DNA sequencing of the 23S rRNA gene’s V domain. This information should be taken into consideration to avoid eradication therapy failing.

scholarly journals Trends towards Lower Antimicrobial Susceptibility and Characterization of Acquired Resistance among Clinical Isolates of Brachyspira hyodysenteriae in Spain

2011 ◽  
Vol 55 (7) ◽  
pp. 3330-3337 ◽  
Author(s):  
Álvaro Hidalgo ◽  
Ana Carvajal ◽  
Birte Vester ◽  
Märit Pringle ◽  
Germán Naharro ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Molecular Mechanisms ◽  
Tandem Repeats ◽  
Point Mutations ◽  
Clinical Isolates ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Brachyspira Hyodysenteriae ◽  
23S Rrna Gene

ABSTRACTThe antimicrobial susceptibility of clinical isolates ofBrachyspira hyodysenteriaein Spain was monitored, and the underlying molecular mechanisms of resistance were investigated. MICs of tylosin, tiamulin, valnemulin, lincomycin, and tylvalosin were determined for 87B. hyodysenteriaeisolates recovered from 2008 to 2009 by broth dilution. Domain V of the 23S rRNA gene and the ribosomal protein L3 gene were sequenced in 20 isolates for which the tiamulin MIC was ≥4 μg/ml, presenting decreased susceptibility, and in 18 tiamulin-susceptible isolates (MIC ≤ 0.125 μg/ml), and all isolates were typed by multiple-locus variable-number tandem repeats analysis. A comparison with antimicrobial susceptibility data from 2000 to 2007 showed an increase in pleuromutilin resistance over time, doubling the number of isolates with decreased susceptibility to tiamulin. No alteration in susceptibility was detected for lincomycin, and the MIC of tylosin remained high (MIC50> 128 μg/ml). The decreased susceptibility to tylosin and lincomycin can be explained by mutations at position A2058 of the 23S rRNA gene (Escherichia colinumbering). A2058T was the predominant mutation, but A2058G also was found together with a change of the neighboring base pair at positions 2057 to 2611. The role of additional point mutations in the vicinity of the peptidyl transferase center and mutations in the L3 at amino acids 148 and 149 and their possible involvement in antimicrobial susceptibility are considered. An association between G2032A and high levels of tiamulin and lincomycin MICs was found, suggesting an increasing importance of this mutation in antimicrobial resistance of clinical isolates ofB. hyodysenteriae.

STUDY ON POINT MUTATIONS AT POSITIONS 2132 AND 2143 IN 23S RRNA GENE OF HELICOBACTER PYLORI AMONG PATIENTS WITH CHRONIC GASTRITIS

2016 ◽  
pp. 12-20
Author(s):  
Thi Minh Thi Ha ◽  
Van Huy Tran ◽  
Viet Nhan Nguyen ◽  
Thanh Hoa Nguyen ◽  
Phan Tuong Quynh Le
Keyword(s):  
Helicobacter Pylori ◽  
Chronic Gastritis ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
Pcr Rflp ◽  
23S Rrna Gene ◽  
History Of ◽  
H Pylori

Background: Clarithromycin resistance in Helicobacter pylori has been found to be associated with point mutations at positions 2142 and 2143 in 23SrRNA gene. The aims of this study were: (1) to determine the rates of point mutations A2143G, A2142G and A2142C in 23SrRNA gene of H. pylori among patients with chronic gastritis by PCR-RFLP technique; and (2) to assessthe association between these mutations and some clinical, endoscopic and histopathological characteristics of chronic gastritis. Patients and methods: two hundreds and twenty six patients with H. pylori-positive chronic gastritis were determined A2143G, A2142G and A2142C mutations by PCR-RFLP technique with DNA extracted from endoscopic biopsy specimens of gastric mucosa. Results: The rate of point mutations at positions 2142 and 2143 in 23S rRNA gene of H. pylori was 35.4% in total, the A2143G and A2142G mutationsaccounted for 92.5% and 7.5% of all point mutations, respectively. No A2142C mutation was found. These mutations were not associated with age, gender,distribution of gastritis, and the presence of atrophic gastritis. The rate of A2143G mutation in groups with and without a history of clarithromycin treatment were 44.9% and 24.8%, respectively (p = 0,0065). The A2142G mutation was associated with intestinal metaplasia and/or dysplasia. Conclusion: The point mutations at positions 2142 and 2143 in 23S rRNA gene were found at a high rate in H. pylori strains amongpatients with chronic gastritis, with the absolute predominance of A2143G mutation. The A2143G mutation was associated with a history of clarithromycin treatment. Key words: 23S rRNA gene, Helicobacter pylori, A2143G, A2142G, A2142C mutation, clarithromycin resistance, chronic gastritis.

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