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 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 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 Genotypic Characterization of Clarithromycin-Resistant and -Susceptible Helicobacter pylori Strains from the Same Patient Demonstrates Existence of Two Unrelated Isolates

1998 ◽  
Vol 36 (9) ◽  
pp. 2730-2731 ◽  
Author(s):  
Ge Wang ◽  
Qin Jiang ◽  
Diane E. Taylor
Keyword(s):  
Helicobacter Pylori ◽  
Gel Electrophoresis ◽  
Genomic Dna ◽  
Pulsed Field Gel Electrophoresis ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene ◽  
Mode Of Development

Clarithromycin-susceptible and clarithromycin-resistantHelicobacter pylori isolates from the same patient were investigated for the mode of development and mechanism of clarithromycin resistance. The clarithromycin-resistant strain UA1182 harbors homozygous A-to-G mutations at position 2143 in both copies of the 23S rRNA gene and has a phenotype of resistance to clarithromycin and clindamycin but no significant resistance to streptogramin B. Pulsed-field gel electrophoresis patterns of NruI- andNotI-digested genomic DNA from the Clas and Clar isolates demonstrated that they are genetically distinct, suggesting that the development of clarithromycin resistance is not from the mutation of the existing Clas strain but from a completely new strain.

scholarly journals Mutations in the 23S rRNA gene are associated with clarithromycin resistance in Helicobacter pylori isolates in Brazil

2003 ◽  
Vol 2 (1) ◽  
Author(s):  
Marcelo L Ribeiro ◽  
Lea Vitiello ◽  
Maira CB Miranda ◽  
Yune HB Benvengo ◽  
Anita PO Godoy ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene

scholarly journals New Site of Modification of 23S rRNA Associated with Clarithromycin Resistance of Helicobacter pylori Clinical Isolates

2002 ◽  
Vol 46 (12) ◽  
pp. 3765-3769 ◽  
Author(s):  
Carla Fontana ◽  
Marco Favaro ◽  
Silvia Minelli ◽  
Anna Angela Criscuolo ◽  
Antonio Pietroiusti ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
23S Rrna ◽  
Dilution Method ◽  
Rrna Gene ◽  
Functional Sites ◽  
Biopsy Specimens ◽  
Clarithromycin Resistance ◽  
Pcr Product ◽  
23S Rrna Gene ◽  
H Pylori

ABSTRACT Resistance of Helicobacter pylori to clarithromycin occurs with a prevalence ranging from 0 to 15%. This has an important clinical impact on dual and triple therapies, in which clarithromycin seems to be the better choice to achieve H. pylori eradication. In order to evaluate the possibility of new mechanisms of clarithromycin resistance, a PCR assay that amplified a portion of 23S rRNA from H. pylori isolates was used. Gastric tissue biopsy specimens from 230 consecutive patients were cultured for H. pylori isolation. Eighty-six gastric biopsy specimens yielded H. pylori-positive results, and among these 12 isolates were clarithromycin resistant. The latter were studied to detect mutations in the 23S rRNA gene. Sequence analysis of the 1,143-bp PCR product (portion of the 23S rRNA gene) did not reveal mutation such as that described at position 2142 to 2143. On the contrary, our findings show, for seven isolates, a T-to-C transition at position 2717. This mutation conferred a low level of resistance, equivalent to the MIC for the isolates, selected using the E-test as well as using the agar dilution method: 1 μg/ml. Moreover, T2717C transition is located in a highly conserved region of the 23S RNA associated with functional sites: domain VI. This fact has a strong effect on the secondary structure of the 23S RNA and on its interaction with macrolide. Mutation at position 2717 also generated an HhaI restriction site; therefore, restriction analysis of the PCR product also permits a rapid detection of resistant isolates.

Prediction of Helicobacter Pylori Clarithromycin Resistance by Detection of Point Mutations in 23S rRNA Gene

2018 ◽  
Vol 27 (3) ◽  
pp. 13-20
Author(s):  
Hayam E. Rashed ◽  
Marwa A. Mansour ◽  
Mostafa A. Soltan ◽  
Tarek I. Zahir ◽  
Yasmin A. Fahmy
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene
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