scholarly journals Comparable genetic alteration profiles between gastric cancers with current and past Helicobacter pylori infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sho Tsuyuki ◽  
Hideyuki Takeshima ◽  
Shigeki Sekine ◽  
Yukinori Yamagata ◽  
Takayuki Ando ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gene Amplification ◽  
Point Mutations ◽  
Genetic Alterations ◽  
Past Infection ◽  
Gastric Cancers ◽  
Target Sequencing ◽  
Oncogene Activation ◽  
Current Infection ◽  
H Pylori

AbstractGastric cancers can develop even after Helicobacter pylori (H. pylori) eradication in 0.2–2.9% cases per year. Since H. pylori is reported to directly activate or inactivate cancer-related pathways, molecular profiles of gastric cancers with current and past H. pylori infection may be different. Here, we aimed to analyze whether profiles of point mutation and gene amplification are different between the two groups. Current or past infection by H. pylori was determined by positive or negative amplification of H. pylori jhpr3 gene by PCR, and past infection was established by the presence of endoscopic atrophy. Among the 90 gastric cancers analyzed, 55 were with current infection, and 35 were with past infection. Target sequencing of 46 cancer-related genes revealed that 47 gastric cancers had 68 point mutations of 15 different genes, such as TP53 (36%), KRAS (4%), and PIK3CA (4%) and that gene amplification was present for ERBB2, KRAS, PIK3CA, and MET among the 26 genes assessed for copy number alterations. Gastric cancers with current and past infection had similar frequencies of TP53 mutations (38% and 31%, respectively; p = 0.652) and oncogene activation (20% and 29%, respectively; p = 0.444). Gastric cancers with current and past infection had comparable profiles of genetic alterations.

scholarly journals Genomic Analysis of Antimicrobial Resistance Genotype-to-Phenotype Agreement in Helicobacter pylori

2020 ◽  
Vol 9 (1) ◽  
pp. 2
Author(s):  
Tal Domanovich-Asor ◽  
Yair Motro ◽  
Boris Khalfin ◽  
Hillary A. Craddock ◽  
Avi Peretz ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Resistance ◽  
Point Mutations ◽  
Genomic Analysis ◽  
23S Rrna ◽  
Phenotype Correlation ◽  
Bioinformatics Pipeline ◽  
Phenotypic Resistance ◽  
Commercial Kits ◽  
H Pylori

Antimicrobial resistance (AMR) in Helicobacter pylori is increasing and can result in treatment failure and inappropriate antibiotic usage. This study used whole genome sequencing (WGS) to comprehensively analyze the H. pylori resistome and phylogeny in order to characterize Israeli H. pylori. Israeli H. pylori isolates (n = 48) underwent antimicrobial susceptibility testing (AST) against five antimicrobials and WGS analysis. Literature review identified 111 mutations reported to correlate with phenotypic resistance to these antimicrobials. Analysis was conducted via our in-house bioinformatics pipeline targeting point mutations in the relevant genes (pbp1A, 23S rRNA, gyrA, rdxA, frxA, and rpoB) in order to assess genotype-to-phenotype correlation. Resistance rates of study isolates were as follows: clarithromycin 54%, metronidazole 31%, amoxicillin 10%, rifampicin 4%, and levofloxacin 2%. Genotype-to-phenotype correlation was inconsistent; for every analyzed gene at least one phenotypically susceptible isolate was found to have a mutation previously associated with resistance. This was also observed regarding mutations commonly used in commercial kits to diagnose AMR in H. pylori cases. Furthermore, 11 novel point mutations associated with a resistant phenotype were detected. Analysis of a unique set of H. pylori isolates demonstrates that inferring resistance phenotypes from WGS in H. pylori remains challenging and should be optimized further.

scholarly journals Helicobacter pylori Eradication According to Sequencing-Based 23S Ribosomal RNA Point Mutation Associated with Clarithromycin Resistance

2019 ◽  
Vol 9 (1) ◽  
pp. 54 ◽  
Author(s):  
Seung In Seo ◽  
Byoung Joo Do ◽  
Jin Gu Kang ◽  
Hyoung Su Kim ◽  
Myoung Kuk Jang ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutation ◽  
Ribosomal Rna ◽  
Eradication Rate ◽  
Point Mutations ◽  
Clarithromycin Resistance ◽  
Clinically Significant ◽  
H Pylori ◽  
23S Ribosomal Rna ◽  
Significant Point

Background/Aims: Clarithromycin resistance in Helicobacter pylori is associated with point mutations in the 23S ribosomal RNA (rRNA) gene. We investigated the point mutations in the 23S rRNA genes of patients with clarithromycin-resistant H. pylori and compared the H. pylori eradication rates based on the point mutations. Methods: A total of 431 adult patients with H. pylori infection were recruited in Kangdong Sacred Heart Hospital in 2017 and 2018. Patients who did not have point mutations related to clarithromycin resistance and/or had clinically insignificant point mutations were treated with PAC (proton pump inhibitor, amoxicillin, clarithromycin) for seven days, while patients with clinically significant point mutations were treated with PAM (proton pump inhibitor, amoxicillin, metronidazole) for seven days. H. pylori eradication rates were compared. Results: Sequencing-based detection of point mutations identified four mutations that were considered clinically significant (A2142G, A2142C, A2143G, A2143C). The clarithromycin resistance rate was 21.3% in the overall group of patients. A2143G was the most clinically significant point mutation (84/431, 19.5%), while T2182C was the most clinically insignificant point mutation (283/431, 65.7%). The overall H. pylori eradication rate was 83.7%, and the seven-day PAM-treated clarithromycin-resistance group showed a significantly lower eradication rate than the seven-day PAC-treated nonresistance group (ITT; 55.4% (51/92) vs. 74.3% (252/339), p = 0.001, PP; 66.2% (51/77) vs. 88.4% (252/285), p = 0.0001). Conclusions: There were significantly lower eradication rates in the patients with clarithromycin-resistant H. pylori when treated with PAM for seven days. A future study comparing treatment regimens in clarithromycin-resistant H. pylori-infected patients may be necessary.

scholarly journals Macrolide resistance in Helicobacter pylori: rapid detection of point mutations and assays of macrolide binding to ribosomes.

1997 ◽  
Vol 41 (12) ◽  
pp. 2724-2728 ◽  
Author(s):  
A Occhialini ◽  
M Urdaci ◽  
F Doucet-Populaire ◽  
C M Bébéar ◽  
H Lamouliatte ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
Restriction Enzymes ◽  
The United States ◽  
Drug Binding ◽  
Macrolide Resistance ◽  
Rrna Genes ◽  
23S Rrna ◽  
Dependent Manner ◽  
H Pylori

Resistance of Helicobacter pylori to macrolides is a major cause of failure of eradication therapies. Single base substitutions in the H. pylori 23S rRNA genes have been associated with macrolide resistance in the United States. Our goal was to extend this work to European strains, to determine the consequence of this mutation on erythromycin binding to H. pylori ribosomes, and to find a quick method to detect the mutation. Seven pairs of H. pylori strains were used, the parent strain being naturally susceptible to macrolides and the second strain having acquired an in vivo resistance during a treatment regimen that included clarithromycin. The identity of the strains was confirmed by random amplified polymorphic DNA testing with two different primers, indicating that resistance was the result of the selection of variants of the infecting strain. All resistant strains were found to have point mutations at position 2143 (three cases) or 2144 (four cases) but never on the opposite DNA fragment of domain V of the 23S rRNA gene. The mutation was A-->G in all cases except one (A-->C) at position 2143. Using BsaI and BbsI restriction enzymes on the amplified products, we confirmed the mutations of A-->G at positions 2144 and 2143, respectively. Macrolide binding was tested on purified ribosomes isolated from four pairs of strains with [14C]erythromycin. Erythromycin binding increased in a dose-dependent manner for the susceptible strain but not for the resistant one. In conclusion we suggest that the limited disruption of the peptidyltransferase loop conformation, caused by a point mutation, reduces drug binding and consequently confers resistance to macrolides. Finally, the macrolide resistance could be detected without sequencing by performing restriction fragment length polymorphism with appropriate restriction enzymes.

scholarly journals Phenotypic and Genotypic Analysis of Resistant Helicobacter pylori Strains Isolated from Children with Gastrointestinal Diseases

Diagnostics ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 759
Author(s):  
Monika Maria Biernat ◽  
Aldona Bińkowska ◽  
Łukasz Łaczmański ◽  
Paweł Biernat ◽  
Paweł Krzyżek ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Point Mutations ◽  
Gastrointestinal Diseases ◽  
Drug Susceptibility Testing ◽  
Test Method ◽  
Ulcer Disease ◽  
Genotypic Analysis ◽  
Clinical Diagnoses ◽  
H Pylori

Antibiotic resistance of Helicobacter pylori is currently a global issue. The aim of this study was to analyze actual antibiotic resistance rates of H. pylori strains isolated from children with primary infections and to compare the incidence of mutations that determine resistance to clarithromycin (CH) and metronidazole (MET) in children with different clinical diagnoses. A total of 91 H. pylori strains were isolated from 108 children with primary infections. Drug susceptibility testing of the strains was performed using E-test method. Classical sequencing of DNA fragments was used to detect point mutations for CH and MET resistance. Resistance to CH was detected in 31% of isolated strains (28/91), while resistance to MET and CH was detected in 35% (32/91) of strains. A2143G was the most frequently detected mutation and was dominant among strains isolated from children with peptic ulcer disease (80%). Mutations in the rdxA gene were found significantly more frequently among MET-resistant strains than MET-sensitive strains (p = 0.03, Chi2 = 4.3909). In children, a higher frequency of H. pylori multiresistant strains was observed compared with the previous study in the same area. Differences were found in the occurrence of point mutations among H. pylori strains resistant to CH isolated from children with different clinical diagnoses.

scholarly journals Mutated Rnf43 Aggravates Helicobacter Pylori-Induced Gastric Pathology

Cancers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 372 ◽  
Author(s):  
Victoria Neumeyer ◽  
Michael Vieth ◽  
Markus Gerhard ◽  
Raquel Mejías-Luque
Keyword(s):  
Helicobacter Pylori ◽  
Tumor Suppressor ◽  
Point Mutations ◽  
Ring Finger ◽  
Stem Cell Marker ◽  
Ring Finger Protein ◽  
Functional Studies ◽  
Finger Protein ◽  
H Pylori ◽  
Key Events

The E3 ubiquitin ligase ring finger protein 43 (RNF43) is frequently mutated in gastric tumors and loss of RNF43 expression was suggested to be one of the key events during the transition from adenoma to gastric carcinoma. Functional studies on RNF43 have shown that it acts as a tumor suppressor by negatively regulating Wnt signaling. Interestingly, we observed that RNF43H292R/H295R mice bearing two point mutations in the ring domain displayed thickening of the mucosa at early age but did not develop neoplasia. In this study, we infected these mice for 6 months with Helicobacter pylori, which has been described as one of the major risk factors for gastric cancer. Mice bearing mutant RNF43H292R/H295R showed higher gastritis scores upon H. pylori infection compared to wild-type mice, accompanied by increased lymphocyte infiltration and Ifng levels. Furthermore, infected Rnf43 mutant mice developed atrophy, hyperplasia and MUC2 expressing metaplasia and displayed higher levels of the gastric stem cell marker CD44 and canonical NF-κB signaling. In summary, our results show that transactivating mutations in the tumor suppressor Rnf43 can worsen H. pylori induced pathology.

scholarly journals Rapid screening of clarithromycin resistance in Helicobacter pylori by pyrosequencing

2007 ◽  
Vol 56 (10) ◽  
pp. 1370-1376 ◽  
Author(s):  
Karen-Anja Moder ◽  
Franziska Layer ◽  
Wolfgang König ◽  
Brigitte König
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
Rapid Screening ◽  
23S Rrna ◽  
Resistance Testing ◽  
Resistance Mutations ◽  
Additional Time ◽  
Clarithromycin Resistance ◽  
H Pylori ◽  
Domain V

Helicobacter pylori infections can be effectively treated with clarithromycin, a macrolide, in combination with other antibiotics, such as amoxicillin, tetracycline or metronidazole. The failure of H. pylori eradication is mainly associated with macrolide-resistant strains. Three point mutations (A2142G/C, A2143G, T2182C) in the peptidyltransferase region of domain V of the 23S rRNA have been described as being associated with clarithromycin resistance. Therefore, the determination of clarithromycin resistance by pyrosequencing was evaluated. H. pylori from 81 gastric biopsies was cultured and clarithromycin resistance was determined by Etest, as well as by pyrosequencing technology (PSQ 96 system; Biotage). The respective mutations were set in relation to the MIC measured in μg ml−1 by Etest. In this study, point mutations in positions 2142 and 2143 were associated with clarithromycin resistance. Mutations in position 2182 did not contribute to clarithromycin resistance. In addition, from 22 out of the 81 biopsies, clarithromycin resistance was determined directly without culturing H. pylori to save additional time. Identical results were obtained as compared to resistance testing with pure H. pylori strains. All results obtained by pyrosequencing were evaluated by Sanger sequencing. The data show that pyrosequencing to detect point mutation is a fast and reliable method for determining clarithromycin resistance in H. pylori, and provides the same results as the Etest.

scholarly journals Rapid Detection, by PCR and Reverse Hybridization, of Mutations in the Helicobacter pylori 23S rRNA Gene, Associated with Macrolide Resistance

1999 ◽  
Vol 43 (7) ◽  
pp. 1779-1782 ◽  
Author(s):  
Leen-Jan van Doorn ◽  
Yvette J. Debets-Ossenkopp ◽  
Armelle Marais ◽  
Ricardo Sanna ◽  
Francis Mégraud ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Fragment Length Polymorphism ◽  
Simultaneous Detection ◽  
Point Mutations ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Reverse Hybridization ◽  
23S Rrna Gene ◽  
H Pylori

ABSTRACT A PCR-based reverse hybridization system (research prototype kit INNO-LiPA for H. pylori resistance) was developed and evaluated for simultaneous detection of 23S ribosomal DNA point mutations, associated with macrolide resistance in Helicobacter pylori. Fifty-seven H. pylori strains (51 natural, 6 laboratory-derived artificial, 52 resistant, and 5 susceptible strains) were tested by PCR-LiPA (detecting mutations A2115→G, G2141→A, A2142→G, A2142→C, A2143→G, A2143→C, and A2143→T), DNA sequencing, restriction fragment length polymorphism, and/or hybridization to oligonucleotide probes. Results were highly concordant, but PCR-LiPA appears to be more sensitive for the simultaneous detection of multiple mutants.

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.

Helicobacter pylori-induced H,K-ATPase α-subunit gene repression is mediated by NF-κB p50 homodimer promoter binding

2008 ◽  
Vol 294 (3) ◽  
pp. G795-G807 ◽  
Author(s):  
Arindam Saha ◽  
Charles E. Hammond ◽  
Maria Trojanowska ◽  
Adam J. Smolka
Keyword(s):  
Helicobacter Pylori ◽  
Mapk Pathway ◽  
Point Mutations ◽  
Gastric Body ◽  
Ags Cells ◽  
Α Subunit ◽  
Cell Enzyme ◽  
Dna Protein Interaction ◽  
H Pylori ◽  
Interfering Rna

Infection of human gastric body mucosa by the gram-negative, microaerophilic bacterium Helicobacter pylori induces an inflammatory response and a transitory hypochlorhydria that progresses in ∼2% of patients to atrophic gastritis, dysplasia, and gastric adenocarcinoma. We have previously shown that H. pylori infection of cultured gastric epithelial cells (AGS) represses the activity of the transfected α-subunit (HKα) promoter of H,K-ATPase, the parietal cell enzyme mediating acid secretion. However, the mechanistic details of H. pylori-mediated repression of HKα and ensuing hypochlorhydria are unknown. H. pylori is known to upregulate the transcription factor NF-κB through the ERK1/2 MAPK pathway. We identified NF-κB-binding regions in the HKα promoter and found that H. pylori inoculation of AGS cells increased NF-κB p50 binding to the transfected HKα promoter and repressed its transcriptional activity. Immunoblot and DNA-protein interaction studies showed that although active phosphorylated NF-κB p65 is present in H. pylori-infected AGS cells, an NF-κB p50/p65 heterodimeric complex fails to bind to the HKα promoter. Point mutations at −159 and −161 bp in the HKα promoter NF-κB binding sequence prevented binding of NF-κB p50 and prevented H. pylori repression of point-mutated HKα promoter activity in transfected AGS cells. Small interfering RNA-mediated knockdown of NF-κB p50 in H. pylori-infected AGS cells also abrogated H. pylori-induced HKα repression, whereas NF-κB p65 knockdown did not. We conclude that H. pylori inhibits HKα gene expression by ERK1/2-mediated NF-κB p50 homodimer binding to the HKα promoter. This study identifies a novel pathogen-dependent mechanism of H,K-ATPase inhibition and contributes to understanding of H. pylori pathophysiology.

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.

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