Journal Article
- Comparative Proteomics Analysis of Sarcosine Insoluble Outer Membrane Proteins from Clarithromycin Resistant and Sensitive Strains of Helicobacter pylori
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Rebecca Smiley , James Bailey , Mahadevan Sethuraman , Norberto Posecion , M. Showkat Ali
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J. Microbiol. 2013;51(5):612-618. Published online October 31, 2013
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DOI: https://doi.org/10.1007/s12275-013-3029-5
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Abstract
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Helicobacter pylori causes disease manifestations in humans including chronic gastric and peptic ulcers, gastric cancer, and lymphoid tissue lymphoma. Increasing rates of H. pylori clarithromycin resistance has led to higher rates of disease development. Because antibiotic resistance involves modifications of outer membrane proteins (OMP) in other Gram-negative bacteria, this study focuses on identification of H. pylori OMP’s using comparative proteomic analyses of clarithromycin-susceptible and -resistant H. pylori strains. Comparative proteomics analyses of isolated sarcosine-insoluble OMP fractions from clarithromycin-susceptible and -resistant H. pylori strains were performed by 1) one dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis protein separation and 2) in-gel digestion of the isolated proteins and mass spectrometry analysis by Matrix Assisted Laser Desorption Ionization-tandem mass spectrometry. Iron-regulated membrane protein, UreaseB, EF-Tu, and putative OMP were down-regulated; HopT (BabB) transmembrane protein, HofC, and OMP31 were up-regulated in clarithromycin-resistant H. pylori. Western blotting and real time PCR, respectively, validated UreaseB subunit and EF-Tu changes at the protein level, and mRNA expression of HofC and HopT. This limited proteomic study provides evidence that alteration of the outer membrane proteins’ profile may be a novel mechanism involved in clarithromycin resistance in H. pylori.
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Research Support, Non-U.S. Gov't
- Phenotypic and Genotypic Analysis of Clarithromycin-Resistant Helicobacter pylori from Bogotá D.C., Colombia
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Alba A. Trespalacios , William Otero , Jorge E. Caminos , Marcela M. Mercado , Jenny Ávila , Liliana E. Rosero , Azucena Arévalo , Raúl A. Poutou-Piñales , David Y. Graham
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J. Microbiol. 2013;51(4):448-452. Published online August 30, 2013
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DOI: https://doi.org/10.1007/s12275-013-2465-6
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22
Scopus
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Abstract
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Resistance of Helicobacter pylori to clarithromycin is the most common cause of treatment failure in patients with H. pylori infections. This study describes the MICs and the presence of 23S rRNA mutations of H. pylori isolates from Bogotá, D.C., Colombia. H. pylori were isolated from gastric biopsies from patients with functional dyspepsia. Clarithromycin susceptibility was investigated by agar dilution and strains were considered resistant if the MIC was ≥1 μg/ml. DNA sequences of the 23S rRNA gene of strains resistant and sensitive to clarithromycin were determined to identify specific point mutations. Clarithromycin resistance was present in 13.6% of patients by agar dilution. The A2143G, A2142G and A2142C mutations were found in 90.5, 7.1, and 2.4% of H. pylori strains with resistance genotype.The resistant phenotype was associated with 23S rRNA resistance genotype in 85.7% of isolates. The point mutations in 23S rRNA were well correlated with MICs values for clarithromycin.
Journal Article
- Claritromycin Resistance and Helicobacter pylori Genotypes in Italy
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Vincenzo De Francesco , Marcella Margiotta , Cesare Hassan , Nicola Della Valle , Osvaldo Burattini , Roberto D’Angelo , Giuseppe Stoppino , Ugo Cea , Floriana Giorgio , Rosa Monno , Sergio Morini , Carmine Panella , Enzo Ierardi
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J. Microbiol. 2006;44(6):660-664.
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DOI: https://doi.org/2460 [pii]
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Abstract
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The relationship between H. pylori clarithromycin resistance and genetic pattern distribution has been differently explained from different geographic areas. Therefore, we aimed to assess the clarithromycin resistance rate, to evaluate the bacterial genetic pattern, and to search for a possible association between clarithromycin resistance and cagA or vacA genes. This prospective study enrolled 62 consecutive H. pylori infected patients. The infection was established by histology and rapid urease test. Clarithromycin resistance, cagA and vacA status, including s/m subtypes, were assessed on paraffin-embedded antral biopsy specimens by TaqMan real time polymerase chain reaction (PCR). Primary clarithromycin resistance was detected in 24.1% of cases. The prevalence of cagA was 69.3%, and a single vacA mosaicism was observed in 95.1% cases. In detail, the s1m1 was observed in 23 (38.9%) patients, the s1m2 in 22 (37.2%), and the s2m2 in 14 (23.7%), whereas the s2m1 combination was never found. The prevalence of cagA and the vacA alleles distribution did not significantly differ between susceptible and resistant strains. Primary clarithromycin resistance is high in our area. The s1m1 and s1m2 are the most frequent vacA mosaicisms. There is no a relationship between clarithromycin resistance and bacterial genotypic pattern and/or cagA positivity.
Research Support, Non-U.S. Gov't
- Clarithromycin Resistance Prevalence and Icea Gene Status in Helicobacter Pylori Clinical Isolates in Turkish Patients with Duodenal Ulcer and Functional Dyspepsia
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Peren H. Baglan , Gulendam Bozdayi , Muhip Ozkan , Kamruddin Ahmed , A. Mithat Bozdayi , Ali Ozden
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J. Microbiol. 2006;44(4):409-416.
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DOI: https://doi.org/2412 [pii]
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Abstract
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Clarithromycin resistance in Helicobacter pylori is a principal cause of failure of eradication therapies, and its prevalence varies geographically. The IceA gene is a virulence factor associated with clinical outcomes. The objective of this study was to determine the current state of clarithromycin resistance prevalence, and to investigate the role of iceA genotypes in 87 Turkish adult patients (65 with functional dyspepsia and 22 with duodenal ulcer). A2143G and A2144G point mutations were tested by PCR-RFLP for clarithromycin resistance. Among the patients in the study, 28 patients were tested by agar dilution as well. Allelic variants of the iceA gene were identified by PCR. A total of 24 (27.6%) strains evidenced one of the mutations, either A2143G or A2144G. IceA1 was found to be positive in 28 of the strains (32.2%), iceA2 was positive in 12 (13.8%) and, both iceA1 and iceA2 were positive in 22 (25.3%) strains. In conclusion, we discovered no relationships between
iceA genotypes and functional dyspepsia or duodenal ulcer, nor between clarithromycin resistance and iceA genotypes. Clarithromycin resistance appears to be more prevalent in Turkish patients.