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Punctual mutations in 23S rRNA gene of clarithromycinresistant Helicobacter pylori in Colombian populations

World Journal of Gastroenterology 2018年第14期24卷 1531-1539页

作者： Andrés Jenuer Matta Diana Carolina Zambrano alvaro jairo pazos Registro Poblacional de Cáncer de Cali Department of Pathology School of Medicine Universidad del Valle Faculty of Education and Sports Sciences Institución Universitaria Escuela Nacional del Deporte Department of Biology Universidad de Nari?o

AIM To characterize punctual mutations in 23S rRNA gene of clarithromycin-resistant Helicobacter pylori(H. pylori) and determine their association with therapeutic *** PCR products of 23S rRNA gene V domain of 74 H. pylori isolates; 34 resistant to clarithromycin(29 from a low-risk gastric cancer(GC) population: TumacoColombia, and 5 from a high-risk population: TuquerresColombia) and 40 from a susceptible population(28 from Tumaco and 12 from Túquerres) were sequenced using capillary electrophoresis. The concordance between mutations of V domain 23S rRNA gene of H. pylori and therapeutic failure was determined using the Kappa coefficient and Mc Nemar's test was performed to determine the relationship between H. pylori mutationsand clarithromycin ***23S rRNA gene from H. pylori was amplified in 56/74 isolates, of which 25 were resistant to clarithromycin(20 from Tumaco and 5 from Túquerres, respectively). In 17 resistant isolates(13 from Tumaco and 4 from Túquerres) the following mutations were found: A1593 T1, A1653 G2, C1770 T, C1954 T1, and G1827 C in isolates from Tumaco, and A2144 G from Túquerres. The mutations T2183 C, A2144 G and C2196 T in H. pylori isolates resistant to clarithromycin from Colombia are reported for the first time. No association between the H. pylori mutations and in vitro clarithromycin resistance was found. However, therapeutic failure of eradication treatment was associated with mutations of 23S rRNA gene in clarithromycin-resistant H. pylori(κ = 0.71).CONCLUSION The therapeutic failure of eradication treatment in the two populations from Colombia was associated with mutations of the 23S rRNA gene in clarithromycinresistant H. pylori.

关键词： Clarithromycin In vitro resistance Point mutation Helicobacter pylori Gastric cancer 23S rRNA

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Effect of treatment failure on the Cag A EPIYA motif in Helicobacter pylori strains from Colombian subjects

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World Journal of Gastroenterology 2017年第11期23卷 1980-1989页

作者： Javier Andres Bustamante-Rengifo Andres Jenuer Matta alvaro jairo pazos Luis Eduardo Bravo Department of Microbiology School of Basic ScienceUniversidad del Valle Registro Poblacional de Cáncer de Cali Department of PathologySchool of MedicineUniversidad del Valle Department of Biology Universidad de Narino

AIM To evaluate effect of treatment failure on cag A and vac A genotypes in Helicobacter pylori(H. pylori) isolates from *** One hundred and seventy-six participants infected with H. pylori from Colombia were treated during 14 d with the triple-standard therapy. Six weeks later, eradication was evaluated by 13C-Urea breath test. Patients with treatment failure were subjected to endoscopy control; biopsies obtained were used for histopathology and culture. DNA from H. pylori isolates was amplified using primers specific for cag A and vac A genes. The phylogenetic relationships among isolates obtained before and after treatment were established by conglomerate analysis based on random amplified polymorphic DNA(RAPD) *** Treatment effectiveness was at 74.6%. Of the par-ticipants with treatment failure, 25 accepted subjected to a second endoscopy. Prevalence of posttreatment infection was 64%(16/25) and 40%(10/25) by histology and culture, respectively. Upon comparing the cag A and vac A genotypes found before and after therapy, multiple cag A genotypes(cag A-positive and cag A-negative) were found before treatment; in contrast, cag A-negative genotypes decreased after treatment. vac A s1m1 genotype was highly prevalent in patients before and after therapy. The 3'cag A region was successfully amplified in 95.5%(21/22) of the isolates obtained before and in 81.8%(18/22) of the isolates obtained after treatment. In the isolates obtained from patients with treatment failure, it was found that 72.7%(16/22) presented alterations in the number of EPIYA motifs, compared to isolates found before *** Unsuccessful treatment limits colonization by lowvirulence strains resulting in partial and selective eradication in mixed infections, and acts on the cag A-positive strains inducing genetic rearrangements in cag A variable region that produces a loss or gain of EPIYA repetitions.

关键词： Helicobacter pylori RAPD-PCR Treatment failure EPIYA motifs 3’ cag A variable region

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Genomic variability of Helicobacter pylori isolates of gastric regions from two Colombian populations

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World Journal of Gastroenterology 2017年第5期23卷 800-809页

作者： Andrés Jenuer Matta alvaro jairo pazos Javier Andrés Bustamante-Rengifo Luis Eduardo Bravo Registro Poblacional de Cáncer de Cali Department of PathologySchool of MedicineUniversidad del Valle Department of Biology Universidad de Narino

AIMTo compare the genomic variability and the multiple colonization of Helicobacter pylori (H. pylori) in patients with chronic gastritis from two Colombian populations with contrast in the risk of developing gastric cancer (GC): Túquerres-Nariño (High risk) and Tumaco-Nariño (Low risk).METHODSFour hundred and nine patients from both genders with dyspeptic symptoms were studied. Seventy-two patients were included in whom H. pylori was isolated from three anatomic regions of the gastric mucosa, (31/206) of the high risk population of GC (Túquerres) and (41/203) of the low risk population of GC (Tumaco). The isolates were genotyped by PCR-RAPD. Genetic diversity between the isolates was evaluated by conglomerates analysis and multiple correspondence *** proportion of virulent genotypes of H. pylori was 99% in Túquerres and 94% in Tumaco. The coefficient of similarity of Nei-Li showed greater genetic diversity among isolates of Túquerres (0.13) than those of Tumaco (0.07). After adjusting by age, gender and type of gastritis, the multiple colonization was 1.7 times more frequent in Túquerres than in Tumaco (P = 0.05).CONCLUSIONIn Túquerres, high risk of GC there was a greater probability of multiple colonization by H. pylori. From the analysis of the results of the PCR-RAPD, it was found higher genetic variability in the isolates of H. pylori in the population of high risk for the development of GC.

关键词： Helicobacter pylori Pathogenicity islet cag cagA vacA Multiple colonization PCR-RAPD

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In vitro effect of amoxicillin and clarithromycin on the 3' region of cagA gene in Helicobacter pylori isolates

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World Journal of Gastroenterology 2013年第36期19卷 6044-6054页

作者： Javier Andrés Bustamante-Rengifo Andrés Januer Matta alvaro pazos Luis Eduardo Bravo Registro Poblacional de Cáncer de Cali Department of Pathology School of Medicine Universidad del Valle Department of Biology Universidad de Nario

AIM:To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island(cag PAI).METHODS:One hundred and forty-nine clinical isolates of Helicobacter pylori(***)cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study *** susceptibility was determined by the agar dilution *** isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping(cagA,vacA alleles s and m),Glu-Pro-Ile-Tyr-Ala(EPIYA)polymerase chain reaction and random amplified polymorphic DNA(RAPD).Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer *** analyses was done using SPSS 15.0statistical package,where each of the fingerprint bands were denoted as *** were designed by following Ward’s clustering method and the estimation of distances between each pair of *** isolates was calculated with the squared Euclidean ***:Resistance rates were 4%for amoxicillin and 2.7%for clarithromycin with 2%double *** evidenced a high prevalence of the genotype cagA-positive/vacA *** 3’region of cagA gene was successfully amplified in 92.3%(12/13)of the baseline resistant isolates and in 60%(36/60)of the resistant isolates growing in antibiotic *** observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates,it was found that in 61.5%(8/13)of the baseline isolates,a change in the number of EPIYA repetitions lowered antibiotic *** gain and loss of EPIYA motifs resulted in a diversity of *** subclones after bacterial adjustment to changing conditions product of antibiotic *** PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic ***:Antibiotic pressure does not induce loss of the cag pathoge

关键词： Helicobacter pylori Antimicrobial susceptibility cag pathogenicity island cagA 3’region Random amplified polymorphic DNA-polymerase chain reaction

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