title: Phenotypic and genotypic analysis of clarithromycin-resistant Helicobacter pylori from Bogotá D.C., Colombia.
abstract: 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.
authors.affiliation: Infectious Diseases Group, Microbiology Department, Science Faculty, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia. alba.trespalacios@javeriana.edu.co
authors.forename: Alba A
authors.initials: AA
authors.lastname: Trespalacios
authors.forename: William
authors.initials: W
authors.lastname: Otero
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Caminos
authors.forename: Marcela M
authors.initials: MM
authors.lastname: Mercado
authors.forename: Jenny
authors.initials: J
authors.lastname: Avila
authors.forename: Liliana E
authors.initials: LE
authors.lastname: Rosero
authors.forename: Azucena
authors.initials: A
authors.lastname: Arévalo
authors.forename: Raúl A
authors.initials: RA
authors.lastname: Poutou-Piñales
authors.forename: David Y
authors.initials: DY
authors.lastname: Graham
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017291:Clarithromycin / Q000494:pharmacology*; D003105:Colombia; D004252:DNA Mutational Analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D012338:RNA, Ribosomal, 23S; D017291:Clarithromycin