title: Antimicrobial resistance and characterization of Helicobacter pylori strains isolated from Mexican adults with clinical outcome.
abstract: Eradication of Helicobacter pylori infection in Mexico is of great importance due to the elevated seroprevalence, however, there is yet very little information about antibiotic resistance rates in H. pylori isolates in our country. We analyzed susceptibility to three antimicrobials used in therapy of 49 H. pylori strains isolated from patients with active chronic gastritis, active chronic gastritis with lymphoid follicles, intestinal metaplasia and gastric cancer. All isolated strains were susceptible to amoxicillin, 28 (58%) were resistant to metronidazole and 2 (4%) were resistant to both clarithromycin and metronidazole. Sequence analysis of the 23S rRNA of the two clarithromycin-resistant strains showed the A2142G mutation in one and A2143G and T2182C mutations in the other. Metronidazole resistance was associated with cagA negative strains with a frequency of 82% (9/11). No significant correlation was found between vacA s/m alleles and metronidazole resistance.
authors.affiliation: National Institute of Public Health, SSA, Cuernavaca, Morelos, Mexico.
authors.forename: L
authors.initials: L
authors.lastname: Chihu
authors.forename: G
authors.initials: G
authors.lastname: Ayala
authors.forename: A
authors.initials: A
authors.lastname: Mohar
authors.forename: A
authors.initials: A
authors.lastname: Hernández
authors.forename: R
authors.initials: R
authors.lastname: Herrera-Goepfert
authors.forename: G
authors.initials: G
authors.lastname: Fierros
authors.forename: H
authors.initials: H
authors.lastname: González-Márquez
authors.forename: J
authors.initials: J
authors.lastname: Silva
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial; D005260:Female; D005756:Gastritis / Q000382:microbiology; D005838:Genotype; D016481:Helicobacter Infections; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008800:Mexico; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012335:RNA, Ribosomal / Q000032:analysis; D017422:Sequence Analysis, DNA; D016896:Treatment Outcome; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D012335:RNA, Ribosomal