title: Primary resistance of Helicobacter pylori to antimicrobial agents in Polish children.
abstract: Helicobacter pylori resistance to antimicrobial agents is an important factor compromising the efficacy of treatment. Therefore the aims of our study were: to determine the prevalence of H. pylori resistance to clarithromycin, metronidazole, amoxycillin and tetracycline in children prior to eradication therapy, to compare different methods of susceptibility testing and to detect mutations responsible for clarithromycin resistance. During 1996-2000, 259 H. pylori strains were isolated from antral gastric biopsies. Susceptibility to antimicrobials was determined by the agar dilution method and the Etest. Mutations in the 23S rRNA gene associated with clarithromycin resistance were analysed by PCR-RFLP and direct sequencing. Overall, ninety-six strains (37%) were resistant to metronidazole, 50 strains (19.3%) were resistant to clarithromycin, and 20 strains (7.7%) were simultaneously resistant to both drugs. All cultured isolates were sensitive to amoxycillin and only one isolate (0.4%) was resistant to tetracycline. The agar dilution method and the Etest showed a perfect category correlation for clarithromycin and 4% discrepancies for metronidazole. Primary resistance to clarithromycin was mainly associated with an A2143G mutation in the 23S rRNA gene of H. pylori. The study highlights the high prevalence of H. pylori primary resistance to clarithromycin in Polish children, which implies a need for pretreatment susceptibility testing.
authors.affiliation: Department of Clinical Microbiology and Immunology, Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-736 Warsaw, Poland.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Rozynek
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Dzierzanowska-Fangrat
authors.forename: Danuta
authors.initials: D
authors.lastname: Celińska-Cedro
authors.forename: Paulina
authors.initials: P
authors.lastname: Jóźwiak
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Madaliński
authors.forename: Danuta
authors.initials: D
authors.lastname: Dzierzanowska
mesh_terms: D000293:Adolescent; D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D017291:Clarithromycin / Q000494:pharmacology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007410:Intestinal Diseases / Q000188:drug therapy / Q000382:microbiology*; D008795:Metronidazole / Q000494:pharmacology; D011044:Poland; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D012338:RNA, Ribosomal, 23S; D008795:Metronidazole; D000658:Amoxicillin; D013752:Tetracycline; D017291:Clarithromycin