title: Helicobacter pylori antibiotic resistance patterns and genotypes in adult dyspeptic patients from a regional population in North Wales.
abstract: OBJECTIVE
  Surveillance data on Helicobacter pylori antibiotic susceptibilities in Wales are limited, despite resistance being a key factor in treatment failure. A single-centre survey was undertaken over 3 years to determine local antibiotic resistance rates on isolates from dyspeptic patients in Bangor, Gwynedd (North Wales).
  
  
  METHODS
  Susceptibilities were determined for 363 isolates by disc diffusion and the Etest. Isolates were also genotyped (cagA presence and vacA allelic types).
  
  
  RESULTS
  Overall in vitro resistance rates were 24% for metronidazole and 7% for clarithromycin, with 4% resistant to both antibiotics. Resistant strains typically had high MICs of >256 mg/L. Tetracycline resistance was identified in only one isolate whereas no isolates showed resistance to amoxicillin. There was a two-fold increase in resistance over the study period. No gender and age associations with resistance were detected. Resistant and susceptible isolates were genotypically diverse with respect to cagA/vacA type but the vacA s1m2 form was a feature of all clarithromycin-resistant isolates compared with 56% of the susceptible isolates.
  
  
  CONCLUSIONS
  Although the overall antibiotic resistance rates of H. pylori from North Wales were low compared with many other regions in Europe, continued surveillance, particularly of high-level resistance (MIC >256 mg/L), is recommended to monitor the effects of the 'test and treat' strategy for H. pylori eradication.
authors.affiliation: Laboratory of Enteric Pathogens, Health Protection Agency, Specialist and Reference Microbiology Division, 61 Colindale Avenue, London NW9 5HT, UK.
authors.forename: Nicola C
authors.initials: NC
authors.lastname: Elviss
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Owen
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Xerry
authors.forename: A Mark
authors.initials: AM
authors.lastname: Walker
authors.forename: Kenneth
authors.initials: K
authors.lastname: Davies
mesh_terms: D000328:Adult; D000367:Age Factors; D000483:Alleles; D004351:Drug Resistance; D004415:Dyspepsia / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial / Q000235:genetics; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012737:Sex Factors; D014852:Wales / Q000453:epidemiology