title: Primary antibiotic resistance and associated mechanisms in Helicobacter pylori isolates from Senegalese patients.
abstract: BACKGROUND
  Antibiotic combination therapy for Helicobacter pylori eradication must be adapted to local resistance patterns, but the epidemiology of H. pylori resistance to antibiotics is poorly documented in Africa. The aim was to determine the antibiotic resistance rates, as well as the associated molecular mechanisms, of strains isolated in Dakar, Senegal.
  
  
  METHODS
  One hundred and eight H. pylori strains were isolated between 2007 and 2009 from 108 patients presenting with upper abdominal pain to the Gastroenterology Department of Le Dantec Hospital. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, levofloxacin and tetracyclin using the E-test method. Mutations in the 23S rRNA gene of clarithromycin-resistant strains and in gyrA and gyrB of levofloxacin-resistant strains were investigated.
  
  
  RESULTS
  Isolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), and very low rate of resistance to clarithromycin (1%), but a high rate of resistance to metronidazole (85%). The clarithromycin-resistant strain displayed the A2143G mutation. A worrying rate of levofloxacin resistance was detected (15%). N87I and D91N were the most common mutations in the quinolone-resistance-determining region of gyrA.
  
  
  CONCLUSIONS
  The first-line empirical regimen for H. pylori eradication in Senegal should include clarithromycin. Increasing rates of fluoroquinolone resistance detected should discourage the use of levofloxacin-containing regimens without prior antimicrobial susceptibility testing.
authors.affiliation: Institut Pasteur, Unité de Biologie Médicale et Environnementale, 36 avenue pasteur, Dakar, Senegal.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Seck
authors.forename: Christophe
authors.initials: C
authors.lastname: Burucoa
authors.forename: Daouda
authors.initials: D
authors.lastname: Dia
authors.forename: Mouhamadou
authors.initials: M
authors.lastname: Mbengue
authors.forename: Manuella
authors.initials: M
authors.lastname: Onambele
authors.forename: Josette
authors.initials: J
authors.lastname: Raymond
authors.forename: Sebastien
authors.initials: S
authors.lastname: Breurec
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000494:pharmacology; D017291:Clarithromycin / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D015242:Ofloxacin / Q000494:pharmacology; D012338:RNA, Ribosomal, 23S; D012675:Senegal; D013752:Tetracycline / Q000494:pharmacology; D055815:Young Adult
chemical_list: D012338:RNA, Ribosomal, 23S; D008795:Metronidazole; D064704:Levofloxacin; D000658:Amoxicillin; D015242:Ofloxacin; D027081:DNA Gyrase; D013752:Tetracycline; D017291:Clarithromycin