Acquisition of double mutation in gyrA caused high resistance to sitafloxacin in Helicobacter pylori after unsuccessful eradication with sitafloxacin-containing regimens

Hideki Mori, Hidekazu Suzuki, Juntaro Matsuzaki, Tatsuhiro Masaoka, Takanori Kanai

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10 Citations (Scopus)


Background and aim: Although sitafloxacin (STFX)-containing regimens are effective rescue treatments for Helicobacter pylori infection, prevalence of fluoroquinolone resistance in H. pylori has increased rapidly worldwide. The change in resistance levels and gyrA mutations, a major cause of fluoroquinolone resistance, after unsuccessful STFX-containing treatment has not been investigated. Methods: We conducted a retrospective, non-randomized study to compare the minimum inhibitory concentrations (MICs) of STFX and the location of gyrA mutations in H. pylori before and after unsuccessful eradication with STFX-containing regimens at Keio University Hospital between December 2011 and March 2015. Results: A total of 266 patients treated with STFX-containing regimens for third-line H. pylori eradication were evaluated. Double mutations in gyrA were acquired by 20.8% of strains that exhibited seven-fold increased STFX MICs, compared to pre-treatment MICs. The STFX MICs did not increase, however, when the location of the gyrA mutations did not change after treatment. Double mutations in gyrA developed in 60.0% of the strains in which eradication failed, which exhibited a baseline mutation at position D91, and in 11.1% of strains with baseline mutations at position N87. Conclusion: Acquisition of double mutations in gyrA evoked high-level resistance to STFX in H. pylori after unsuccessful eradication with STFX-containing regimens.

Original languageEnglish
Pages (from-to)391-397
Number of pages7
JournalUnited European Gastroenterology Journal
Issue number3
Publication statusPublished - 2018 Apr 1



  • Helicobacter pylori
  • double mutation
  • gyrA
  • minimum inhibitory concentration
  • sitafloxacin

ASJC Scopus subject areas

  • Oncology
  • Gastroenterology

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