Impact of mutations in DNA gyrase genes on quinolone resistance in Campylobacter jejuni

Ruchirada Changkwanyeun, Tomoyuki Yamaguchi, Siriporn Kongsoi, Kanjana Changkaew, Kazumasa Yokoyama, Hyun Kim, Orasa Suthienkul, Masaru Usui, Yutaka Tamura, Chie Nakajima, Yasuhiko Suzuki

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Amino acid substitutions providing quinolone resistance to Campyloabcter jejuni have been found in the quinolone resistance-determining region of protein DNA gyrase subunit A (GyrA), with the highest frequency at position 86 followed by position 90. In this study, wild-type and mutant recombinant DNA gyrase subunits were expressed in Escherichia coli and purified using Ni-NTA agarose column chromatography. Soluble 97 kDa GyrA and 87 kDa DNA gyrase subunit B were shown to reconstitute ATP-dependent DNA supercoiling activity. A quinolone-inhibited supercoiling assay demonstrated the roles of Thr86Ile, Thr86Ala, Thr86Lys, Asp90Asn, and Asp90Tyr amino acid substitutions in reducing sensitivity to quinolones. The marked effect of Thr86Ile on all examined quinolones suggested the advantage of this substitution in concordance with recurring isolation of quinolone-resistant C. jejuni. An analysis of the structure-activity relationship showed the importance of the substituent at position 8 in quinolones to overcome the effect of Thr86Ile. Sitafloxacin (SIT), which has a fluorinate cyclopropyl ring at R-1 and a chloride substituent at R-8, a characteristic not found in other quinolones, showed the highest inhibitory activity against all mutant C. jejuni gyrases including ciprofloxacin-resistant mutants. The results suggest SIT as a promising drug for the treatment of campylobacteriosis caused by CIP-resistant C. jejuni.

Original languageEnglish
Pages (from-to)1071-1076
Number of pages6
JournalDrug Testing and Analysis
Volume8
Issue number10
DOIs
Publication statusPublished - Oct 1 2016
Externally publishedYes

Keywords

  • Campylobacter jejuni
  • DNA gyrase
  • mutation
  • quinolone resistance

ASJC Scopus subject areas

  • Analytical Chemistry
  • Environmental Chemistry
  • Pharmaceutical Science
  • Spectroscopy

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