Detection of mutations in gyrB using denaturing high performance liquid chromatography (DHPLC) among Salmonella enterica serovar Typhi and Paratyphi A

Ruchi Gupta, Rajni Gaind (Lead Author), Laishram Chandreshwor Singh, Bianca Paglietti, Monorama Deb, Salvatore Rubino, John Wain, Seemi Farhat Basir

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Background:- Fluoroquinolone resistance is mediated by mutations in the quinolone-resistance determining region (QRDR) of the topoisomerase genes. Denaturing high performance liquid chromatography (DHPLC) was evaluated for detection of clinically important mutations in gyrB among Salmonella.

Method:- S. Typhi and S. ParatyphiA characterised for mutation in QRDR of gyrA, parC and parE were studied for mutation in gyrB by DHPLC and validated by sequencing.

Result:- The DHPLC analysis was able to resolve the test mutant from isolates with wild type gyrB and distinguished mutants from other mutant by peak profile and shift in retention time. Three sequence variants were detected at codon 464, and a novel mutation Ser→Thr was also detected. gyrB mutation was associated with non classical quinolone resistance (NALS-CIPDS) in 34 isolates of S. Typhi only and was distinct from classical quinolone resistance associated with gyrA mutations (NALR-CIPDS).

Conclusion: DHPLC is effective for the detection of mutation and can reduce the need forsequencing to detect clinically significant gyrB mutations..
Original languageEnglish
Pages (from-to)684-689
Number of pages6
JournalTransactions of the Royal Society of Tropical Medicine and Hygiene
Issue number12
Publication statusPublished - 7 Mar 2017


  • Decreased ciprofloxacin susceptibility
  • gyrB mutation
  • Salmonella Paratyphi A
  • Salmonella Typhi

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