Molecular analysis of clonally related Salmonella Typhi recovered from epidemiologically unrelated cases of typhoid fever, Brazil

Int J Infect Dis. 2019 Apr:81:191-195. doi: 10.1016/j.ijid.2019.02.009. Epub 2019 Mar 5.

Abstract

Background: The primary method of molecular subtyping for the identification and investigation of outbreaks has been pulsed-field gel electrophoresis (PFGE). In some cases, this technique has not been able to show discrimination between the unrelated strains that can be achieved by whole genome sequencing (WGS).

Methods: The aim of this study was to determine the strengths and drawbacks of WGS using different analytic approaches compared to traditional typing method, PFGE, for retrospectively typing clusters cases of 28 S. Typhi.

Results: We evaluated three analytical approaches on the WGS data set (Nucleotide Difference (ND), (SNPs) and Whole genome multi locus sequence typing (wgMLST) that identically classified the clusters-related strains into two clusters, cluster A (with strains from 2017), and Cluster B (with strains from 2007).

Conclusions: In this study WGS based typing, was able to compete with PFGE for differentiation of the clusters of S. Typhi strains.

Keywords: Antimicrobial resistance; Phylogenetic; Salmonella Typhi; Whole genome sequencing.

MeSH terms

  • Anti-Bacterial Agents / administration & dosage
  • Brazil / epidemiology
  • Child, Preschool
  • Disease Outbreaks
  • Electrophoresis, Gel, Pulsed-Field
  • Female
  • Humans
  • Male
  • Multilocus Sequence Typing
  • Retrospective Studies
  • Salmonella typhi / drug effects
  • Salmonella typhi / genetics*
  • Salmonella typhi / isolation & purification*
  • Salmonella typhi / physiology
  • Typhoid Fever / drug therapy
  • Typhoid Fever / epidemiology
  • Typhoid Fever / microbiology*
  • Whole Genome Sequencing

Substances

  • Anti-Bacterial Agents