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

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AUTHORS

Tiba-Casas MR, Sacchi CT, Gonçalves CR, Almeida EA, Soares FB, de Jesus Bertani AM, Fernandes SA, de Paula Eduardo MB, Camargo CH.

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.

Click here to view the article, published in International Journal of Infectious Diseases.