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

• Main Authors: Monique Ribeiro Tiba-Casas, Cláudio Tavares Sacchi, Cláudia Regina Gonçalves, Elisabete Aparecida Almeida, Flávia Barrosa Soares, Amanda Maria de Jesus Bertani, Sueli Aparecida Fernandes, Maria Bernadete de Paula Eduardo, Carlos Henrique Camargo
• Format: Article
• Language: English
• Published: Elsevier 2019-04-01
• Series: International Journal of Infectious Diseases
• Online Access: http://www.sciencedirect.com/science/article/pii/S1201971219300736

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: Salmonella Typhi, Whole genome sequencing, Phylogenetic, Antimicrobial resistance