Genotyping Study of Salmonella 4,,12:i:- Monophasic Variant of Serovar Typhimurium and Characterization of the Second-Phase Flagellar Deletion by Whole Genome Sequencing
Arrieta Gisasola, Ainhoa
Achaerandio Landa, Aitor
Grilló, María Jesús
Martínez Ballesteros, Ilargi
Laorden Muñoz, Lorena
Garaizar Candina, Javier
Bikandi Bikandi, Joseba
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Microorganisms 8(12) : (2020) // Article ID 2049
After Salmonella Enteritidis and S. Typhimurium, S. 4,,12:i:- is the most reported serovar in human clinical cases. During the past 20 years, many tools have been used for its typing and second-phase flagellar deletion characterization. Currently, whole genome sequencing (WGS) and different bioinformatic programs have shown the potential to be more accurate than earlier tools. To assess this potential, we analyzed by WGS and in silico typing a selection of 42 isolates of S. 4,,12:i:- and S. Typhimurium with different in vitro characteristics. Comparative analysis showed that SeqSero2 does not differentiate fljB-positive S. 4,,12:i:- strains from those of serovar Typhimurium. Our results proved that the strains selected for this work were non-clonal S. 4,,12:i:- strains circulating in Spain. Using WGS data, we identified 13 different deletion types of the second-phase flagellar genomic region. Most of the deletions were generated by IS26 insertions, showing orientation-dependent conserved deletion ends. In addition, we detected S. 4,,12:i:- strains of the American clonal line that would give rise to the Southern European clone in Spain. Our results suggest that new S. 4,,12:i:- strains are continuously emerging from different S. Typhimurium strains via different genetic events, at least in swine products.
Except where otherwise noted, this item's license is described as 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).