New insights into phylogeography of worldwide Brucella canis isolates by comparative genomics-based approaches: focus on Brazil

Acácia Ferreira Vicente,Mateus Souza Ribeiro Mioni,Guillaume Girault,Jane Megid,Virginie Mick,Yannick Corde,Maryne Jay,Lara Borges Keid

doi:10.1186/s12864-018-5001-6

Acácia Ferreira Vicente, Mateus Souza Ribeiro Mioni + Show 6 more

Open Access

https://doi.org/10.1186/s12864-018-5001-6

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Abstract

BackgroundCanine brucellosis, due to Brucella canis, is a worldwide zoonosis that remains endemic in South America, including Brazil. Implementation of powerful whole-genome sequencing approaches allowed exploring the Brucella genus considered as monomorphic, with, to date, more than 500 genomes available in public databases. Nevertheless, with under-representation of B. canis genomes −only twenty complete or draft genomes−, lack of knowledge about this species is still considerable. This report describes a comparative genomics-based phylogeographic investigation of 53 B. canis strains, including 28 isolates paired-end sequenced in this work.ResultsObtained results allow identifying a SNP panel species-specific to B. canis of 1086 nucleotides. In addition, high-resolution analyses assess the epidemiological relationship between worldwide isolates. Our findings show worldwide strains are distributed among 2 distinct lineages. One of them seems to be specific to South American strains, including Brazil. B. canis South American strains may be identified by a SNP panel of 15 nucleotides, whereas a 22 SNP panel is sufficient to define contamination origin from Brazil. These results lead to the proposal of a possible spread route for dog brucellosis through South America. Additionally, whole-genome analyses highlight the remarkable genomic stability of B. canis strains over time and the sustainability of the infection in São Paulo over 12 year-period.ConclusionsSignificant increase of B. canis genomes available in public databases provides new insights into B. canis infection in South America, including Brazil, as well as in the world, and also offers new perspectives for the Brucella genus largo sensu.

Highlights

Canine brucellosis, due to Brucella canis, is a worldwide zoonosis that remains endemic in South America, including Brazil
Canine brucellosis is a worldwide zoonosis caused by Brucella canis [1,2,3]
WgSNP results showed too extreme in vivo genomic stability over time, e.g. two samples isolated in China (BCB018 and 118) [20, 21] with only 12 Single Nucleotide Polymorphism (SNP) difference in a 20 year-interval

Summary

Introduction

Due to Brucella canis, is a worldwide zoonosis that remains endemic in South America, including Brazil. Implementation of powerful whole-genome sequencing approaches allowed exploring the Brucella genus considered as monomorphic, with, to date, more than 500 genomes available in public databases. Canine brucellosis is a worldwide zoonosis caused by Brucella canis [1,2,3]. This bacterium is usually associated with dogs and occasionally causes brucellosis in humans [1]. B. canis infections, mainly diagnosed by serological methods and bacteriological evidence [5], remain endemic in South America, including Brazil with high dog population [3], raising public and animal health concerns. More than 500 Brucella genomes are available on public databases, B. canis is poorly represented with only 20 complete and draft genomes available [20,21,22,23,24,25]

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