About this Research Topic
Brucellae are Gram-negative, facultative, intracellular bacteria that can infect humans and many species of animals. Brucellosis is an economically important disease in production animals worldwide causing abortion and infertility. Human brucellosis has always been associated with an animal reservoir of Brucella spp. and transmission occurs mainly via the food chain, in particular through dairy products, or via direct contact with diseased animals. The genus Brucella has traditionally been classified into six species, according to their preferential animal host, of which the most pathogenic for humans are B. melitensis, B. suis, and B. abortus. The genus Brucella has been further expanded with a set of new species discovered from the 1990s mainly from wildlife and including marine mammal species.
The genus Brucella belongs to the family Brucellaceae within the order Rhizobiales of the class Alphaproteobacteria. The closest phylogenetic neighbour of the genus Brucella is the genus Ochrobactrum, containing saprophytes that occasionally infect humans. Species belonging to the genus Brucella are genetically closely related (more than 90% DNA relatedness) which, from a genomic point of view, makes the genus monospecific. Although already proposed in 1985 that Brucella species should be grouped as biovars of a single species, this concept has not been widely supported by the scientific community. The discovery of new atypical species that are genomically more distant from the traditional species, and often initially misidentified phenotypically as Ochrobactrum spp., raises again questions about the species definition of strains belonging to the genus Brucella and the borderline between the genera Brucella and Ochrobactrum. In addition, pathogenesis of these new species for humans or livestock is currently unknown. Comparative genomics has provided insight into the evolutionary history of species belonging to the genus Brucella but has not yet facilitated identification of the underlying mechanisms involved in host preference or diseases caused in their respective hosts.
In this Research Topic, we encourage the submission of original research reports, opinions, perspectives, reviews and mini reviews that may further understanding of the evolutionary history of the genus Brucella and closely related genera such as Ochrobactrum through pathogenomic approaches. We also encourage submission of reports dealing with the development of new molecular detection or identification methods based on comparative genomics of the genus Brucella.
Keywords: brucella, bacteria, disease, Brucellae, pathogenomics
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