Genetic and Phenotypic Characterization of the Etiological Agent of Canine Orchiepididymitis Smooth Brucella sp. BCCN84.3

Abstract

Members of the genus Brucella cluster in two phylogenetic groups: classical and non-classical species. The former group is composed of Brucella species that cause disease in mammals, including humans. A Brucella species, labeled as Brucella sp. BCCN84.3, was isolated from the testes of a Saint Bernard dog suffering orchiepididymitis, in Costa Rica. Following standard microbiological methods, the bacterium was first defined as “ Brucella melitensis biovar 2.” Further molecular typing, identified the strain as an atypical “ Brucella suis .” Distinctive Brucella sp. BCCN84.3 markers, absent in other Brucella species and strains, were revealed by fatty acid methyl ester analysis, high resolution melting PCR and omp25 and omp2a/omp2b gene diversity. Analysis of multiple loci variable number of tandem repeats and whole genome sequencing demonstrated that this isolate was different from the currently described Brucella species. The smooth Brucella sp. BCCN84.3 clusters together with the classical Brucella clade and displays all the genes required for virulence. Brucella sp. BCCN84.3 is a species nova taxonomical entity displaying pathogenicity; therefore, relevant for differential diagnoses in the context of brucellosis. Considering the debate on the Brucella species concept, there is a need to describe the extant taxonomical entities of these pathogens in order to understand the dispersion and evolution.

Brucella Genomics: Macro and Micro Evolution

“…This strain displayed distinctive biochemical properties and a unique SDS-PAGE protein profile [ 82 ]. This isolate was initially identified under experts’ hands as B. melitensis biovar 2, afterward as an atypical B. suis [ 77 ]. MLVA-16, WGS, and detailed phenotypic characterization identified the Brucella sp.…”

“…MLVA-16, WGS, and detailed phenotypic characterization identified the Brucella sp. BCCN84.3 as distinct species, after 35 years of its isolation [ 77 ]. Due to their broader metabolic alternatives, non-classical Brucella isolates from humans were initially identified as Ochrobactrum spp.…”

“…A blue square highlights all Brucella species; the “classical” species are within the up left square. Modified from [ 77 ]. In Table S1 are the details of the strains and sequences used for the analysis.…”

Application of Whole Genome Sequencing and Pan-Family Multi-Locus Sequence Analysis to Characterize Relationships Within the Family Brucellaceae

“…Subsequently, additional species have been described, with the genus expanding to include B. pinnipedialis and B. ceti isolated from marine mammals ( Foster et al, 2007 ), B. microti from voles ( Scholz et al, 2008b ), B. inopinata isolated from a human infection ( Scholz et al, 2010 ), B. papionis from baboons ( Whatmore et al, 2014 ) and B. vulpis , isolated from foxes ( Scholz et al, 2016a ). Additionally, a number of novel atypical strains from human and other mammalian hosts have been described, but await formal classification ( Tiller et al, 2010a , b ; Guzmán-Verri et al, 2019 ). These species and strains reflect an ongoing expansion of the known host range and genetic diversity of the genus.…”

Investigation of small ruminant brucellosis among smallholder farms: The missing link in control programmes of endemic areas

“…Different studies demonstrated that the low economical profit of small farms, limitation of veterinary support and minimal education/training of farmers may contribute to the persistence of risk factors (Asinamai et al., 2018; Beauvais et al., 2016; Coelho et al., 2019). Furthermore, as shown in the current study, B. melitensis biovar 2 can infect dogs and circulates between farms, playing an important role in the human contamination (Forbes, 1990; Guzmán‐Verri et al, 2019; Rezaei‐Sadaghiani et al., 1996). The infection of dogs with B. suis , B. melitensis and B. abortus has been shown in both field and experimental studies.…”