Characterisation of the genetic diversity of Brucella by multilocus sequencing

<p>Abstract</p> <p>Background</p> <p><it>Brucella </it>species include economically important zoonotic pathogens that can infect a wide range of animals. There are currently six classically recognised species of <it>Brucella </it>although, as yet unnamed, isolates from various marine mammal species have been reported. In order to investigate genetic relationships within the group and identify potential diagnostic markers we have sequenced multiple genetic loci from a large sample of <it>Brucella </it>isolates representing the known diversity of the genus.</p> <p>Results</p> <p>Nine discrete genomic loci corresponding to 4,396 bp of sequence were examined from 160 <it>Brucella </it>isolates. By assigning each distinct allele at a locus an arbitrary numerical designation the population was found to represent 27 distinct sequence types (STs). Diversity at each locus ranged from 1.03–2.45% while overall genetic diversity equated to 1.5%. Most loci examined represent housekeeping gene loci and, in all but one case, the ratio of non-synonymous to synonymous change was substantially <1. Analysis of linkage equilibrium between loci indicated a strongly clonal overall population structure. Concatenated sequence data were used to construct an unrooted neighbour-joining tree representing the relationships between STs. This shows that four previously characterized classical <it>Brucella </it>species, <it>B. abortus</it>, <it>B. melitensis</it>, <it>B. ovis </it>and <it>B. neotomae </it>correspond to well-separated clusters. With the exception of biovar 5, <it>B. suis </it>isolates cluster together, although they form a more diverse group than other classical species with a number of distinct STs corresponding to the remaining four biovars. <it>B. canis </it>isolates are located on the same branch very closely related to, but distinguishable from, <it>B. suis </it>biovar 3 and 4 isolates. Marine mammal isolates represent a distinct, though rather weakly supported, cluster within which individual STs display one of three clear host preferences.</p> <p>Conclusion</p> <p>The sequence database provides a powerful dataset for addressing ongoing controversies in <it>Brucella </it>taxonomy and a tool for unambiguously placing atypical, phenotypically discordant or newly emerging <it>Brucella </it>isolates. Furthermore, by using the phylogenetic backbone described here, robust and rationally selected markers for use in diagnostic assay development can be identified.</p

ATP-Binding Cassette Systems of Brucella

Brucellosis is a prevalent zoonotic disease and is endemic in the Middle East, South America, and other areas of the world. In this study, complete inventories of putative functional ABC systems of five Brucella species have been compiled and compared. ABC systems of Brucella melitensis 16M, Brucella abortus 9-941, Brucella canis RM6/66, Brucella suis 1330, and Brucella ovis 63/290 were identified and aligned. High numbers of ABC systems, particularly nutrient importers, were found in all Brucella species. However, differences in the total numbers of ABC systems were identified (B. melitensis, 79; B. suis, 72; B. abortus 64; B. canis, 74; B. ovis, 59) as well as specific differences in the functional ABC systems of the Brucella species. Since B. ovis is not known to cause human brucellosis, functional ABC systems absent in the B. ovis genome may represent virulence factors in human brucellosis

Rapid identification of Brucella isolates to the species level by real time PCR based single nucleotide polymorphism (SNP) analysis

<p>Abstract</p> <p>Background</p> <p>Brucellosis, caused by members of the genus <it>Brucella</it>, remains one of the world's major zoonotic diseases. Six species have classically been recognised within the family <it>Brucella </it>largely based on a combination of classical microbiology and host specificity, although more recently additional isolations of novel <it>Brucella </it>have been reported from various marine mammals and voles. Classical identification to species level is based on a biotyping approach that is lengthy, requires extensive and hazardous culturing and can be difficult to interpret. Here we describe a simple and rapid approach to identification of <it>Brucella </it>isolates to the species level based on real-time PCR analysis of species-specific single nucleotide polymorphisms (SNPs) that were identified following a robust and extensive phylogenetic analysis of the genus.</p> <p>Results</p> <p>Seven pairs of short sequence Minor Groove Binding (MGB) probes were designed corresponding to SNPs shown to possess an allele specific for each of the six classical <it>Brucella </it>spp and the marine mammal <it>Brucella</it>. Assays were optimised to identical reaction parameters in order to give a multiple outcome assay that can differentiate all the classical species and <it>Brucella </it>isolated from marine mammals. The scope of the assay was confirmed by testing of over 300 isolates of <it>Brucella</it>, all of which typed as predicted when compared to other phenotypic and genotypic approaches. The assay is sensitive being capable of detecting and differentiating down to 15 genome equivalents. We further describe the design and testing of assays based on three additional SNPs located within the 16S rRNA gene that ensure positive discrimination of <it>Brucella </it>from close phylogenetic relatives on the same platform.</p> <p>Conclusion</p> <p>The multiple-outcome assay described represents a new tool for the rapid, simple and unambiguous characterisation of <it>Brucella </it>to the species level. Furthermore, being based on a robust phylogenetic framework, the assay provides a platform that can readily be extended in the future to incorporate newly identified <it>Brucella </it>groups, to further type at the subspecies level, or to include markers for additional useful characteristics.</p

Brucellosis in ruminants and pastoralists in Borena, Southern Ethiopia

Funder: Biotechnology and Biological Sciences Research Council; funder-id: http://dx.doi.org/10.13039/501100000268; Grant(s): ref: BB/L018977/1Brucellosis is a bacterial zoonotic disease that has important veterinary and public health consequences as well as economic impact in sub Saharan Africa including Ethiopia. A cross-sectional study was conducted in four selected districts of Borena Pastoral setting in Southern Ethiopia from October 2017 to February 2018 to estimate the prevalence of brucellosis and assess associated risk factors in cattle, sheep, goats and occupationally associated humans. A total of 750 cattle, 882 sheep and goats and 341 human subjects were screened for evidence of brucellosis using the Rose Bengal Test (RBT) with positive results confirmed by Competitive-ELISA(c-ELISA). Structured questionnaires were used for collection of metadata from individual animals, herders and animal attendants to test the association between explanatory and outcome variables. The overall animal level prevalence was 2.4% (95% confidence interval, CI: 1.4–3.7) in cattle, 3.2% (95% CI: 2.1–4.6) in sheep and goats, and 2.6% (95% CI: 1.2–5) in humans occupationally linked to livestock production systems. Herd size, parity, and history of abortion were risk factors associated with Brucella seropositivity (P<0.05) in cattle whereas in sheep and goats the results showed that district, age group, flock size, and history of abortion were significantly associated risk factors with Brucella seropositivity (P<0.05). Assisting calving and presence of seropositive animals in a household (P<0.05) were significantly associated with Brucella seropositivity in humans. Evidence of brucellosis in various animal species and the associated human population illustrates the need for a coordinated One Health approach to controlling brucellosis so as to improve public health and livestock productivity

Marine Mammal Brucella Genotype Associated with Zoonotic Infection

Marine Mammal Brucella Genotype Associated with Zoonotic Infectio

Натечные карбонатные новообразования набережной реки Туры: особенности строения и процессы формирования

International audienc

First isolation of Brucella pinnipedialis and detection of Brucella antibodies from bearded seals Erignathus barbartus

Brucella species infecting marine mammals was first reported in 1994 and in the years since has been documented in various species of pinnipeds and cetaceans. While these reports have included species that inhabit Arctic waters, the few available studies on bearded seals Erignathus barbatus have failed to detect Brucella infection to date. We report the first isolation of Brucella pinnipedialis from a bearded seal. The isolate was recovered from the mesenteric lymph node of a bearded seal that stranded in Scotland and typed as ST24, a sequence type associated typically with pinnipeds. Furthermore, serological studies of free-ranging bearded seals in their native waters detected antibodies to Brucella in seals from the Chukchi Sea (1990-2011; 19%) and Svalbard (1995-2007; 8%), whereas no antibodies were detected in bearded seals from the Bering Sea or Bering Strait or from captive bearded seals