B rucella

Abstract

Bru.cel'la . L. dim. ending ‐ ella ; N.L. fem. n. Brucella named after Sir David Bruce, who first recognized the organism causing undulant (Malta) fever. Proteobacteria / Alphaproteobacteria / Rhizobiales / Brucellaceae / Brucella Brucella represents an expanding genus of potentially zoonotic pathogens originally associated predominantly with terrestrial livestock and companion animals but, in recent years, new species have been described particularly from the marine environment and wildlife sources. Highly genetically conserved. Most closely related to Ochrobactrum . Some newer species have been described as “atypical” based on phenotypes or genotypes that diverge from classically described species. Many species are facultatively intracellular pathogens of animals and/or humans with species and some biovars showing distinct host tropisms. Mostly isolated from clinical specimens or contaminated food products with many clinical strains requiring complex growth media and supplementary CO 2 for growth, especially on primary isolation. Colonies on serum‐dextrose agar or other clear media are transparent, raised, convex, with an entire edge and a smooth, shiny surface appearing in a pale honey color under transmitted light. Atypical species may present as mucoid spreading colonies. Growth of many species is improved by serum or blood. Optimal temperature for growth 37°C. Optimal pH for growth 6.6–7.4. Catalase and urease positive. Oxidase variable. Gram negative non‐motile cocci, coccobacilli or short rods. No capsule produced. Aerobic, possessing a respiratory type of metabolism and having a cytochrome‐based electron transport system with oxygen or nitrate as the terminal electron acceptor. Chemoorganotrophic. The genome typically comprises two circular chromosomes. DNA G + C content (mol%) : 57.1–59. Type species : Brucella melitensis (Hughes 1893) Meyer and Shaw 1920, 179 AL ( Streptococcus melitensis Hughes 1893, 235).

Taxonomic Organization of the Family Brucellaceae Based on a Phylogenomic Approach

“…Despite this lack of diversity, the phylogenetic relationship between species was extensively investigated using various genetic tools and more recently with the availability of whole-genome sequences, and are now well resolved (Foster et al, 2009;Wattam et al, 2014, Al Dahouk et al, 2017. The current classification includes 12 Brucella species commonly classified as 'classical' or 'atypical' , depending on their phenotypical characteristics and their phylogenetic relationships (Scholz et al, 2018).…”

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

“…The type genus Brucella (Scholz et al, 2018) contains the causative agents of brucellosis, which remains one of the most important zoonotic diseases globally, with more than 500,000 new cases reported each year (Pappas et al, 2006). For several decades the genus Brucella was described as consisting of six "classical" species (B. abortus, B. melitensis, B. ovis, B. suis, B. canis, and B. neotomae), with well characterized mammalian host preferences (Corbel, 2006).…”

Brucellosis in Ethiopia: A comprehensive review of literature from the year 2000–2020 and the way forward

“…The disease is characterized by reproductive disorders such as abortion, stillbirth and birth of weak offspring in females and orchitis and epididymitis in male animals causing transient or permanent infertility (Constable et al., 2017). The genus Brucella currently comprises six classical species primarily affecting domestic animals and rodents including B. melitensis of small ruminants, B. abortus of cattle, B. suis of pigs and hares, B. ovis of small ruminants, B. canis of dogs and B. neotomae of desert wood rats; and six novel species identified from marine mammals ( B. penippedialis and B. ceti ), red foxes ( B. vulpes ), baboons ( B. papionis ), a human breast implant ( B. inopinata ) and rodents ( B. microti ) (Scholz et al., 2018). While brucellae are host‐adapted to preferred hosts, they are capable of infecting other species (Pappas, 2010).…”