Brucella

Brucella is a genus of Gram-negative bacteria, named after David Bruce (1855-1931). They are small (0.5 to 0.7 by 0.6 to 1.5 µm), nonencapsulated, flagellated, facultatively intracellular coccobacilli.

Brucella is the cause of brucellosis, which is a zoonosis transmitted by ingesting contaminated food (such as unpasteurized milk products), direct contact with an infected animal, or inhalation of aerosols. Transmission from human to human, for example through sexual intercourse or from mother to child, is exceedingly rare, but possible. Minimum infectious exposure is between 10 and 100 organisms.