Brucella is another strictly aerobic, Gram-negative coccobacillus which causes Brucellosis. This organism is sometimes carried by animals and only causes incidental infections in humans. The four species of this genus that can infect humans are named for the animal which they are most commonly found: B. abortus (cattle), B. suis (swine), B. melitensis (goats), B. canis (dogs). The cattle and dairy industries seem to be the primary source of infection in the United States. Brucella can enter the body via the skin, respiratory tract, or digestive tract. Once there, this intracellular organism can enter the blood and the lymphatics where it multiplies inside phagocytes and eventually cause bacteremia (bacterial blood infiltration). Symptoms vary from patient to patient but can include high fever, chills, and sweating. Afflicted individuals are usually treated with streptomycin or erythromycin.
