Brucella abortus

Brucella abortus

Brucella spp. under a microscope

Brucella abortus is a species of the genus Brucella, which is a group of Gram-negative bacteria. These bacteria are known to cause brucellosis, a zoonotic infection that affects various animal species and can be transmitted to humans. Brucella abortus primarily affects cattle, leading to reproductive issues such as abortion, which is reflected in its name.

Characteristics

Brucella abortus is a small, non-motile, facultative intracellular coccobacillus. It is an aerobic organism that does not form spores. The bacteria are characterized by their ability to survive and replicate within host cells, particularly macrophages. This intracellular lifestyle allows them to evade the host's immune system and establish chronic infections.

Pathogenesis

The pathogenesis of Brucella abortus involves the bacteria entering the host through mucosal surfaces or skin abrasions. Once inside the host, they are phagocytosed by macrophages and other phagocytic cells. Instead of being destroyed, Brucella abortus can survive and replicate within these cells by inhibiting the fusion of phagosomes with lysosomes. This allows the bacteria to persist in the host and cause chronic infection.

Clinical Manifestations

In cattle, Brucella abortus infection leads to reproductive problems, including abortion, retained placenta, and infertility. Infected animals may also exhibit decreased milk production and arthritis. In humans, brucellosis caused by Brucella abortus can result in undulant fever, fatigue, joint pain, and other systemic symptoms.

Diagnosis

Diagnosis of Brucella abortus infection involves serological tests, such as the Rose Bengal test, and culture methods to isolate the bacteria. Molecular techniques, such as polymerase chain reaction (PCR), are also used for more accurate identification.

Treatment and Prevention

Treatment of brucellosis in humans typically involves a combination of antibiotics, such as doxycycline and rifampin, for an extended period. In cattle, control measures include vaccination with the Brucella abortus strain 19 or RB51 vaccines, as well as implementing biosecurity measures to prevent the spread of the bacteria.

Related Pages

• Brucellosis
• Zoonosis
• Cattle
• Antibiotics