Brucella spp. is a facultative intracellular coccobacillus. Intracellular survival in which cell type is important in the pathogenesis of brucellosis and lesion development?

Brucella spp. is a facultative intracellular coccobacillus. Intracellular survival in which cell type is important in the pathogenesis of brucellosis and lesion development?

• A. Neutrophils
• B. Lymphocytes
• C. Monocytes
• D. Erythrocytes

Answer: (C)

Brucella species rely on living inside monocytes/macrophages to establish infection and drive lesion formation. After entry, these bacteria survive and replicate within macrophage phagosomes, often by hindering phagosome-lysosome fusion and resisting killing. This intracellular niche lets Brucella disseminate through the reticuloendothelial system and cause granulomatous lesions in organs like the liver, spleen, and bone marrow. Because monocytes circulate and differentiate into tissue macrophages, this cellular habitat is what underpins both systemic spread and localized tissue damage. Neutrophils are more about rapid, short-term responses and extracellular killing, while erythrocytes and lymphocytes do not provide the replication niche Brucella needs.

Brucella species rely on living inside monocytes/macrophages to establish infection and drive lesion formation. After entry, these bacteria survive and replicate within macrophage phagosomes, often by hindering phagosome-lysosome fusion and resisting killing. This intracellular niche lets Brucella disseminate through the reticuloendothelial system and cause granulomatous lesions in organs like the liver, spleen, and bone marrow. Because monocytes circulate and differentiate into tissue macrophages, this cellular habitat is what underpins both systemic spread and localized tissue damage. Neutrophils are more about rapid, short-term responses and extracellular killing, while erythrocytes and lymphocytes do not provide the replication niche Brucella needs.