| Summary: | The infection of pregnant animals and women by <i>Coxiella burnetii</i>, an intracellular bacterium, compromises both maternal health and foetal development. The placenta is targeted by <i>C. burnetii,</i> as demonstrated by bacteriological and histological evidence. It now appears that placental strains of <i>C.</i> <i>burnetii</i> are highly virulent compared to reference strains and that placental injury involves different types of placental cells. Trophoblasts, the major placental cells, are largely infected by C. <i>burnetii</i> and may represent a replicating niche for the bacteria. The placenta also contains numerous immune cells, including macrophages, dendritic cells, and mast cells. Placental macrophages are infected and activated by <i>C. burnetii</i> in an unusual way of M1 polarisation associated with bacterial elimination. Placental mast cells eliminate bacteria through a mechanism including the release of extracellular actin filaments and antimicrobial peptides. In contrast, <i>C. burnetii</i> impairs the maturation of decidual dendritic cells, favouring bacterial pathogenicity. Our aim is to review <i>C. burnetii</i> infections of human placentas, paying special attention to both the action and function of the different cell types, immune cells, and trophoblasts targeted by <i>C. burnetii</i> in relation to foetal injury.
|
|---|
