Biological sex influences susceptibility to Acinetobacter baumannii pneumonia in mice

Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced neutrophil and alveolar macrophage numbers compared to male mice. Depletion of either neutrophils or alveolar macrophages was important for bacterial clearance however, depletion of alveolar macrophages further exacerbated female susceptibility due to severe alterations in metabolic homoeostasis. RNA was extracted from lung homogenates of female and male mice depleted of alveolar macrophages following a 4 h infection with Acinetobacter baumannii