FN1 and susceptibility to pneumonia measurement: The Apr protease interferes with endothelial fibronectin and laminin, degrading cytokines and complement proteins [46], while alginate polysaccharide (AlgD) evades pulmonary phagocytosis and promotes bacterial resistance to antibiotics [47,48], and the Cif protein promotes the severity of infections in patients with cystic fibrosis and pneumonia [49].