Assessment ofPasteurella multocidaA Lipopolysaccharide, as an Adhesin in an In Vitro Model of Rabbit Respiratory Epithelium

Abstract

The role of theP. multocidalipopolysaccharide (LPS) as a putative adhesin during the early stages of infection with this bacterium in the respiratory epithelium of rabbits was investigated. By light microscopy and double enzyme labeling of nasal septa tissues, the amount of bacteria attached to the respiratory epithelium and the amount of LPS present in goblet cells at different experimental times were estimated. Transmission electron microscopy (TEM) and LPS labeling with colloidal gold particles were also used to determine the exact location of LPS in the cells. Septa that were challenged with LPS ofP. multocidaand 30 minutes later withP. multocidashowed more adherent bacteria and more severe lesions than the other treatments. Free LPS was observed in the lumen of the nasal septum, forming bilamellar structures and adhering to the cilia, microvilli, cytoplasmic membrane, and cytoplasm of epithelial ciliated and goblet cells. The above findings suggest thatP. multocidaLPS plays an important role in the process of bacterial adhesion and that it has the ability of being internalized into host cells.