Final answer:
The main adhesins of Listeria monocytogenes are ActA and listeriolysin O (LLO), with the former facilitating intracellular movement and cell-to-cell spread via actin polymerization and the latter enabling escape from vacuoles after entry into host cells. Phagocyte receptors recognizing pathogen-associated molecular patterns are likely involved in attachment to host cells.
Step-by-step explanation:
The main adhesins of Listeria monocytogenes are important for its ability to cause listeriosis, a serious infection. One critical adhesin is the surface protein ActA, which induces polymerization of host actin, enabling the bacterium to produce actin tails for intracellular movement and cell-to-cell spread. Another important factor is the listeriolysin O (LLO), encoded by the gene hyl, which allows Listeria to escape from vacuoles after entering host cells.
Upon entry, Listeria can hijack the host cell's cytoskeleton components for its own benefit. The receptors for Listeria attachment are typically found on the intestinal epithelial cells' surface, and phagocyte receptors that recognize pathogen-associated molecular patterns may also play a role in initial attachment.