Answer :
Final answer:
Listeria monocytogenes is a gram-positive rod-shaped bacterium that causes listeriosis, a foodborne illness. It has unique characteristics that allow it to survive in different environments and cause infections. Listeria's pathogenicity is due to specific virulence genes that enable it to invade and spread within host cells.
Explanation:
Listeria monocytogenes is a gram-positive rod-shaped bacterium that causes listeriosis, a foodborne illness. It is nonencapsulated, nonsporulating, and has the ability to grow at refrigeration temperatures and tolerate high concentrations of salt. Listeria can be found in soil, water, and food, especially meat, fish, and dairy products. It is usually identified through cultivation of samples from a sterile site.
Listeria's pathogenicity is attributed to a cluster of virulence genes that enable it to invade host cells and spread without exiting into the extracellular compartment.
