Listeria monocytogenes

Definition

Listeria monocytogenes is a Gram-positive, rod-shaped bacterium responsible for the infection listeriosis. It is known for its ability to thrive in refrigerated conditions and can cause severe illness in immunocompromised individuals.

5 Must Know Facts For Your Next Test

1. Listeria monocytogenes can grow at temperatures as low as 0°C, making it a concern in refrigerated foods.
2. It is a facultative anaerobe, meaning it can grow in both oxygen-rich and oxygen-poor environments.
3. Listeriosis primarily affects pregnant women, newborns, older adults, and those with weakened immune systems.
4. The bacterium uses actin-based motility to move within host cells and spread to adjacent cells.
5. Symptoms of listeriosis include fever, muscle aches, and sometimes gastrointestinal symptoms; severe cases can lead to meningitis or encephalitis.

Review Questions

• What type of environment does Listeria monocytogenes thrive in?
• Which populations are most at risk for severe illness from Listeria monocytogenes?
• How does Listeria monocytogenes spread within the host organism?

Related terms

Facultative Anaerobe: An organism that can survive with or without oxygen.

Meningitis: Inflammation of the protective membranes covering the brain and spinal cord.

Actin-based Motility: A mechanism used by some bacteria to move within and between host cells using the host's actin filaments.