Listeria monocytogenes (G+)

Question 1

what shape does listeria monocytogenes have?

Answer 1

G+ rod

Question 2

where does listeria monocytogenes colonize?

Answer 2

intestinal tract of vertebrates, sewage, soil, and water

Question 3

how is listeria monocytogenes transmitted?

Answer 3

food borne pathogen:

• aided by its exceptional heat resistance (37C)
• can grow at refrigerator temps. (4C)

Question 4

what are the 2 types of motility of listeria monocytogenes?

Answer 4

1. peritrichous flagella

2. actin polymerization

Question 5

what can happen if you contract listeriosis?

Answer 5

• can result in systemic infections such as bacteremia and meningitis
• immunocompromised, elderly, and prego people more susceptible
• 5-10% of adults are asymptomatic carriers

Question 6

what are the virulence factors of Listeria?

Answer 6

• internalins: mediate adherance and invasion of cells
• listerolysin O: enables escape from vacuoles, responsible for Beta-hemolytic pattern
• phospholipases: also aid escape from vacuoules, movement thru cell via actin polymerization, can cross placenta

Question 7

where in the cell does listeria replicate?

Answer 7

cytoplasm

Question 8

how can contraction of listeria be prevented?

Answer 8

control of growth in the food supply

• avoid unpasteurized milk and juices
• pregnant and immunocompromised people are advised to avoid deli foods, raw meats and soft cheeses

Question 9

how is listeria treated?

Answer 9

• antibiotics are effective if diagnosed in time
• unfortunately, stillbirths and systemic infections in adults are usually the first signs of an outbreak
• can pass through the placenta