Which statement describes a distinguishing growth characteristic of Listeria monocytogenes?

Which statement describes a distinguishing growth characteristic of Listeria monocytogenes?

• A. Is non-motile at room temperature.
• B. Requires aerobic conditions.
• C. Grows at refrigeration temperatures (4°C); tumbling motility at room temperature; facultative intracellular organism.
• D. Does not grow at 4°C.

Answer: (C)

Listeria monocytogenes is notable for a combination of growth traits: it can multiply at refrigeration temperatures (4°C), it shows tumbling motility at room temperature, and it is a facultative intracellular organism. This means it can grow outside cells as well as inside host cells, which is a key feature in its pathogenic behavior and in food safety concerns. Growing at 4°C explains why it can contaminate and multiply in refrigerated foods, a property that many other pathogens do not have. Tumbling motility at room temperature reflects its flagellar activity when not inside cells, a characteristic used to distinguish it from non-m motile organisms. Being facultative intracellular accounts for its ability to invade and survive within host cells, contributing to its virulence and intracellular spread. The other statements don’t fit because Listeria is motile at room temperature (not non-motile), it does not require strictly aerobic conditions (it is facultative and can grow under various oxygen levels), and it does grow at 4°C (so “does not grow at 4°C” is incorrect).

Listeria monocytogenes is notable for a combination of growth traits: it can multiply at refrigeration temperatures (4°C), it shows tumbling motility at room temperature, and it is a facultative intracellular organism. This means it can grow outside cells as well as inside host cells, which is a key feature in its pathogenic behavior and in food safety concerns.

Growing at 4°C explains why it can contaminate and multiply in refrigerated foods, a property that many other pathogens do not have. Tumbling motility at room temperature reflects its flagellar activity when not inside cells, a characteristic used to distinguish it from non-m motile organisms. Being facultative intracellular accounts for its ability to invade and survive within host cells, contributing to its virulence and intracellular spread.

The other statements don’t fit because Listeria is motile at room temperature (not non-motile), it does not require strictly aerobic conditions (it is facultative and can grow under various oxygen levels), and it does grow at 4°C (so “does not grow at 4°C” is incorrect).