Which of the following will differentiate Listeria monocytogenes from the corynebacteria?

Which of the following will differentiate Listeria monocytogenes from the corynebacteria?

• A. Nonmotile and salicin negative
• B. Motile and salicin positive
• C. Nitrate positive and sucrose positive
• D. Motile and urease negative

Answer: (A)

Listeria monocytogenes can be differentiated from corynebacteria through its motility and biochemical characteristics. The key to this differentiation is understanding that Listeria monocytogenes is motile at 25°C, often described as tumbling motility, whereas corynebacteria are typically nonmotile. Additionally, Listeria monocytogenes is known to be positive for the fermentation of salicin, while many corynebacteria do not ferment salicin. Therefore, if a bacterium is nonmotile and does not ferment salicin, it is likely part of the corynebacteria group. In summary, recognizing that Listeria monocytogenes is motile and can ferment salicin helps in distinguishing it from the nonmotile, salicin-negative nature of corynebacteria, making the characteristics of being nonmotile and salicin negative significant for differentiation.

Listeria monocytogenes can be differentiated from corynebacteria through its motility and biochemical characteristics. The key to this differentiation is understanding that Listeria monocytogenes is motile at 25°C, often described as tumbling motility, whereas corynebacteria are typically nonmotile.

Additionally, Listeria monocytogenes is known to be positive for the fermentation of salicin, while many corynebacteria do not ferment salicin. Therefore, if a bacterium is nonmotile and does not ferment salicin, it is likely part of the corynebacteria group.

In summary, recognizing that Listeria monocytogenes is motile and can ferment salicin helps in distinguishing it from the nonmotile, salicin-negative nature of corynebacteria, making the characteristics of being nonmotile and salicin negative significant for differentiation.