Question

Key Characteristics of L. monocytogenes

Catalase---
Esculin----
CAMP---
Motility on wet mount---
a) Positive, Negative, Positive, Positive
b) Negative, Positive, Positive, Negative
c) Positive, Positive, Positive, Negative
d) Negative, Positive, Negative, Positive

Answer 1

Key Characteristics of L. monocytogenes are b) Negative, Positive, Positive, Negative

Step-by-step explanation:

The correct combination of characteristics for *Listeria monocytogenes* is b) Negative, Positive, Positive, Negative.

- **Catalase:** L. monocytogenes is catalase-negative, meaning it does not produce catalase enzyme.

- **Esculin:** L. monocytogenes is esculin-positive. It hydrolyzes esculin in the presence of bile, leading to a characteristic blackening of the medium.

- **CAMP Test:** L. monocytogenes shows a positive reaction in the CAMP test. The CAMP factor produced by L. monocytogenes enhances the hemolytic activity of *Streptococcus agalactiae* (Group B Streptococcus) when the two are streaked perpendicularly on a blood agar plate.

- **Motility on Wet Mount:** L. monocytogenes is motile, exhibiting a characteristic tumbling or darting motility under wet mount examination.

Understanding these key characteristics is essential for the identification of *Listeria monocytogenes*, a bacterium known for causing the foodborne illness listeriosis. Differentiating bacterial species based on such traits is a fundamental aspect of clinical microbiology and plays a crucial role in diagnosing infections and implementing appropriate treatments.