Question

Shigella flexneri is:

• A. gram-negative, nonmotile, facultatively anaerobic, non-spore-forming bacillus
• B. gram-negative, motile, facultatively anaerobic, non-spore-forming bacillus
• C. gram-negative, nonmotile, facultatively aerobic, non-spore-forming bacillus
• D. gram-negative, nonmotile, facultatively anaerobic, spore-forming bacillus

Hint:

Shigella flexneri is one of the causative agents of dysentery, leading to severe intestinal illness. It is often transmitted via contaminated water or food.

Answer 1

The Correct Option is A

Shigella flexneri is a gram-negative bacterium that is nonmotile and facultatively anaerobic, meaning it can survive with or without oxygen. It does not form spores, which is a characteristic of some other types of bacteria. The key traits that define Shigella flexneri include:
- Gram-negative: The bacteria have a thin peptidoglycan layer and an outer membrane.
- Nonmotile: Unlike some other species of Shigella, flexneri does not have flagella and cannot move.
- Facultatively anaerobic: It can live in both oxygen-rich and oxygen-poor environments.
- Non-spore-forming: Unlike some bacteria, Shigella flexneri does not produce spores to survive harsh conditions.
- Option (2) is incorrect because Shigella flexneri is nonmotile, not motile.
- Option (3) is incorrect because it is facultatively anaerobic, not facultatively aerobic.
- Option (4) is incorrect because Shigella flexneri does not form spores.
Thus, the correct answer is option (1): gram-negative, nonmotile, facultatively anaerobic, non-spore-forming bacillus.