**Core Concept**
Ampitrichous flagella refer to a type of flagella arrangement found in certain bacteria, where two flagella are attached to the cell at opposite ends. This unique flagella arrangement is characteristic of specific bacterial species, and it plays a crucial role in their motility and survival.

**Why the Correct Answer is Right**
Alcaligenes faecalis, a gram-negative, rod-shaped bacterium, is known to possess ampitrichous flagella. The presence of these flagella enables A. faecalis to move effectively in its environment, allowing it to colonize new areas and evade host immune responses. The ampitrichous flagella arrangement in A. faecalis is thought to be an adaptation for its aquatic and environmental habitats. This unique flagella arrangement is a key characteristic distinguishing A. faecalis from other bacterial species.

**Why Each Wrong Option is Incorrect**
**Option A:** Vibrio cholerae, the causative agent of cholera, possesses a single polar flagellum, not ampitrichous flagella. Its flagellum is located at one end of the cell, facilitating its motility in the human gut.

**Option B:** Spirillum minus, a gram-negative, spiral-shaped bacterium, has a single polar flagellum, not ampitrichous flagella. Its flagellum is located at one end of the cell, enabling it to move effectively in its environment.

**Option C:** Listeria, a gram-positive, rod-shaped bacterium, possesses a single peritrichous flagellum, not ampitrichous flagella. Its flagellum is located all over the cell surface, facilitating its motility in various environments.

**Clinical Pearl / High-Yield Fact**
Ampitrichous flagella are a distinctive feature of Alcaligenes faecalis, making it an important species to recognize in microbiological diagnoses. This unique flagella arrangement can be a key identifying characteristic in the identification of this bacterium.

**✓ Correct Answer: D. Alcaligenes faecalis**