The only species in the genus Hafnia is Hafnia alvei.

The only species in the genus Hafnia is Hafnia alvei.

• A. Hafnia alvei
• B. Hafnia gergoviae
• C. Hafnia tarda
• D. Hafnia ruckeri

Answer: (A)

The genus Hafnia is monotypic, meaning it contains only one valid species. In current taxonomy, Hafnia alvei is the sole recognized Hafnia species, while the other names listed (gergoviae, tarda, ruckeri) are not accepted as separate Hafnia species today—they are historical classifications or have been reassigned. That’s why the statement is correct: Hafnia alvei is the only species in the genus Hafnia. In practice, Hafnia alvei is a Gram-negative, enteric bacterium that can be an opportunistic pathogen, but the key point for this question is its status as the sole Hafnia species.

The genus Hafnia is monotypic, meaning it contains only one valid species. In current taxonomy, Hafnia alvei is the sole recognized Hafnia species, while the other names listed (gergoviae, tarda, ruckeri) are not accepted as separate Hafnia species today—they are historical classifications or have been reassigned. That’s why the statement is correct: Hafnia alvei is the only species in the genus Hafnia. In practice, Hafnia alvei is a Gram-negative, enteric bacterium that can be an opportunistic pathogen, but the key point for this question is its status as the sole Hafnia species.