The antifungal which has a bactericidal mode of action against dermatophyte infections in therapeutic doses is :
**Core Concept**
The question is testing the understanding of the antifungal mechanism of action, specifically the distinction between fungicidal and fungistatic effects in the context of treating dermatophyte infections.
**Why the Correct Answer is Right**
The correct answer is a fungicidal agent that targets dermatophytes by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes. In therapeutic doses, this agent is capable of killing dermatophyte cells, thereby exerting a bactericidal (note: fungicidal) effect. This is in contrast to fungistatic agents, which only inhibit fungal growth and do not kill the cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This antifungal is a fungistatic agent that inhibits the synthesis of ergosterol, but its mechanism is different from the correct answer. It is not bactericidal in therapeutic doses.
**Option B:** This option is incorrect because it is not an antifungal agent that targets dermatophytes. Its mechanism of action is unrelated to the treatment of dermatophyte infections.
**Option C:** This antifungal is a fungistatic agent that works by inhibiting the synthesis of a different component of the fungal cell wall. It is not bactericidal in therapeutic doses.
**Clinical Pearl / High-Yield Fact**
When treating dermatophyte infections, it is essential to choose an antifungal agent that is effective against the causative organism. The correct answer is a key example of a fungicidal agent that can be used to treat these infections.
**Correct Answer:** A. Griseofulvin