A 20-year-old woman shows thick, white vaginal discharge and erythema. What is the appropriate treatment mechanism for her condition?

• A. Prevention of cross-linking of B-glucans in the cell wall
• B. Pore formation in the fungal cell membrane
• C. Inhibition of DNA and RNA synthesis
• D. Inhibition of cytochrome P450-dependent demethylation reaction

Answer: (D)

The symptoms described in the scenario—thick, white vaginal discharge and erythema—are suggestive of a yeast infection, commonly caused by Candida species. The appropriate treatment mechanism for this condition primarily involves targeting the underlying fungal infection.

The correct answer involves the inhibition of cytochrome P450-dependent demethylation, which is the mechanism of action of azole antifungals, such as fluconazole. These agents work by interfering with the synthesis of ergosterol, an essential component of the fungal cell membrane. By inhibiting the cytochrome P450 enzymes, they prevent the demethylation of lanosterol, leading to depletion of ergosterol and disrupting the integrity of the fungal cell membrane. This ultimately results in cell death and resolution of the infection.

The other treatment mechanisms mentioned do not apply to the primary treatment of a vaginal yeast infection. For example, prevention of cross-linking of β-glucans is the mechanism of action for echinocandins, which are not first-line treatments for Candida infections. Pore formation in the fungal cell membrane relates to agents like nystatin and amphotericin B but is not the most relevant for this case. Inhibition of DNA and RNA synthesis typically pertains to other