A 6-year-old girl from Delhi presents with her father with a 5-day history of painful, fluid-filled blisters on her legs that are preceded by small pustules. The blisters rupture easily, leaving erosions with a thin, transparent crust. She has mild fever (38.2°C). On examination, there are flaccid bullae with clear fluid. Nikolsky sign is negative. Culture of blister fluid grows methicillin-resistant *Staphylococcus aureus* (MRSA). Which of the following is the most appropriate antibiotic choice?