Review Question - QID 213213

A 35-year-old female presents to the clinic for a red rash over her right thigh for the past 2 days. She reports a bug bite at the area a couple of days ago when she was hiking. It became itchy shortly after and she has been scratching the area ever since. A physical examination demonstrates a clearly-demarcated, erythematous area that is warm and tender upon palpation (Figure A). She is subsequently started on oral amoxicillin. During her follow-up appointment, she reports initial improvement, but that the rash is persisting. A culture of the skin lesion is positive for methicillin-sensitive Staphylococcal aureus (MSSA). She is started on nafcillin. What characteristic of this drug allows for more targeted treatment of this patient’s condition?