A 25 year old man with a history of injection drug use is admitted in hospital with evidence of furuncles along his left forearm. On examination, he is febrile with a temperature of 38.5°C, heart rate of 120 bpm, and blood pressure of 120/70 mmHg. Examination of the forearm reveals a focal 3x3cm area with a cluster of boils surrounded by erythema. His left forearm is warm on palpation, tender, and purulent drainage is expressed.
Vancomycin is initiated empirically and he undergoes an incision and drainage (I&D). There is no evidence of necrotizing fasciitis or metastatic foci. On admission, his leukocyte count is 18 x109/L and his creatinine is normal. Blood cultures obtained prior to administration of antimicrobials are negative for growth. A wound culture from his I&D shows gram-positive cocci in clusters, later identified as methicillin-resistant Staphylococcus aureus (MRSA).
On day 3 of his admission, he is afebrile and has clinically defervesced with improvement in erythema and warmth. You plan to switch him to oral antimicrobial therapy.