A 40-year-old intravenous drug user presents to the emergency depament with a 2 days history of right knee pain with associated swelling and erythema. The patient is febrile with a holosystolic murmur at the right lower sternal border. Complete blood count reveals leukocytosis. Blood and synol fluid cultures are sent, and broad-spectrum antibiotics are staed. Synol fluid analysis is pending. What is the most likely pathogen causing these symptoms