Acute Haematogenous Osteomyelitis — Practice

A 4-year-old girl is brought with fever, refusal to bear weight on the left leg, and a tender warm swelling over the lower thigh. Aspiration of the metaphysis yields frank pus. A peripheral blood smear shown to you would most likely reveal neutrophilic leucocytosis with toxic granulation, and culture grows Gram-positive cocci in clusters. Which is the most likely causative organism in this acute haematogenous osteomyelitis?