An adolescent client with non-union of a comminuted fracture of the tibia is admitted with osteomyelitis. The healthcare provider collects bone aspirate specimens for culture and sensitivity and applies a cast to the adolescent's lower leg. Which action should the nurse implement next?

A. Begin parenteral antibiotic therapy. This is the correct answer. Osteomyelitis is a serious bone infection that requires prompt and aggressive antibiotic therapy to prevent further complications and promote healing. B. Administer antiemetic agents. Antiemetic agents may be necessary if the client is experiencing nausea or vomiting, but this is not the priority action. C. Provide a high-calorie, high-protein diet. While nutritional support is important for healing, initiating antibiotic therapy to address the infection takes precedence. D. Bivalve the cast for distal compromise. Bivalving the cast might be necessary if there is evidence of compartment syndrome or impaired circulation, but there is no indication from the question that such a complication is present at this time.