A 48-year-old man is brought to the emergency department with fever, severe headache, neck stiffness, and altered mental status. He has a history of chronic sinusitis. Lumbar puncture reveals: •Elevated WBC count (neutrophil predominance) •Low glucose •Elevated protein •Gram stain: Gram-positive diplococci Which of the following adjunctive therapies has been shown to improve survival and reduce the risk of hearing loss in this patient?
