A 4-Year-Old Girl Is Brought to the Emergency Department Because

A 4-year-old girl is brought to the emergency department because of chest pain for 3 hours. One week ago, she was admitted to the hospital for treatment of low-grade fever, malaise, and sore throat. The hospitalization was complicated by pharyngitis with pseudomembrane formation and severe cervical lymphadenopathy briefly requiring intubation. She has not received any routine childhood vaccinations. Serum studies show elevated cardiac troponins. An ECG shows diffuse T wave inversions and prolonged PR interval. Administration of which of the following at the time of her previous admission is most likely to have prevented this patient's cardiac symptoms?

A) Airway edema reduction with inhaled epinephrine
B) Antibiotics administration to kill bacteria within the bloodstream
C) Blunting the immune response with glucocorticoids
D) Preformed antibody administration to bind bacterial product
E) Vaccination with inactivated bacterial toxin