A 25-year-old man presents to the emergency room with several red, swollen, tender bite wounds on both arms that he stated occurred yesterday when he rescued his dog from a dogfight involving three other dogs, whose owner(s) is unknown. His right wrist and left elbow are also swollen and there is axillary lymphadenopathy on the left side. Gram stain of purulent material from the worst wound shows small gram-negative pleomorphic coccobacilli. The patient reports his last tetanus vaccination was 2 years ago. In addition to antibiotics, which of the following should be included in this patient's treatment?