A male patient returned last weekend from a vacation in Kenya where he went on safari with his wife. He presents with fever, chills, headache, nausea, and weakness. On examination he is found to have an enlarged lymph node in his groin, which is tender. A sample of blood taken from the patient shows a capsulated, bipolar-staining, gram-negative rod present in the bloodstream. The physician begins treatment of the patient with chloramphenicol immediately.
A. Which antibiotic should be started immediately?