A previously healthy 27-year-old male presents to the emergency department in mid-July with a 5-day history of fever, chills, severe frontal headache, diffuse muscle aches, and nausea. He returned from a camping trip in Tennessee approximately one week ago. Vital signs upon presentation show temperature 39.3°C (102.7°F), heart rate 112 bpm, blood pressure 98/64 mmHg, and respiratory rate 20/min. On physical examination, the patient appears acutely ill and has a diffuse maculopapular rash involving his palms and soles. There is no neck rigidity, and cardiopulmonary examination is normal. Laboratory studies reveal:
| Laboratory Test | Result | Normal Range |
|---|---|---|
| WBC | 3,400/mm³ | (4,500–11,000/mm³) |
| Platelets | 62,000/mm³ | (150,000–400,000/mm³) |
| Hemoglobin | 13.8 g/dL | (13.5–17.5 g/dL) |
| Sodium | 130 mEq/L | (135–145 mEq/L) |
| AST | 112 U/L | (10–40 U/L) |
| ALT | 95 U/L | (10–40 U/L) |
| Creatinine | 1.2 mg/dL | (0.6–1.2 mg/dL) |
Given the clinical findings and lab abnormalities, immediate empiric antibiotic therapy is initiated pending confirmatory testing.
Which of the following antibiotics is the most appropriate initial therapy?
A. Ceftriaxone
B. Ciprofloxacin
C. Vancomycin
D. Doxycycline
E. Chloramphenicol
