Review Question - QID 110002

A 7-year-old boy presents to the emergency department with a cough and fever. He has had a cough for the past day. The child was born full term to a G1P1 mother. He has had repeat pulmonary infections since birth, poor weight gain, and a positive sweat chloride test. His temperature is 103°F (39.4°C), blood pressure is 101/64 mmHg, pulse is 112/min, and respirations are 19/min. A chest radiograph is performed and the results are seen in Figure A. The child is admitted and treated appropriately. This patient presents for a similar chief complaint 20 years later at the age of 27. Which of the following represents the optimal antibiotic choice for this patient when he was 7-years-old (1) and when he was 27-years-old (2)?