A 21-year-old patient with leukemia is admitted to the hospital with a temperature of 38.9°C and a nonproductive cough 8 days after induction chemotherapy completion. Laboratory tests show a WBC count of 1,000 cells/ul (10% segmented neutrophils, 0% bands, and 90% lymphocytes) and a platelet count of 60,000 cells/uL. Chest X-ray reveals a small left lower lobe infiltrate. Blood, urine, and sputum cultures are obtained. What should be the recommendation for initial management?