Review Question - QID 109324

A 70-year-old woman is admitted to the hospital from a nursing home with a fever, shortness of breath, and a productive cough. She reports that when she coughs, she brings up foul-smelling phlegm. Upon arrival, a physical examination is significant for left basilar crackles and dullness to percussion. A chest radiograph shows left lower lobe pneumonia. She is given vancomycin and high-dose levofloxacin. Over her hospital stay, the patient remains febrile and her dyspnea worsens. A follow-up chest radiograph is obtained and the results are shown in Figure A. A chest tube is inserted and a fluid is sent for analysis. Labs are also drawn. The results are shown below:

Pleural fluid:
Gross appearance: Cloudy, yellow
pH: 6.92
Leukocyte count and differential:
Leukocyte count: 60,000/mm^3
Segmented neutrophils: 95%
Protein: 4.3 g/dL
Lactate dehydrogenase: 265 U/L
Glucose: 24 mg/dL
ADA level: 27 units/L

Serum:
Protein: 5.4 g/dL
Lactate dehydrogenase: 280 U/L

A culture and a gram stain of the pleural fluid are pending. Which of the following is the most appropriate next step in the management of this patient’s condition?