A 75-year-old woman has developed increasing difficulty breathing for the past 2 weeks. On physical examination, she has diffuse rales in all lung fields. Scleral icterus is noted. A complete blood count shows hemoglobin 7.4 g/dl, hematocrit 22.4%, MCV 92 fL, platelet count 200,000/microliter and total WBC count 6800/microliter with a differential count of 60% neutrophils, 5% bands, 24% lymphocytes, 9% monocytes and 2% eosinophils along with 10 nucleated RBCs/100 WBCs.

Which of the following is the most likely diagnosis?