A 31-year-old, HIV-infected man from New York presents to the ER with anorexia, malaise, night sweats, fever, and weight loss of 6.8kg (151b) over the past one month. He also has a cough productive of yellow sputum. He was diagnosed with HIV two years ago. When last checked two months ago, his CD4 count was 220/microL. He is not taking any medications. His temperature is 39.2C (102.2F), pulse is 96/min, and blood pressure is 120/80 mm Hg. Physical examination reveals rales in his right upper chest. Laboratory studies show:
Hematocrit 30%
WBC count 3,400/microL
Neutrophils 86%
Bands 2%
Lymphocytes 4%
Monocytes 8%
PPD test shows 3 mm induration. Chest x-ray reveals a right upper lobe cavitation. Sputum examination shows partially acid-fast, filamentous, branching rods. Based on these findings, which of the following organism is the most likely cause of this patient’s pulmonary disease?
A. Pneumocystis jiroveci
B. Mycobacterium tuberculosis
C. Coccidioides species
D. Nocardia species
E. Streptococcus pneumonia