Case 3

1. Presented by Eugene Brooks, MD and reviewed by Sean Zhang, MD

An elderly patient presented with a chief complaint of shortness of breath and fatigue of a month's duration. The patient also reported occasional chills, night sweats and one episode of syncope. Their past medical history was significant for dilated cardiomyopathy for which the patient had an implanted cardiac pacemaker and defibrillator. Physical exam was notable for hypotension. Remarkable values from initial blood work are seen below.

ValueNormal Ranges
Platelet Count15 K/cu mm(150-350 K/cu mm)
Prothrombin Time (PT)57.5 sec(9.6 - 11.8 sec)
Activated Prothrombin Time (PTT)38.6 sec(22.9 - 30.6 sec)
D-Dimer>30 mg/L(0.17 - 0.88 mg/L)
Galactomannan (serum)7.89(positive if >0.5)
Beta D-Glucan (1-3) (blood)>500 pg/mL(negative if <60)

An echocardiogram revealed a large mass involving the tricuspid valve with encapsulation of nearby defibrillator leads. The mass and leads were surgically removed and tissue submitted for bacterial/fungal cultures (results are seen below). Up to this point, all peripheral blood cultures were negative.

Fig 1: Calcofluor white stain of submitted tissue.

Fig 2: Slant Culture

Fig 3: Microscopic examination.

Question: The patient's presentation and laboratory findings are best explained by infection with: