A 60-year-old man with a chronic cough, bloody sputum, and marked weight loss is diagnosed as having tuberculosis. A "serpentine-like" colonial morphology is noted on Lowenstein-Jensen agar. This latter finding is caused by which of the following factors: (A) A large "slimy" capsule, (B) Wax D, (C) Coagulase, (D) Cord factor
Answer is D. Virulence of the organism is correlated with cord factor (trehalose dimycolate).