The phenomenon of 'cording' observed in virulent Mycobacterium tuberculosis colonies is attributed to which specific cell wall component?
- A Cord factor (trehalose 6,6'-dimycolate) ✓
- B Lipoarabinomannan (LAM)
- C Wax D (peptidoglycolipid)
- D Sulfolipids (acylated trehalose sulfates)
Correct answer: A. Cord factor (trehalose 6,6'-dimycolate)
Explanation
Cord factor (trehalose 6,6'-dimycolate, TDM) is responsible for the characteristic serpentine cord pattern of virulent M. tuberculosis growth, where bacilli align parallel to their long axes in clumps. Cord factor is toxic to mammalian cells, inhibits leukocyte migration, disrupts mitochondrial function, and is an important marker of virulence — avirulent strains typically lack this surface glycolipid.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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