Which bacterial genus is characterized by having waxy mycolic acid in its cell walls?

• A. Streptococcus
• B. Escherichia
• C. Bacillus
• D. Mycobacterium

Answer: (D)

Verified step by step guidance

1. Understand that bacterial cell wall composition is a key characteristic used to differentiate bacterial genera.
2. Recall that mycolic acids are long-chain fatty acids found in the cell walls of certain bacteria, giving them a waxy texture and making them acid-fast.
3. Identify that the genus Mycobacterium is well-known for having mycolic acid in its cell walls, which contributes to its unique staining properties and resistance to certain chemicals.
4. Compare the other options: Streptococcus (Gram-positive cocci without mycolic acid), Escherichia (Gram-negative rods without mycolic acid), and Bacillus (Gram-positive rods without mycolic acid).
5. Conclude that the presence of waxy mycolic acid in the cell wall is a defining feature of the genus Mycobacterium.