Tuberculosis is caused by which type of pathogen?

• A. Mycobacterium
• B. Staphylococcus
• C. Virus
• D. Fungi

Answer: (A)

TB is caused by a bacterium, specifically a Mycobacterium genus member (most often Mycobacterium tuberculosis). This organism is a slow-growing, aerobic, acid-fast bacillus with a waxy, lipid-rich cell wall that makes it resistant to standard staining and decolorization, which is why special staining like Ziehl-Neelsen is used. TB is primarily a pulmonary disease but can affect other parts of the body, and it spreads through airborne droplets when an infected person coughs or sneezes. This distinguishes it from viruses (which are not cellular and require host cells), fungi (which are a different type of microorganism with distinct diseases), or Staphylococcus (a different bacterium that causes other infections).