An emaciated prisoner began coughing up sputum streaked with blooD. Examination of the sputum revealed the presence of acid-fast bacilli. Which of the following would confirm a diagnosis of tuberculosis?
|A||Inclusion bodies of the nuclei of macrophages|
|B||Presence of gram-positive pleomorphic organisms|
|C||Rough, nonpigmented colonies|
|D||Rapid growth on Lowenstein-Jensen medium|
a. M. tuberculosis growth is usually slow, taking 2-8 weeks, and the colonies are rough and nonpigmented (rough, tough and buff colonies).
b. Mycobacterium tuberculosis can not be gram stained as gram stain is not able to penetrate the mycolic acid containing cell wall.