Which statement about Mycobacterium leprae is true?

Which statement about Mycobacterium leprae is true?

• A. It can be grown on artificial media
• B. It is transmitted easily between people
• C. It grows rapidly in culture
• D. It cannot be grown on artificial media and requires animals for cultivation

Answer: (D)

The main idea here is how Mycobacterium leprae grows. This organism cannot be cultured on standard artificial laboratory media; it requires living tissue to multiply. Its growth is extremely slow, so it has historically been grown only in animal hosts—such as the mouse footpad model or armadillos—where host cells provide the factors it needs. Because of this dependence on a living system and its slow replication, it isn’t something you grow in routine culture media. That’s why the statement describing it as not growing on artificial media and needing animals for cultivation is the true one. Leprosy itself isn’t highly contagious and doesn’t spread as readily as tuberculosis, and the organism does not rapidly grow in culture, which helps explain why in vitro growth isn’t feasible.

The main idea here is how Mycobacterium leprae grows. This organism cannot be cultured on standard artificial laboratory media; it requires living tissue to multiply. Its growth is extremely slow, so it has historically been grown only in animal hosts—such as the mouse footpad model or armadillos—where host cells provide the factors it needs. Because of this dependence on a living system and its slow replication, it isn’t something you grow in routine culture media. That’s why the statement describing it as not growing on artificial media and needing animals for cultivation is the true one. Leprosy itself isn’t highly contagious and doesn’t spread as readily as tuberculosis, and the organism does not rapidly grow in culture, which helps explain why in vitro growth isn’t feasible.