Mycobacterium leprae is a slow grower
Group of answer choices
True
False
The correct answer and explanation is:
The correct answer is True.
Mycobacterium leprae is indeed a slow-growing bacterium. It is the causative agent of leprosy, also known as Hansen’s disease. Unlike many other bacteria, which can grow rapidly in laboratory conditions, M. leprae has a very slow growth rate. This characteristic is due to its unique biology, including its need for specific environmental conditions and the complex nature of its interactions with the host.
Mycobacterium leprae is an intracellular pathogen, which means it primarily survives and multiplies within the cells of its host, particularly within macrophages and Schwann cells. This makes it difficult to culture in standard laboratory settings. In fact, it has not been successfully cultured on standard laboratory media to date. Instead, researchers rely on animal models, such as the armadillo, to propagate the bacteria for study.
The slow growth rate of M. leprae is related to its unique cell wall structure, which is rich in mycolic acids. These long-chain fatty acids make the cell wall very thick and waxy, providing resistance to environmental stresses, including desiccation and antibiotic penetration. This also contributes to the slow replication rate of the bacteria.
Additionally, the ability of M. leprae to grow in peripheral nerves and skin contributes to the chronic nature of leprosy. Leprosy is characterized by long incubation periods, often taking years before symptoms, such as skin lesions and nerve damage, manifest. This slow progression contributes to the difficulty in diagnosing and treating the disease, as symptoms may not appear until long after initial infection.
Therefore, the slow-growing nature of Mycobacterium leprae is a defining feature of the pathogen and contributes to both its biological behavior and its clinical challenges.