Mycobacterium leprae

Definition

Mycobacterium leprae is a slow-growing, rod-shaped bacterium that is the causative agent of leprosy, a chronic infectious disease primarily affecting the skin, peripheral nerves, upper respiratory tract, and eyes. It is classified as a bacterium that can cause diseases of the nervous system.

5 Must Know Facts For Your Next Test

1. Mycobacterium leprae is an obligate intracellular pathogen, meaning it can only replicate within the cells of the human host.
2. The bacteria have a predilection for cooler areas of the body, such as the skin, peripheral nerves, and nasal mucosa, which is why they primarily affect these regions.
3. Leprosy is transmitted through direct contact with nasal secretions or skin sores of individuals with untreated, multibacillary leprosy, as well as through the inhalation of respiratory droplets.
4. The incubation period for leprosy can range from 2 to 20 years, making it a slowly progressing disease.
5. Mycobacterium leprae is a slow-growing bacterium, with a doubling time of approximately 12-14 days, contributing to the chronic nature of the disease.

Review Questions

• Explain the unique characteristics of Mycobacterium leprae that enable it to cause disease in the nervous system.
  • Mycobacterium leprae is an obligate intracellular pathogen that has a predilection for cooler areas of the body, such as the skin and peripheral nerves. This allows the bacteria to thrive and replicate within these tissues, leading to the formation of granulomas and the subsequent damage to the nervous system. Additionally, the slow-growing nature of the bacteria, with a doubling time of 12-14 days, contributes to the chronic and progressive nature of the disease, as it takes time for the bacteria to cause significant nerve damage and disability.
• Describe the transmission and incubation period of leprosy caused by Mycobacterium leprae.
  • Leprosy is primarily transmitted through direct contact with nasal secretions or skin sores of individuals with untreated, multibacillary leprosy, as well as through the inhalation of respiratory droplets. The incubation period for leprosy can range from 2 to 20 years, making it a slowly progressing disease. This extended incubation period is due to the slow-growing nature of Mycobacterium leprae, which allows the bacteria to gradually establish infection and cause the characteristic skin and nerve lesions associated with leprosy.
• Analyze the role of the immune system in the pathogenesis of leprosy caused by Mycobacterium leprae.
  • The immune system plays a crucial role in the pathogenesis of leprosy caused by Mycobacterium leprae. The bacteria's ability to form granulomas, which are localized collections of immune cells, particularly macrophages, is a hallmark of the host's immune response to the infection. The formation of these granulomas is an attempt by the immune system to contain and eliminate the slow-growing bacteria. However, the persistent nature of Mycobacterium leprae and its ability to evade the immune system's defenses can lead to the gradual destruction of the peripheral nerves and other affected tissues, resulting in the characteristic symptoms and disabilities associated with leprosy.

Related terms

Leprosy: A chronic infectious disease caused by Mycobacterium leprae, characterized by the formation of granulomas in the skin and peripheral nerves, leading to skin lesions, nerve damage, and disability.

Granuloma: A localized collection of immune cells, typically macrophages, that form in response to an infection or foreign material, as seen in the skin and nerves of individuals with leprosy.

Acid-Fast Bacilli: A group of bacteria, including Mycobacterium leprae, that are resistant to decolorization by acid-alcohol solutions during the Gram staining process, allowing them to be easily identified under a microscope.