Mycobacterium tuberculosis

Definition

Mycobacterium tuberculosis is the bacterial pathogen responsible for causing tuberculosis (TB), a serious infectious disease that primarily affects the lungs. It is a slow-growing, rod-shaped, acid-fast bacterium that can lie dormant in the body for years before reactivating and causing active disease.

5 Must Know Facts For Your Next Test

1. Mycobacterium tuberculosis is transmitted through the inhalation of aerosolized droplets containing the bacteria, typically from an infected individual coughing or sneezing.
2. The bacterium primarily targets the lungs, but it can also spread to other organs, such as the lymph nodes, kidneys, and brain, causing extrapulmonary tuberculosis.
3. Mycobacterium tuberculosis has a unique cell wall structure that makes it resistant to many antibiotics and contributes to its ability to evade the host's immune system.
4. Individuals with weakened immune systems, such as those with HIV/AIDS or those undergoing immunosuppressive therapy, are at a higher risk of developing active tuberculosis.
5. The emergence of drug-resistant strains of Mycobacterium tuberculosis, such as multidrug-resistant (MDR-TB) and extensively drug-resistant (XDR-TB), poses a significant challenge in the treatment and control of tuberculosis.

Review Questions

• Describe the key characteristics of Mycobacterium tuberculosis that contribute to its ability to cause tuberculosis.
  • Mycobacterium tuberculosis is a slow-growing, rod-shaped, acid-fast bacterium with a unique cell wall structure that makes it resistant to many antibiotics. This cell wall composition also allows the bacterium to evade the host's immune system, enabling it to persist in the body and cause active disease even after the initial infection. Additionally, the ability of Mycobacterium tuberculosis to form granulomas in the lungs and other tissues is a hallmark of the tuberculosis disease process, leading to the development of characteristic symptoms such as cough, fever, and weight loss.
• Explain the difference between latent TB infection (LTBI) and active tuberculosis disease, and discuss the factors that can lead to the reactivation of latent infection.
  • Latent TB infection (LTBI) occurs when a person is infected with Mycobacterium tuberculosis, but the immune system has successfully contained the infection, and the person does not have active symptoms of tuberculosis. In contrast, active tuberculosis disease is characterized by the presence of the bacteria actively multiplying and causing clinical manifestations of the disease. Factors that can lead to the reactivation of latent infection and the development of active tuberculosis include weakened immune systems, such as in individuals with HIV/AIDS or those undergoing immunosuppressive therapy. Additionally, the emergence of drug-resistant strains of Mycobacterium tuberculosis, such as multidrug-resistant (MDR-TB) and extensively drug-resistant (XDR-TB), can contribute to the reactivation of latent infection and the progression to active disease, posing significant challenges in the treatment and control of tuberculosis.
• Analyze the public health implications of the transmission and spread of Mycobacterium tuberculosis, and discuss strategies for the prevention and control of tuberculosis at the population level.
  • The transmission of Mycobacterium tuberculosis through the inhalation of aerosolized droplets from infected individuals has significant public health implications. The ability of the bacterium to spread through the air and the potential for latent infection to reactivate pose challenges in the control and eradication of tuberculosis. Strategies for the prevention and control of tuberculosis at the population level include early diagnosis and treatment of active cases, contact tracing and screening of individuals who have been exposed, the implementation of directly observed therapy (DOT) to ensure treatment adherence, and the development of effective vaccines to prevent the initial infection. Additionally, addressing social determinants of health, such as poverty, malnutrition, and access to healthcare, can play a crucial role in reducing the burden of tuberculosis in communities.

Related terms

Tuberculosis (TB):

A contagious infectious disease caused by the bacterium Mycobacterium tuberculosis, characterized by the formation of granulomas in the lungs and other tissues, leading to symptoms such as cough, fever, and weight loss.

Latent TB Infection (LTBI): A condition in which a person is infected with Mycobacterium tuberculosis, but the immune system has contained the infection, and the person does not have active symptoms of tuberculosis.

Acid-fast Bacilli (AFB): A group of bacteria, including Mycobacterium tuberculosis, that are resistant to decolorization by acid-alcohol solutions during the Ziehl-Neelsen staining procedure, allowing them to be easily identified under a microscope.