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🦠microbiology review

MDR-TB

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

MDR-TB, or Multidrug-Resistant Tuberculosis, is a severe form of tuberculosis that is resistant to at least two of the most powerful first-line anti-tuberculosis drugs, isoniazid and rifampicin. This makes it much more challenging to treat and poses a significant global public health concern.

5 Must Know Facts For Your Next Test

  1. MDR-TB is a result of improper or incomplete treatment of tuberculosis, which allows the TB bacteria to develop resistance to multiple first-line antibiotics.
  2. Individuals with MDR-TB are at a higher risk of treatment failure, disease progression, and death compared to those with drug-susceptible TB.
  3. The emergence of MDR-TB is a significant global public health concern, as it requires the use of more expensive, less effective, and more toxic second-line drugs for treatment.
  4. Poor infection control measures in healthcare settings and the spread of MDR-TB strains between individuals can contribute to the further transmission and spread of this drug-resistant form of TB.
  5. Effective strategies to combat MDR-TB include early detection, appropriate treatment regimens, improved infection control, and the development of new anti-tuberculosis drugs.

Review Questions

  • Explain how the development of MDR-TB relates to the concept of Gram-positive bacteria.
    • While Mycobacterium tuberculosis, the causative agent of tuberculosis, is not a Gram-positive bacterium, the principles of drug resistance in Gram-positive bacteria are relevant to understanding the emergence of MDR-TB. Gram-positive bacteria, like many other microorganisms, can develop resistance to antibiotics through various mechanisms, such as modifying the drug target, inactivating the drug, or reducing drug accumulation within the cell. These same mechanisms can lead to the development of multidrug resistance in Mycobacterium tuberculosis, resulting in the emergence of MDR-TB strains that are resistant to multiple first-line anti-tuberculosis drugs.
  • Describe the global public health implications of the rise of MDR-TB.
    • The increasing prevalence of MDR-TB poses a significant global public health challenge. MDR-TB is more difficult and expensive to treat, often requiring the use of less effective and more toxic second-line drugs. This can lead to poorer treatment outcomes, higher rates of treatment failure, and increased transmission of drug-resistant strains within communities. The spread of MDR-TB can overwhelm healthcare systems, especially in resource-limited settings, and contribute to higher morbidity and mortality rates among affected populations. Addressing the global threat of MDR-TB requires coordinated efforts in early detection, effective treatment, improved infection control, and the development of new anti-tuberculosis drugs to combat this growing public health crisis.
  • Evaluate the role of social determinants of health in the emergence and spread of MDR-TB.
    • The emergence and spread of MDR-TB are closely linked to social determinants of health, such as poverty, limited access to healthcare, and poor living conditions. Individuals living in resource-limited settings with inadequate access to quality tuberculosis diagnosis and treatment are at a higher risk of developing MDR-TB due to incomplete or improper treatment regimens. Additionally, overcrowded living conditions and poor infection control measures in healthcare facilities can facilitate the transmission of drug-resistant TB strains within communities. Addressing the social determinants of health, including improving access to healthcare, strengthening public health infrastructure, and addressing socioeconomic inequalities, is crucial for effectively controlling the spread of MDR-TB and improving global public health outcomes.