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Multi-Drug Resistant Tuberculosis (MDR TB)

What is Multi-Drug Resistant Tuberculosis?

Tuberculosis (TB) is an infectious disease caused by a germ called Mycobacterium tuberculosis. Tuberculosis is spread through the air when a person sneezes, coughs, or breathes. Multi-Drug Resistant Tuberculosis is resistant to at least two of the main drugs used to treat TB-- isoniazid (INH), and rifampin.

TB primarily attacks the respiratory system although it can attack other organs as well. The symptoms of TB include fever, night sweats, weight loss, chest pain, and coughing.

How does TB become drug resistant?

Tuberculosis can become resistant if a patient is not treated long enough, doesn't take prescribed medications properly, or doesn't receive the right drugs.

Why is MDR TB more dangerous?

In addition to the increased difficulty in treating the disease, the patient remains infectious longer increasing the risk to the public and to healthcare workers.

MDR TB also appears in association with HIV infection and AIDS, further compromising the health and the immune system of these patients. HIV itself does not increase the chance of drug resistance. HIV does accelerate the progression of TB infection into active TB disease.

MDR TB can cause death within a few weeks in persons with HIV/AIDS.

Is MDR TB a problem in Canada?

It is estimated that one third of the world's population is infected with the TB bacillus. There were an estimated 8.4 million new cases in 1999.

In Canada, the annual incidence rate of TB has remained stable for the last decade with approximately 2,000 new cases reported each year. (Bureau of HIV/AIDS, STD and TB, Division of Tuberculosis Prevention Control, Health Canada).

Although drug-resistant TB has not yet been identified as a major problem in Canada, the potential exists due to the increase of international travel.

Can drug resistance be prevented?

The World Health Organization now strongly advocates the use of directly observed therapy (DOT). The WHO recommends that the patient be seen to swallow their medication by a trained (not necessarily medically trained) individual. Along with the proper prescription of drugs, WHO believes that DOT monitoring, which ensures that patients take the prescribed medications for the appropriate periods of time, will greatly reduce drug resistant TB.

How can we prevent the transmission of MDR TB?

The Public Health Agency of Canada, Health Canada, has developed Guidelines for Preventing the Transmission of Tuberculosis in Canadian Health Care Facilities and Other Institutional Settings.

The guidelines recommend establishing an effective infection control program aiming at:

  • Early detection of TB and prompt isolation and treatment of patients.
  • Educating health care workers about TB.
  • Screening health care workers for TB.
  • Implementing effective work practices including wearing proper respiratory protection.
  • Preventing the spread of infectious droplets into the air by using appropriate exhaust ventilation,
  • Controlling the direction of air flow to prevent air contamination adjacent to the infectious source.
  • Diluting the air through general ventilation.
  • Cleaning the air through air filtration.

Document last updated on August 31, 2006


Although every effort is made to ensure the accuracy, currency and completeness of the information, CCOHS does not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current. CCOHS is not liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the information.