A nosocomial outbreak of multidrug-resistant tuberculosis

Ann Intern Med. 1997 Jul 1;127(1):32-6. doi: 10.7326/0003-4819-127-1-199707010-00006.


Background: An outbreak of seven cases (in six patients and one health care worker, all of whom had AIDS) of multidrug-resistant tuberculosis occurred in a hospital in Chicago. The hospital had a respirator-fit testing program but no acid-fast bacilli isolation rooms.

Objective: To identify risk factors for transmission of Mycobacterium tuberculosis.

Design: Retrospective cohort study.

Setting: Private hospital.

Participants: Patients and health care workers exposed to M. tuberculosis.

Measurements: Analysis of M. tuberculosis isolates, tuberculin skin testing, assessment of exposure, and assessment of participant characteristics.

Results: All seven M. tuberculosis isolates had matching DNA fingerprints. Of patients exposed to M. tuberculosis, those who developed tuberculosis had lower CD4+ T-lymphocyte counts (P = 0.02) and were more likely to be ambulatory (P = 0.03) than those who did not. Of 74 exposed health care workers, the 11 (15%) who had conversion on tuberculin skin testing were no more likely than those who did not have conversion to report that they always wore a respirator with a high-efficiency particulate air filter.

Conclusions: Transmission of M. tuberculosis occurred in a hospital that did not have recommended isolation rooms. A respirator-fit testing program did not protect health care workers in this setting.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • AIDS-Related Opportunistic Infections / epidemiology*
  • AIDS-Related Opportunistic Infections / transmission
  • Chicago / epidemiology
  • Cross Infection / epidemiology*
  • Cross Infection / transmission
  • DNA Fingerprinting
  • Disease Outbreaks*
  • Humans
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / isolation & purification
  • Retrospective Studies
  • Risk Factors
  • Tuberculosis, Multidrug-Resistant / epidemiology*
  • Tuberculosis, Multidrug-Resistant / transmission