Transmission of Mycobacterium tuberculosis From Medical Waste
- Kammy R. Johnson, DVM, PhD;
- Christopher R. Braden, MD;
- K. Lisa Cairns, MD, MPH;
- Kimberly W. Field, RN, MSN;
- A. Craig Colombel, BS;
- Zhenhua Yang, PhD;
- Charles L. Woodley, PhD;
- Glenn P. Morlock, MS;
- Angela M. Weber, MS;
- A. Yvonne Boudreau, MD, MSPH;
- Thomas A. Bell, MD, MPH;
- Ida M. Onorato, MD, MPH;
- Sarah E. Valway, DMD, MPH;
- Paul A. Stehr-Green, MPH, DrPH
- Author Affiliations: Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office (Drs Johnson and Cairns), Division of Tuberculosis Elimination, National Center for HIV, STD, and TB Prevention (Drs Braden, Onorato, and Valway), and Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases (Dr Woodley and Mr Morlock), Centers for Disease Control and Prevention, Atlanta, Ga; Washington State Department of Health, Olympia and Seattle (Drs Johnson, Stehr-Green, and Cairns, Ms Field, and Mr Colombel); Central Arkansas Veterans Health Care System, Little Rock (Dr Yang); Hazard Evaluation and Technical Assistance Branch, Division of Surveillance Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, Atlanta, Ga and Denver, Colo (Ms Weber and Dr Boudreau); and Lewis County Health Officer, Chehalis, Wash (Dr Bell). Dr Johnson is now with the Health Studies Branch, Division of Environmental Hazards and Health Evaluation, National Center for Environmental Health, Centers for Disease Control and Prevention. Dr Bell is deceased.
Abstract
Context Washington State has a relatively low incidence rate of tuberculosis (TB) infection. However, from May to September 1997, 3 cases of pulmonary TB were reported among medical waste treatment workers at 1 facility in Washington. There is no previous documentation of Mycobacterium tuberculosis transmission as a result of processing medical waste.
Objective To identify the source(s) of these 3 TB infections.
Design, Setting, and Participants Interviews of the 3 infected patient-workers and their contacts, review of patient-worker medical records and the state TB registry, and collection of all multidrug-resistant TB (MDR-TB) isolates identified after January 1, 1995, from the facility's catchment area; DNA fingerprinting of all isolates; polymerase chain reaction and automated DNA sequencing to determine genetic mutations associated with drug resistance; and occupational safety and environmental evaluations of the facility.
Main Outcome Measures Previous exposures of patient-workers to TB; verification of patient-worker tuberculin skin test histories; identification of other cases of TB in the community and at the facility; drug susceptibility of patient-worker isolates; and potential for worker exposure to live M tuberculosis cultures.
Results All 3 patient-workers were younger than 55 years, were born in the United States, and reported no known exposures to TB. We did not identify other TB cases. The 3 patient-workers' isolates had different DNA fingerprints. One of 10 MDR-TB catchment-area isolates matched an MDR-TB patient-worker isolate by DNA fingerprint pattern. DNA sequencing demonstrated the same rare mutation in these isolates. There was no evidence of personal contact between these 2 individuals. The laboratory that initially processed the matching isolate sent contaminated waste to the treatment facility. The facility accepted contaminated medical waste where it was shredded, blown, compacted, and finally deactivated. Equipment failures, insufficient employee training, and respiratory protective equipment inadequacies were identified at the facility.
Conclusion Processing contaminated medical waste resulted in transmission of M tuberculosis to at least 1 medical waste treatment facility worker.
- KEYWORDS:
- disease transmission
- medical waste
- mycobacterium tuberculosis
- occupational exposure
- tuberculosis
