Transmission of Mycobacterium tuberculosis from medical waste.
BACKGROUND
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.


METHODS
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.


METHODS
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.


CONCLUSIONS
Processing contaminated medical waste resulted in transmission of M tuberculosis to at least 1 medical waste treatment facility worker. JAMA. 2000;284:1683-1688.
Johnson
K R
KR
Centers for Disease Control and Prevention, 1600 Clifton Rd NE, MS E-23, Atlanta, GA 30333, USA. kdj8@cdc.gov
Braden
C R
CR
Cairns
K L
KL
Field
K W
KW
Colombel
A C
AC
Yang
Z
Z
Woodley
C L
CL
Morlock
G P
GP
Weber
A M
AM
Boudreau
A Y
AY
Bell
T A
TA
Onorato
I M
IM
Valway
S E
SE
Stehr-Green
P A
PA
D000328:Adult; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D008506:Medical Waste; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification; D009784:Occupational Diseases / Q000453:epidemiology; D016273:Occupational Exposure; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000209:etiology*; D014861:Washington / Q000453:epidemiology
D004269:DNA, Bacterial; D008506:Medical Waste