Historical risks of tuberculin skin test conversion among non-physician staff at a large urban hospital.

BACKGROUND

Nosocomial transmission of Mycobacterium tuberculosis among workers at a 1000-bed inner-city hospital led to an extensive evaluation of this risk among workers with potential exposure to TB patients or laboratory specimens.

METHODS

Retrospective cohort study to determine the incidence and risk of tuberculin skin test (TST) conversions among workers employed 1/1/90 to 9/30/92.

RESULTS

Personal, community, and occupational risk factors were evaluated in 2,362 workers with potential M. tuberculosis exposure and 886 workers with no known exposure. The 33-month cumulative rate of TST conversion was 5.8% for potentially exposed workers and 2.0% for controls (RR 3.6; 95% CI; 2.2-5.8). Among workers with potential M. tuberculosis exposure, statistically significantly elevated risks were found for nurses, laboratory technicians, pharmacy workers, phlebotomists, housekeepers, clerks, emergency room workers, and emergency responders.

CONCLUSIONS

Workers with patient contact and those employed in certain occupational groups were at increased risk for occupational M. tuberculosis infection.