Reduction in tuberculin skin-test conversions among medical house staff associated with improved tuberculosis infection control practices.

OBJECTIVE: To assess the efficacy of an infection control program as measured by tuberculin skin-test (TST) conversion rates in medical house staff. DESIGN: Observational study. SETTING: University-based hospital in New York City serving a large indigent population. PARTICIPANTS: Medical house staff. INTERVENTIONS: TST conversions were measured every 6 months in medical house staff from June 1992 to June 1994. Compliance with the isolation policy was measured by identifying room locations 24 hours after admission of patients who had Mycobacterium tuberculosis recovered from respiratory specimens. RESULTS: The TST conversion rate decreased from 5.8 to 0, 2.3, and 0 per 100 person years of exposure in successive 6-month periods. The estimated annual TST conversion rate among interns fell from 7 per 100 person years in June 1992 to 0 per 100 person years in June 1993 and 0 per 100 person years in June 1994 (P < .029). The proportion of patients with pulmonary tuberculosis who were isolated in negative-pressure rooms increased from 38% to 75% over the study period (P < .01). CONCLUSION: Development of a multifaceted infection control program can decrease the risk of nosocomial tuberculosis infection in medical house staff.