Effectiveness of a nosocomial tuberculosis control program at an urban teaching hospital

Study objective: To assess the effectiveness of a nosocomial tuberculosis (TB) program at an urban teaching hospital. Design: Retrospective review. Setting: An urban teaching hospital, the University of California, San Diego Medical Center (UCSD), which cares for 25 to 30 culture-proven pulmonary TB cases (>80% of which are smear-positive) per year. Study population: Health-care workers. Measurements: (1) Purified protein derivative (PPD) conversion rates. (2) Cases of active TB among health-care workers. (3) Compliance rates with isoniazid (INH) preventive therapy. Results: The UCSD program was evaluated for the pears 1993 to 1995. The PPD conversion rate among established employees was 0.6%. Of 556 employees who had an exposure, 494 (88.8%) were compliant with follow-up. Three hundred thirty-seven were skin-tested (the other 157 already had a known PPD > 10 mm). Only 2 of 337 (0.6%) converted. One case of active TB, unrelated to any documented hospital exposure, was discovered in 3 years among approximately 5,000 employees per year (follow-up for convertors, 18 to 54 months). Only 48.4% of eligible employees completed at least 6 months of INH preventive therapy. Conclusions: UCSD's TB control measures appear to be effective in the prevention of nosocomial transmission of TB, Despite poor compliance with INH preventive therapy, cases of active TB among health-care workers were rare.