Nosocomial Tuberculosis Exposure in an Outpatient Setting Evaluation of Patients Exposed to Healthcare Providers With Tuberculosis

Abstract

Objective:To evaluate the risk of tuberculosis (TB) transmission to patients potentially exposed to two healthcare providers who worked in outpatient settings for several weeks prior to being diagnosed with acid-fast bacilli smear-positive pulmonary TB.Design:Potentially exposed patients were notified by letter and television reports of the recommended evaluation for TB infection or disease and availability of free screening at the hospital. Prevalence of infection in the screened patients and the incidence rate of TB over the subsequent 2 years were compared to those of a control group of unexposed outpatients.Setting:An urban inner-city hospital.Patients:1,905 patients with potential exposure to the ill healthcare workers; 487 (25%) presented for evaluation. Controls consisted of 951 unexposed patients.Results:361 potentially exposed patients had their tuberculin test read; 97 (27%) had a purified protein derivative ≥10 mm. In the comparison group, 148 (25%) of 600 with test readings had a ≥10-mm reaction (risk ratio, 1.18; 95% confidence interval, 0.86-1.60). In multivariate analysis, male gender, non-white race, and older age were significantly associated with a positive tuberculin test; exposure was not. No TB cases were identified during screening. Two years after the exposure, 7 TB cases had been reported to the state registry among 1,905 potentially exposed patients (184 cases/100,000 person-years) versus 4 cases in the comparison group of 951 (210 cases/100,000 person-years).Conclusions:Evaluation of patients exposed to health-care workers with TB disease in ambulatory settings of an inner-city hospital revealed no evidence of transmission ofMycobacterium tuberculosisdue to the exposure.