A NOSOCOMIAL OUTBREAK OF MYCOBACTERIUM-TUBERCULOSIS

Background. The national incidence of tuberculosis (TB) is increasing, and hospitals are a site of transmission. We investigated a nosocomia l outbreak of TB at a 160-bed community hospital in South Carolina tha t highlights the central role that primary care physicians must play t o control this epidemic. Methods. We reviewed medical records to ident ify potential source cases. We retrospectively evaluated exposures to suspected source patients and the subsequent tuberculin reactivity of the 38 hospital employees who had a previous negative tuberculin skin test and were assigned to the ward where the outbreak began. We also e valuated the out-of-hospital contacts of TB cases. Results. A review o f medical records identified one patient who had died of prostate canc er and chronic cavitary pneumonia but was never in isolation nor evalu ated for TB. Ward employees who worked while this patient was hospital ized had an increased risk for skin-test conversion (43% [12 of 28] vs 0% [0 of 9]; relative risk undefined; P=.02). Among employees who wor ked with this patient, skin-test converters worked more shifts with (m edian, 10.5 vs 7), dispensed more medication to (median 7 doses vs 1), and wrote more notes on (median 18 vs 5) the index patient than did n onconverters. Five of 12 of the patient's close out-of-hospital contac ts had newly recognized positive tuberculin skin tests. Among 20 casua l contacts, there were no new skin-test conversions. Conclusions. A hi gh index of suspicion, prompt isolation and diagnostic testing of pote ntially infectious hospitalized patients, and a thorough investigation of contacts of patients with TB are needed to prevent TB transmission .