OUTBREAK OF TUBERCULOSIS AMONG REGULAR PATRONS OF A NEIGHBORHOOD BAR

Background. Outbreaks of tuberculosis have been reported in prisons, n ursing homes, urban homeless shelters, and other crowded settings. We report a nonresidential outbreak of tuberculosis that originated in a neighborhood bar. Methods. A homeless patient with highly infectious p ulmonary tuberculosis was a regular patron of a neighborhood bar durin g a long symptomatic interval before diagnosis. We investigated 97 oth er regular customers and employees of the bar through interviews, tube rculin skin testing, and chest roentgenography, We performed DNA finge rprinting on isolates from the index patient and 11 other patients. Re sults. The index patient apparently infected 41 of 97 contacts (42 per cent), resulting in 14 cases of active tuberculosis and 27 cases of in fection but no disease (indicated by positive tuberculin skin tests). Four other cases of active tuberculosis occurred among regular custome rs of the bar who were missed by the contact investigation. There were also two secondary cases. Radiographic findings in active cases inclu ded upper-lobe disease in seven cases (three cavitary) and negative ch est films at the time of diagnosis in four cases. All 12 culture isola tes we tested had the same chromosomal-DNA restriction pattern. Conclu sions. The spread of tuberculosis in a neighborhood bar can be a major public health problem. The high rate of infection and disease among t he contacts was unexpected and was not due to coinfection with the hum an immunodeficiency virus. Possible explanations include heavy alcohol use among the contacts, high infectivity of the index case, or both. Sputum cultures must be performed in tuberculin-positive contacts who have symptoms, even if the chest films are normal.