In contrast, in just 3 hours, all five previously uninfected persons became infected, with two becoming culture positive albeit without symptoms or radiographic abnormality. Autopsy room workers have long been known to be at considerable risk for acquiring tuberculosis. Little is known about why autopsy room workers are at such increased risk for tuberculosis. One possibility is that autopsy workers can be exposed to patients not suspected of having tuberculosis, particularly when the clinical picture is atypical, as in hematogenous dissemination, peritonitis, and meningitis. Another factor is that certain procedures are done only in autopsy rooms.
Several points deserve emphasis.
First, in this outbreak of tuberculosis, the autopsy personnel inhaled air containing the highest concentration of infectious particles yet described. Among nurses working on tuberculosis wards before the chemotherapy era, tuberculin skin test results converted in about 1 year. Second, none of the previously known reactors developed tuberculosis, even though they had not received preventive therapy. Indeed, one pathology technician, a known reactor, was present throughout the 3-hour necropsy and must have inhaled a very large number of organisms, perhaps 18 infectious units. The fact that none of the five known reactors developed tuberculosis suggests that in a healthy person, a previous tuberculous infection is associated with substantial resistance to reinfection.