No abstract

Six employees of the emergency department at Parkland Memorial Hospital developed active tuberculosis in 1983-1984. Five of the cases occurred four to 12 months after exposure to the index case, a patient with severe cavitary tuberculosis seen in the emergency department in April 1983. One resident physician developed cavitary disease after exposure to this patient. An additional employee case may have resulted from transmission from one of the initial employee cases. One immunocompromised patient may have acquired tuberculosis as a result of exposure to the index case. In addition, the tuberculin skin tests of at least 47 employees exposed to the index case converted from negative to positive. Of 112 previously tuberculin-negative emergency department employees who were tested in October 1983, 16 developed positive skin tests, including the 5 employees with active disease. Fifteen of these new positives had worked on April 7, 1983, while the index case was in the emergency department (X2 = 20.6, P less than 0.001). Factors related to the genesis of the epidemic included the disease characteristics in the index case and the recirculation of air in the emergency department. This investigation indicates that city-county hospital emergency department employees should be screened at least twice a year for evidence of tuberculosis and that the employee health services of such hospitals should regard the surveillance of tuberculosis infection among personnel at a high-priority level.

Profile analysis of mycolic acid ester patterns of Mycobacterium tuberculosis, Mycobacterium bovis, and Mycobacterium bovis bacillus Calmette-Guerin (BCG) using high-performance liquid chromatography indicated that separation of BCG from M. tuberculosis and M. bovis by elution and relative retention times is possible. Mycolic acid patterns of BCG eluted from the column 0.5 min before M. tuberculosis or M. bovis, resulting in relative retention times for two peaks not seen in the pattern of M. tuberculosis or M. bovis. Identification was confirmed by phage typing, which has been the standard procedure for confirmation of BCG strains. These results showed that high-performance liquid chromatographic analysis of mycolic acid esters can be used in the mycobacterial reference laboratory for separation of BCG from M. tuberculosis and M. bovis. The Mycobacterium tuberculosis complex contains subspecies such as Mycobacterium bovis bacillus Calmette-Guierin (BCG) that are difficult to differentiate by conven-* Corresponding author.

The kinetics of inactivation of mycobacteria by ultraviolet light were investigated. Mycobacterium tuberculosis and M. marinum were shown to be capable of photo-reactivation.

Colony changes from rough to smooth were observed in a rough strain of mycobacterium ATCC 607 after exposure to phages D29 and B4. The colonies surviving after exposure to these two phages were both smooth and lysogenic. Increased nitrate reductase and Tween 80 hydrolytic activities accompanied lysogenization. Loss of lysogeny was accompanied by conversion to the rough colony type and a decrease in nitrate reductase and Tween 80 hydrolytic activities. The rapid loss and gain of these multiple characteristics suggested that the genetic control lies in a plasmid of mycobacteria.