NOSOCOMIAL OUTBREAK OF TUBERCULOSIS IN AN OUTPATIENT HIV TREATMENT-ROOM

Objective: To investigate a possible outbreak of tuberculosis in an ou tpatient HIV treatment facility in Sydney, Australia. Design: Followin g the diagnosis of pulmonary tuberculosis in an attendee, a prospectiv e screening program was instituted to investigate the potential outbre ak. Methods: Screening of 89 potentially exposed patients included che st radiographs (n = 89), and sputum examination (n = 37) over a period of 23 weeks. Results: No cases of tuberculosis were detected by the s creening program. However, three (3.4%) of this cohort developed pulmo nary tuberculosis between 8 and 10 weeks following the diagnosis of th e index case. The incidence of active tuberculosis during the follow-u p period (median, 7.4 months) was 5.3 per 100 person years and represe nts the lower limit of possible tuberculous infection, as both latent infection, and undiagnosed tuberculosis among those who died could not be excluded. Mycobacterium tuberculosis strains isolated from the ind ex case and three subsequent cases were found to be identical by DNA t yping. Conclusion: Nosocomial transmission of tuberculosis in an outpa tient treatment setting has been demonstrated. The risk of nosocomial transmission of tuberculosis is significant in institutions caring for HIV-infected patients even in countries with a low prevalence of tube rculosis infection, and highlights the importance of adherence to tube rculosis control guidlines.