Background: The risk for nosocomial transmission of tuberculosis exists in health care institutions. Objective: To evaluate indicators of transmission risk among patients with pulmonary tuberculosis treated at a university hospital. Method: A retrospective study covering the January 1997 to September of 1999 period and evaluating patients admitted to the Hospital de Clínicas of the Universidade Estadual de Campinas with pulmonary tuberculosis. Three intervals were determined: from admission to collection of sputum for acid-fast bacilli microscopy; from admission to implementation of airborne infection control measures; from sputum collection to the initiation of treatment. Results: The final sample included 63 cases. Concomitant human immunodeficiency virus-positivity was found in 31.7%. Forty patients (63.5%) were admitted through the emergency room. In 42 (66.7%) patients, TB was suspected at admission. The interval between admission and sputum collection exceeded 12 hours in 27.5% of cases admitted through the emergency room and in 30.4% of those admitted directly to wards (p = 0.803). Delayed respiratory isolation occurred in 31 cases (49.2%). The delay in isolation was correlated to no diagnosis of tuberculosis at admission (p < 0.000) and lower bacillary load in the sputum (p = 0.032). Co-infection with human immunodeficiency virus (p = 0.530), hospitalization ward (p = 0.284) and underlying diseases (p = 0.541) were not correlated with delayed isolation. The interval between sputum collection and initiation of treatment was greater than 24 hours in 15.9% of the cases. Conclusion: Delayed isolation was observed in many cases. Policies of continuing education are called for, especially in high-risk areas.

Keywords: Tuberculosis. Infection Control. Brazil. Delay. Diagnosis.