Assessing occupational exposure as risk for tuberculous infection at a teaching hospital in São Paulo, Brazil

OBJECTIVE: To determine the risk for TB infection among nurses exposed to TB patients and non-exposed employees, and to evaluate associated aspects to initiate TB prevention in a teaching hospital in Brazil.

DESIGN: A cross-sectional tuberculin skin test (TST) survey and assessment questionnaire of 169 nurses exposed to patients (exposed group [EG]) and 164 administrative employees (comparative group [CG]).

RESULTS: The prevalence of positive TST was 59.7% in the EG and 53.7% in the CG (P = 0.26). Univariate analysis revealed, in the CG, association of TST positivity with BCG scar (P = 0.002), and, in the EG, with male sex (P = 0.02) and working at that hospital for >2 years (P < 0.001). On multivariate analysis, male sex (P = 0.0444), working at the institution for >2 years (P < 0.0001) and BCG scar (P = 0.0004) were associated with positive TST, while occupational exposure was not.

CONCLUSIONS: The results suggest that all health care workers should be evaluated in an institutional TB prevention programme because community exposure to TB and BCG vaccination may have influenced TST positivity in the studied population.