Analisi dei determinanti del rischio di infezione tubercolare latente (ITL) nel personale sanitario di un’Azienda Ospedaliero-Universitaria in un’area a bassa incidenza di tubercolosi (TB)

Background. Health care workers (HCW) are at higher risk of latent tuberculosis infection (LTBI), but few comprehensive tuberculin skin test (TST) surveys in the different hospital units have been carried out. Methods. Community and occupational risk factors for tuberculin reactivity were determined by questionnaire and TST performed during health surveillance. Results. The overall tuberculin reactivity in 1755 HCWs was 6%. Risk factors predicting for reactivity in logistic regression analysis were occupation in microbiology [OR=4.94 (1.58-15.4)], age > 47 years [OR=2.88 (1.93-4.30)], years of work as health care worker [OR=2.57 (1.72-3.84)], history of household TB contact [OR=2.41 (1.06-5.47)], occupation in dialysis/nephrology [OR=2.00 (1.10-3.61)], gynaecology/obstetrics [OR= 2.01 (1.04-3.88)] and as a physician [OR=1.88 (1.19-2.95)], but not Bacillus Calmette-Guérin (BCG) vaccination [OR=0.39 (0.26-0.61)]. In a multiple regression model corrected for all covariates working in microbiology [OR=4.16 (1.27-13.6)], dialysis/nephrology [OR=2.52 (1.36-4.65)], gynaecology/obstetrics [OR=2.46 (1.24-4.86)] and age > 47 years [OR=1.98 (1.14-3.46)] were significant predictors for tuberculin reactivity. Conclusion. Although the overall tuberculin reactivity among the HCWs is comparable with the rates of the general population, the excess risk of LTBI can be associated with workplace risk factors in critical hospital areas. Risk assessment can direct a hospital TB surveillance program including more appropriate interventions.