Risk factors of latent tuberculosis infection and immune function in health care workers in Suzhou, China.

Background The Chinese government has pay attention about tuberculosis infection among medical staff in infectious disease hospitals, but the effects have not yet been reported. This study will explore latent infection and immune function in the medical staff and systematically analyze the associated influencing factors. Methods Ninety-four medical staffs were enrolled and 20 medical staffs were defined as low risk group and others were high risk group. We used IFN-γ release assay and flow cytometry to analyze the latent TB infection status and immune function. Logistic regression analyses were performed to identify the independent risk factors of latent TB infection. Results This study explored and compared the infection status of medical workers and found that the rate of positive TB-IGRA results was higher among high risk group than in low risk group. Working environment, occupational history and work type were risk factors for TB infection in hospital. This study also found that high risk group had higher IFN-γ expression and a lower ratio of CD4+ to CD8+ T cells and further analysis found that this immune disorder is associated with wards and occupations. Conclusions This study through rigorous sample collection and analysis found the risk factors of latent tuberculosis infection in health care workers. This finding may provide a theoretical basis to be used by the countries with a high TB burden to further improve their strategies for the prevention of TB infections in hospitals and may give an indication for improving the personal health of medical staff in infectious disease hospitals.