Abstract: Objective  To assess the risk of aerosol transmission of Mycobacterium in the air of the wards of tuberculosis (TB) inpatient in TB hospital. Methods  134 air samples were collected from the air of 22 wards housing sputum smear-positive patients in TB hospital by using the microbial aerosols liquid percussive sampler (FA-1 type air sampler). The air samples were digested and depolluted by NALC-NaOH, then inoculated in L-J culture medium and BacT/ALERT 3D culture system, respectively. The culture-recovery samples were identified by Ziehl-Neelsen staining and DNA sequencing. The Mycobacterium culture-recovery rates of L-J culture and BacT/ALERT 3D culture were compared and statistically analyzed using chi-square test of paired comparison (significance level α=0.05). Results  Of 134 air samples, 3 samples were culture-recovery, and identified respectively as M. tuberculosis, M. intracellulare and M. gordonae by gene sequencing. For BacT/ALERT 3D culture, 2 samples were conta-minated, and its culture-recovery rate was 2.3% (3/132). For L-J culture, 1 sample was contaminated, and its culture-recovery rate was 1.5% (2/133). There was no significant difference between these two methods (χ²=0.00，P>0.05).  Conclusion  Mycobacterium existed in the wards of sputum smear-positive TB inpatient in TB hospital. Surveying termly the air of TB hospital is an important measure to prevent and control the nosocomial infection.

Key words: Tuberculosis,pulmonary, Mycobacterium, Air, Cross infection, Shanghai city