Abstract: Objective To explore the impact of air-conditions on transmission of M tuberculosis in hospital. Methods The air-samples in the areas with central air-condition, and independent air-condition and no air-condition were collected and incubated in the Lowenstein-Jensen culture medium separately.The air-samples have been cultivated in 36.5℃ for 28 days.Primary distinguish is devised on the shape of the colony on the Lowenstein-Jensen culture medium and the characteristic of the antacid dyeing means. Finally the M tuberculosis was confirmed by a series of the biochemistry tests. Results The detection rate of M.tuberculosis was 31.1% in the area with central air-condition and 15.6% in the area with independent air-condition and 4.4% in the area without air-condition. There were significant differences of the Results in three areas. Conclusion The air-conditions especially the central air-conditions had definite effect on the transmission of M tuberculosis in hospital, and it should be paid necessary attentions.

Key words: M.tuberculosis, Lowenstein-Jensen culture medium, Air-condition