Abstract: Objective To investigate the characteristics of the distribution of polluting bacteria in the sputum growing medium used for BACTEC which from pulmonary department patients,so we can do much better in controlling pollution and reduce the pollution ratio.Methods There were 650 sputum samples by means of BACTEC which were from pulmonary department patients between Oct.97 and Jan.99.To evaluate the polluted sputum samples in these 650 samples in normal way of bacterial culture and analyse the results.Results In the 650 samples,43 cases were polluted,total pullotion rate was 6.6%(43/650).To evaluate in normal way of bacterial culture,the 43 polluted samples and got 12 kinds of strain.There were 2～3 kinds of strain from every one of 4 samples.So 48 strain were got.Mainly of B.subticis and M.agilis.16(33.3%) and 9(18.8%) respectively.The other were 6(12.5%) strains of S.aureus;3(6.2%) strains of C.albicans and 14(29.2%) strains of gram-negative bacilli.The gram-negative bacilli can be divided into 7 kinds of bacterias.Conclusion (1)Laboratory pollution is the main pollution source.Non-bacteria operation must be strictly controlled.(2)The gram-negative bacilli,S.aureus and C.albicans were 47% (23/48).This may be related to the pulmonary infection and pathogenic bacteria in the mouth and pharynx [1].We suggest to increase the control of the pulmonary inflammation in clinic.

Key words: M.tuberculosis, Polluted ratio