Abstract: Objective To analyze the contamination and treatment effect of Mycobacterium grow indicate tube (MGIT) liquid culture manual method for the detection of Mycobacterium tuberculosis. Methods A total of 1 088 sputum specimens from patients suspected pulmonary tuberculosis diagnosed preliminary were collected, and all specimens were respectively determined by MGIT method, improved L-J medium base (L-J) method and sputum smear acid-fast staining, and the contamination rates of MGIT method for the first time and after decontamination were compared with those of L-J method. Results In MGIT method for the first time, the contamination rate of smear positive group was 11.24%, that of smear negative group was 7.29%, and the total contamination rate was 7.90%. In L-J method, the contamination rate of smear positive group was 2.96%, that of smear negative group was 3.80%, and the total contamination rate was 3.68%. The corresponding differences were statistically significant (P<0.05). The contamination rate of smear positive group after decontamination was lower than that of smear negative group, there was statistical significance (P<0.05). Conclusions The MGIT method can be used to decontaminate in contaminated culture and reduce the contamination rate, especially smear negative specimens should be adjusted and increased the concentration of digestion time or sterilized agent before pretreatment, in order to control the first time MGIT method′s contamination rate, reduce the number of decontamination, and recommend that clinicians should control the other bacterial infection before leaving specimens for tuberculosis culture.

Key words: Mycobacterium tuberculosis, Mycobacterium grow indicate tube liquid culture manual method, L-T medium base, Contamination , Decontamination