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Updated: Sep 14, 2025
Preparation of Mycobacterium Tuberculosis Culture Filtrate to Understand TB Pathogenesis
Published on: March 28, 2025
A method for purifying and concentrating Mycobacterium tuberculosis in sputum specimens: The double-membrane
Dingyi Liu1, Wenjing Wang1, Yue Hou1
1Translational Medicine Center, Beijing Chest Hospital, Capital Medical University, Beijing 101149, China.
Background:
Tuberculosis (TB) is an infectious disease that poses a global hazard to public health. Clinically, the small number and low concentration of Mycobacterium tuberculosis (M.tb) in some specimens make TB difficult to detect in the laboratory and affect the sensitivity of diagnosis.
Methods:
M.tb in clinical sputum specimens was purified and concentrated using the double membrane filtration concentration method (DMFCM), which was compared with existing methods and evaluated for application.
Results:
DMFCM removes 40-80% of impurities from 80.53% of specimens while concentrating M.tb by up to 3.366 times. In microscopy examination, compared with the direct smear method (DSM), the sensitivity with DMFCM of the test was increased from 58.33% to 73.61%. For quantitative real-time PCR (qPCR), the positive rate of the sputum specimens treated with the DMFCM (37/42) was higher than that treated with centrifugation (35/42). In terms of cultures, treatment of sputum specimens with DMFCM reduced the time required to determine a positive result to 75% of the time required compared to the MGIT 960 liquid cultures, and increased the rate of positivity.
Conclusions:
The M.tb in the culture solution after DMFCM treatment is purer and more concentrated, which can effectively improve the positive rate of detection.
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