AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Characterization of M. Tuberculosis Lipids in Exhaled TB Bio-aerosols
Robin Wood, Dapeng Chen, Wayne Bryden, CHARLES CALL, Desmond Tutu HIV Research Centre, University of Cape Town
Abstract Number: 77 Working Group: Bioaerosols
Abstract Introduction Tuberculosis (TB) transmission requires expulsion of viable bacteria in respirable aerosols from infected individuals. Detection of infectious individuals depends on exhaled air volume sampled, efficient capture of respirable particles generated from infection sites and sensitive identification of bacterial markers.
Methods Newly diagnosed TB patients remained in a compact personalised clean room for 60 minutes. Airborne particles were collected into liquid using a high flow (300 lpm) cyclone (Coriolis-µ Bertin™), sampling approximately 500 liters of exhaled air. Centrifuged pellets of collected fluid were stained with a novel salvatochromic trehalose probe to identify viable organisms and supernatant was used as substrate for Mycobacterium tuberculosis lipid mass spectrometry (MS) analysis. Lipids were extracted using Folch method and high resolution MS performed with Orbitrap 120,000 mass resolution mass spectrometer (FWHM) in positive and negative ion modes. Signal to noise ratios > 5 and MS/MS analysis enabled accurate mass measurements and identification of unique TB cell wall-associated lipids.
Results For positive ion mode, 3 control, 19 TB, and 14 non-TB samples were included. Principal component analysis distinguished between non-TB and TB samples. However, 4 TB samples were overlapped with non-TB samples. In addition, in positive ion mode, non-TB patients showed small in-group difference while TB samples showed larger in-group differences. For negative ion mode, 3 control, 18 TB, and 17 non-TB samples were included. PCA distinguished non-TB and TB samples but 3 TB samples were over-lapped with non-TB samples. Non-TB and TB showed in-group differences.
Conclusions High-volume liquid cyclone sampling with novel viability staining and mass spectrometry analysis, identified live mycobacteria and specific mycobacterial lipids in TB patient derived bio-aerosols. Characterization of peripheral lung-derived bio-aerosols reflect novel surrogate markers of TB disease.