| Objective:To investigate the volatile organic compounds biomarkers or profiles of Mycobacterium tuberculosis complex(MTC) by mass spectrometry analysis and to determinate the clinical value in TB diagnosis and differential diagnosis.Methods:The head space of Mycobacterium tuberculosis complex cultures and MTC-related genus which could cause false detection, such as Nontuberculosis mycobacteria, Nocardia, Rhodococcus, Streptomyces, Rothia dentocariosa cultures,were detected by Surface desorption atmospheric pressure chemical ionization-Mass spectrometry(SDAPCI-MS) to identify MTC-specific VOCs biomarkers, as well as clinical isolates of some common bacterial and fungus pathogens. The identification of potential biomarker was based on comparison of the collision induced dissociation(CID) spectrum of standard substance. Principal component analysis(PCA) to evaluated the differences and similarities of VOCs fingerprints between genus.Results:Visible differences in the TICs were clearly observed between MTC and all other genus bacterial and fungus. PCA demonstrated significant discrimination between all the MTC strains and revealed species specific VOCs profiles. We have identified the methyl nicotinate as MTC specific volatile compounds, which was detectable before the visual appearance of colonies. The m/z 140 and m/z 152 were significantly higher than any other genus(P<0.01, Fisher exact test). Shared compounds such as 2-phenylethanol(m/z 122), ethyl formate(m/z 74), Acide propano?que(m/z 76) and benzoic acid(m/z 108), are seen to be common to the headspace above the bacteria cultures.Conclusion:SDAPCI-MS detect the microbial VOCs pattern–fingerprints of cultured organisms for rapidly identification and classification Mycobacterium tuberculosiscomplex, and we have demonstrated the methyl nicotinate as a TB marker, all these can be used for assessing the association with TB. |
