Novel approaches in diagnosing tuberculosis
Date
2011
Authors
Kolk A.H.J.
Dang N.A.
Kuijper S.
Gibson T.
Anthony R.
Claassens M.M.
Kaal E.
Janssen H.-G.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The WHO declared tuberculosis (TB) a global emergency. An estimated 8-9 million new cases occur each year with 2-3 million deaths. Currently, TB is diagnosed mostly by chest-X ray and staining of the mycobacteria in sputum with a detection limit of 1x104 bacteria /ml. There is an urgent need for better diagnostic tools for TB especially for developing countries. We have validated the electronic nose from TD Technology for the detection of Mycobacterium tuberculosis by headspace analysis of 284 sputum samples from TB patients. We used linear discriminant function analysis resulting in a sensitivity of 75% a specificity of 67% and an accuracy of 69%. Further research is still required to improve the results by choosing more selective sensors and sampling techniques. We used a fast gas chromatography- mass spectrometry method (GC-MS). The automated procedure is based on the injection of sputum samples which are methylated inside the GC injector using thermally assisted hydrolysis and methylation (THM-GC-MS). Hexacosanoic acid in combination with tuberculostearic acid was found to be specific for the presence of M. tuberculosis. The detection limit was similar to microscopy. We found no false positives, all microscopy and culture positive samples were also found positive with the THM-GC-MS method. The detection of ribosomal RNA from the infecting organism offers great potential since rRNA molecules outnumber chromosomal DNA by a factor 1000. It thus may possible to detect the organism without amplification of the nucleic acids (NA). We used a capture and a tagged detector probe for the direct detection of M. tuberculosis in sputum. So far the detection limit is 1x106 bacteria / ml. Currently we are testing a Lab-On-A-Chip Interferometer detection system. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Description
Keywords
Electronic nose; GC-MS; hexacosanoic acid; Lab-On-A-Chip Interferometer; sputum; Thermally Assisted Hydrolysis and Methylation; Tuberculosis; tuberculostearic acid, Dot-blot hybridization; Electronic NOSE; GC-MS; hexacosanoic acid; Lab-on-a-chip; sputum; Thermally assisted hydrolysis and methylation; Tuberculosis; Tuberculostearic acids; Alkylation; Artificial organs; Bacteria; Bacteriology; Biometrics; Developing countries; Discriminant analysis; Environmental engineering; Gas chromatography; Hydrolysis; Interferometers; Mass spectrometry; Medicine; Methylation; RNA; Saturated fatty acids; Technology; Detectors
Citation
Proceedings of SPIE - The International Society for Optical Engineering
8029
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959811972&partnerID=40&md5=1732cfa21f2b858af3d384b04adc298a
8029
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959811972&partnerID=40&md5=1732cfa21f2b858af3d384b04adc298a