Rapid Identification of Mycobacteria by Raman Spectroscopy

• Published in: Journal of Clinical Microbiology 2008-03, Vol.46 (3), p.961-965
• Main Authors: Buijtels, P.C.A.M, Willemse-Erix, H.F.M, Petit, P.L.C, Endtz, H.P, Puppels, G.J, Verbrugh, H.A, van Belkum, A, van Soolingen, D, Maquelin, K
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Hot Temperature; Humans; Microbiology; Miscellaneous; Mycobacteriology and Aerobic Actinomycetes; Mycobacterium - classification; Mycobacterium - genetics; Mycobacterium - growth & development; Mycobacterium - isolation & purification; Mycobacterium Infections - diagnosis; Mycobacterium Infections - microbiology; Mycobacterium tuberculosis; Mycobacterium tuberculosis - classification; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - growth & development; Mycobacterium tuberculosis - isolation & purification; Reproducibility of Results; RNA, Ribosomal, 16S - genetics; Sensitivity and Specificity; Sequence Analysis, DNA; Species Specificity; Spectrum Analysis, Raman - instrumentation; Spectrum Analysis, Raman - methods; Time Factors; Tuberculosis - diagnosis; Tuberculosis - microbiology
• ISSN: 0095-1137; 1098-660X; 1098-5530
• DOI: 10.1128/JCM.01763-07

A number of rapid identification methods have been developed to improve the accuracy for diagnosis of tuberculosis and to speed up the presumptive identification of Mycobacterium species. Most of these methods have been validated for a limited group of microorganisms only. Here, Raman spectroscopy was compared to 16S rRNA sequencing for the identification of Mycobacterium tuberculosis complex strains and the most frequently found strains of nontuberculous mycobacteria (NTM). A total of 63 strains, belonging to eight distinct species, were analyzed. The sensitivity of Raman spectroscopy for the identification of Mycobacterium species was 95.2%. All M. tuberculosis strains were correctly identified (7 of 7; 100%), as were 54 of 57 NTM strains (94%). The differentiation between M. tuberculosis and NTM was invariably correct for all strains. Moreover, the reproducibility of Raman spectroscopy was evaluated for killed mycobacteria (by heat and formalin) versus viable mycobacteria. The spectra of the heat-inactivated bacteria showed minimal differences compared to the spectra of viable mycobacteria. Therefore, the identification of mycobacteria appears possible without biosafety level 3 precautions. Raman spectroscopy provides a novel answer to the need for rapid species identification of cultured mycobacteria in a clinical diagnostic setting.