Vibrational Spectroscopy of Intact Microorganisms and of Microbial Biofilms

PETER LASCH; MAREN STÄMMLER; CHRISTOP SCHAUDINN; CECILIA BEATRIZ FÍGOLI; ALEJANDRA BOSCH

Victoria

Conferencia; ICAVS 2017 9th International Conference on Advanced Vibrational Spectroscopy; 2017

International Conference on Advanced Vibrational Spectroscopy

Vibrational Spectroscopy of Intact Microorganisms and of Microbial Biofilms Vibrational spectroscopic techniques like infrared (IR) and Raman spectroscopy are emerging generic technologies suitable for rapid and reliable characterization of pathogenic microorganisms [1,2]. All these techniques have in common that they can be used to obtain taxon-specific biomarker profiles suitable for bacterial identification at the genus, species, or even at the subspecies level holding the potential to serve as rapid and sensitive identification techniques in clinical or food microbiology and for the detection of biosafety level (BSL)-3 microorganisms. Whilst mass spectrometry applications always require cultivation of the pathogens, vibrational microspectroscopic techniques such as confocal Raman microspectroscopy (CRM), FTIR microspectroscopy and nearfield IR spectroscopy are also capable of characterizing individual microbial cells. Vibrational microspectroscopic techniques allows thus for the rapid and sensitive characterization of microorganisms without the need for cultivation, and without the requirement of tagging, labeling or staining. It is now an accepted standard that vibrational spectra of complex biomedical samples such as intact microbial cells should be considered as spectral fingerprints which cannot be always completely understood in an analytical sense. It is advantageous to analyze the spectral data by pattern recognition techniques, preferentially of the supervised type. As the concept of supervised classification requires a teaching phase in which labeled subsets of reference spectra are analyzed, the compilation and validation of the teaching spectra will be the main challenge to render vibrational spectroscopy-based expert systems applicable in practice. In the second part of the presentation we will introduce confocal Raman microspectroscopy as an evolving technique for studying genetically homogeneous microbiological samples, which may exhibit heterogeneous multi-component systems. Because of the capability to study individual microbial cells, Raman microspectroscopy and Raman imaging offer possibilities to new shed light on the role of the cell?s divisional or metabolic state in creating heterogeneity on the phenotypic level. [1] Lasch, P. and D. Naumann, Encyclopedia of Analytical Chemistry, 2015. [2] Huang, W. E., Li, M., Jarvis, R. M., Goodacre, R., Banwart, S. A., Adv Appl Microbiol, 2010. 70:153-86.[3]Martina, P., Bettiol, M. Vescina, C. Montanaro, P. ..., BoschA.; J Clin Microbiol, 2013. 51(1): 339-344.