Vibrational spectroscopy of microorganisms: A review

Vibrational spectroscopic methods, mid- and near-infrared, and Raman spectroscopies, have been extensively applied to the study of microorganisms. This is due to the relatively rapid analysis time, relative low-cost, experimental flexibility, and phenotypic nature of these methods. Consequently, vibrational spectroscopies have been investigated for clinical, environmental and industrial microbiology applications. This review outlines the principles of mid- and near-infrared, and Raman spectroscopies, and steps through vibrational spectroscopic experiments in the context of microbiological studies. Further applications within species/strain identification, antimicrobial resistance, bioremediation, cell sorting and intracellular microbial protein analysis are examined. Vibrational spectroscopy is expected to become increasingly routine in microbial analyses, particularly in clinical settings, driven by the harmonisation of spectral databases, the expanding application of deep learning methods and improved instrumentation to reduce sampling-to-reporting time.