Abstract: A method of analysing a sample including a microorganism of interest. The method includes exposing the sample to an antimicrobial; after exposing the sample to the antimicrobial, applying an absorption-based and/or scattering-based spectroscopic technique to the sample to obtain spectrum data whose spectral profile has been influenced by exposing the sample to the antimicrobial, wherein applying the absorption-based and/or scattering-based spectroscopic technique to the sample includes irradiating the sample with UV-Vis radiation; obtaining information regarding the susceptibility/resistance of the microorganism of interest to the antimicrobial from the spectrum data. The absorption-based and/or scattering-based spectroscopic technique may be applied to the sample no more than 60 minutes after the initial exposure of the sample to the antimicrobial.