Methods for separation, characterization and/or identification of microorganisms using spectroscopy

A method of characterizing and/or identifying an unknown microorganism from a test sample, comprising:

• (a) obtaining a test sample known to contain or that may contain an unknown microorganism;
• (b) selectively lysing non-microorganism cells that may be present in said test sample to produce a lysed sample;
• (c) layering said lysed sample on a density cushion in a container, wherein said density cushion has a homogeneous density;
• (d) centrifuging said container to separate said unknown microorganism from other components of said lysed sample, said unknown microorganism passing through said density cushion to form a microorganism pellet at the bottom of said container;
• (e) spectroscopically interrogating said pellet in situ to produce an excitation/emission matrix (EEM) of said unknown microorganism, wherein said spectroscopic interrogation comprises intrinsic fluorescence in front face mode;
• and
• (f) characterizing and/or identifying said unknown microorganism in said pellet by comparison of the excitation/emission matrix with spectroscopic measurements taken, or spectroscopic properties predicted, of known microorganisms.