This disclosure provides a method for detecting and / or identifying uncultured bacteria. The sample is an aerosol sample selected from a group consisting of cough, sneeze, saliva, mucus, bile, urine, vaginal secretions, middle ear aspirate, pus, pleural effusions, synovial fluid, abscesses, cavity swabs, serum, blood and spinal fluid. The method comprises obtaining absorption spectra (AS) of the sample, extracting and processing the acquired data, thereby detecting and / or identifying the bacteria.