A method for detecting and characterizing a microorganism in a clinical sample includes introducing a clinical sample to a first culture vessel containing the culture medium; removing a test aliquot; separating DNA from the test aliquot; and performing nucleic acid tests on the DNA to identify the microorganism and to detect the presence or absence of one or more genetic antimicrobial resistance markers in the microorganism. If a microorganism is identified, an antimicrobial susceptibility test is performed wherein microbial growth in the antimicrobial susceptibility test is monitored by accessing growth or markers for growth and wherein the type and concentration of antimicrobial agents used in the antimicrobial susceptibility test is determined by the identity of the microorganism and the antimicrobial resistance markers detected. A device for performing the method is also provided.