Colorimetric Sensor Array Allows Earlier Detection and Simultaneous Identification of Sepsis-

28 29 Sepsis is a medical emergency demanding early diagnosis and tailored antimicrobial therapy. 30 Every hour of delay in effective therapy measurably increases mortality. Blood culture is currently the 31 reference standard for diagnosing bloodstream infection, a multistep process which may take one to 32 several days. Here, we report a novel paradigm for earlier detection and simultaneous identification of 33 pathogens in spiked blood culture by means of a metabolomic “fingerprint” of the volatile mixture 34 outgassed by the organisms. The colorimetric sensor array provided significantly faster detection of 35 positive blood cultures than a conventional blood culture system (12.1 hours vs. 14.9 hours, p < 36 0.001), while allowing identification of 18 bacterial species with 91.9% overall accuracy within 2 37 hours of growth detection. The colorimetric sensor array also allowed discrimination between 38 unrelated strains of methicillin-resistant Staphylococcus aureus, indicating that the metabolomic 39 fingerprint has potential to track nosocomial transmissions. Altogether, the colorimetric sensor array 40 is a promising tool that offers a new paradigm for diagnosis of bloodstream infection. 41