Bloodstream infections (BSIs) are severe diseases associated with a high morbidity and mortality, which increases with the delay until administration of the first appropriate antibiotic (1–8). For this reason, empiric treatments made of broad-range anti-infectious compounds or made of a combination of antimicrobials are started immediately after the sampling of blood bottles. BSIs can be caused by various microorganisms. In the absence of microbiological documentation, physicians suspect a BSI on the basis of clinical symptoms, which trigger the start of empirical treatments. The clinical presentations are multiple and include fever or hypothermia, increases in heart rate, change in inflammatory variable (C-reactive protein, procalcitonin, and white blood cell count increase), and organ failure (2, 9). These symptoms are generally nonspecific and only suggest bloodstream dissemination. Empirical treatments are made of broad-spectrum antibiotics on the basis of the clinical and epidemiological data, but this does not exclude any risk of inappropriate initial treatment.