An increase of healthcare-associated infections caused by multidrug- resistant organisms (MRDO) is currently observed. One of the main causes of the emergence of a MDRO infection is an overuse of antibiotics. Therefore, saving useless antibiotic treatment is currently a priority from a public health point of view. The evaluation of the risk of having a bloodstream infection will allow both activating faster treatment decisions (when the risk is significantly high) or to save useless resources in terms of diagnostic tests and treatments, also limiting the potential for side effects (when the risk is significantly low).

Inclusion Criteria:

1. adult patients hospitalized at the Gemelli Polyclinic Foundation
2. having at least one performed blood culture
3. starting an antibiotic therapy

Exclusion Criteria:

1. blood cultures with contaminants
2. <18 years old
3. died after less than 48 hours from blood cultures positivity

adult patients hospitalized at the Gemelli Polyclinic Foundation