TABLE 1.

Definitions of bloodstream infection and associated entities

Entity	Definition
Contamination of blood cultures	Blood cultures are positive for growth due to organisms that were not present in the bloodstream
Bacteremia	Presence of viable bacteria in the blood; blood cultures positive for bacterial growth where contamination has been ruled out
Fungemia	Presence of viable fungi in the blood; blood cultures positive for fungal growth where contamination has been ruled out
Transient bacteremia/fungemia	Brief episode of bacteremia/fungemia that is not associated with infection
Bloodstream infection	Bacteremia/fungemia that is associated with infection
Hospital-onset bloodstream infection	Bloodstream infection that is first identified (culture drawn) ≥48 h after hospital admission and within 48 h following hospital discharge
Community-onset bloodstream infection	Bloodstream infection occurring in an outpatient or first identified (culture drawn) <48 h following admission to hospital
Health care-associated community-onset bloodstream infection	Community-onset bloodstream infection associated with significant prior health care exposure (as evidenced by recent hospitalization, specialized in-home medical services, care in a hospital-based clinic or hemodialysis unit, or residence in a nursing home)
Community-associated community-onset bloodstream infection	Community-onset bloodstream infection not fulfilling criteria for health care-associated infection
Polymicrobial bloodstream infection	Episode of bloodstream infection associated with two or more different organisms isolated within 48 h of each other