A bloodstream infection (BSI) occurs when bacteria or other pathogens enter the bloodstream, leading to serious health complications. This can happen through various routes, such as infections in other parts of the body, medical procedures, or the use of intravenous lines. Symptoms may include fever, chills, rapid heartbeat, and confusion. If left untreated, bloodstream infections can progress to severe conditions like sepsis, which is a life-threatening response to infection. Diagnosis typically involves blood cultures to identify the causative agent, and treatment usually requires antibiotics or other medications to eliminate the infection and support the patient's recovery.