Bloodstream infection
Infection of blood by bacteria, often leading to sepsis.
Bloodstream infections (BSIs) are infections of blood caused by blood-borne pathogens. The detection of microbes in the blood, most commonly accomplished by blood cultures, is always abnormal. A bloodstream infection is different from sepsis, which is characterized by severe inflammatory or immune responses of the host organism to pathogens.
- field
- Infectious disease
- known_for
- Infection of blood by bacteria, often leading to sepsis
- common_causes
- Pneumonia, meningitis, surgery, catheters, intravenous drug abuse
- diagnosis
- Blood culture
- treatment
- Antibiotics
Lore & Background
Bacteria can enter the bloodstream as a severe complication of infections like pneumonia or meningitis, during surgery involving mucous membranes, or due to catheters and other foreign bodies. Transient bacteremia can result after dental procedures or brushing of teeth. Gram positive bacteria such as Staphylococcus aureus are the most common cause of healthcare-associated bacteremia in North and South America, while E. coli is the most common cause of community-acquired bacteremia, often from urinary tract infections.
Reader's Guide
Bloodstream infections are significant because they can lead to sepsis, septic shock, and multiple organ dysfunction syndrome, which are potentially fatal if not treated quickly. Bacteria can also spread via the blood to other parts of the body, causing endocarditis, osteomyelitis, or meningitis. Treatment is with antibiotics, and prevention with antibiotic prophylaxis can be given in high-risk situations. The diagnosis relies on blood cultures, with careful sterile technique to avoid contamination. Gram negative bacteria account for about 24% of healthcare-associated and 45% of community-acquired cases, with higher morbidity in the elderly.
Did You Know?
- Staphylococcus aureus is the most common cause of healthcare-associated bacteremia in North and South America.
- E. coli causes approximately 75% of community-acquired bacteremia, usually from a urinary tract infection.
- Transient bacteremia can occur after eating, toothbrushing, or flossing due to viridans streptococci.
- Gram-negative bacteremia occurs more frequently in elderly populations (65 years or older).
Frequently Asked Questions
What is Bloodstream infection?
Bloodstream infection refers to the presence of pathogenic microorganisms circulating in the blood, which is always an abnormal finding. It is most frequently caused by bacteria and can progress to sepsis if left untreated.
What are the common causes of Bloodstream infection?
Typical triggers include pneumonia, meningitis, surgical procedures, indwelling catheters, and intravenous drug use. These factors allow bacteria to breach normal barriers and enter the circulatory system.
How do you diagnose Bloodstream infection?
The gold-standard diagnostic tool is a blood culture, which detects microorganisms growing in a sample of the patient's blood. Any positive blood culture is considered abnormal and warrants immediate clinical attention.
How is Bloodstream infection treated?
The primary treatment is targeted antibiotic therapy to eliminate the circulating bacteria. Prompt administration is critical to prevent progression toward sepsis or multi-organ failure.
What's the difference between Bloodstream infection and Sepsis?
A bloodstream infection is the presence of pathogens in the blood itself, while sepsis is the host's severe inflammatory or immune response to those pathogens. In short, BSI is the invasion; sepsis is the body's overreaction to it.
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