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Bacteremia is the presence of bacteria in the bloodstream.

Most bacteremia is temporary, has no symptoms, and will usually not lead to serious infection. However, bacteremia can also lead to serious infections. The risk is highest in those with weakened immune systems. Bacteremia that causes symptoms requires treatment to prevent more severe infections.


Bacteria are normally present in certain areas of the body. For example, it can be found on the skin and inside the mouth, nose, throat, large intestine, and vagina. Small tears or damage in these tissue can allow the bacteria to enter the bloodstream. This can happen during everyday activities, like vigorous toothbrushing, or certain medical procedures. Bacteremia may also be caused by an infection that is already in the body, such as pneumonia, urinary tract, or ear infection.

Once bacteria enters the blood, the immune system will normally remove it. The quick removal of bacteria will stop other infections from developing. Complications of bacteremia usually develop if:

  • Bacteria remain in the bloodstream for long period of time
  • Large amounts of bacteria in the blood overwhelm the immune system
  • The immune system is weakened by medical conditions, treatments, or procedures

This can lead to infections anywhere in the body such as lungs, heart, brain, or bone. Growth of the bacteria in the bloodstream can also lead to sepsis, a body wide infection.

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Risk Factors

Certain medical or dental procedures can cause bacteremia. Higher risk activities include:

  • Dental cleaning or procedures
  • Urinary catheter
  • IV or central catheters
  • Tubes placed in throat to assist in breathing—mechanical ventilation
  • Surgical treatment of abscesses or infected wounds
  • Invasive procedures, such as endoscopy or open surgeries
  • Intensive care unit admission

The risk of developing a serious infection from bacteremia is increased with:

  • A suppressed or weakened immune system
  • Exposure to aggressive strains of bacteria
  • Presence of implanted medical devices


Bacteremia symptoms can vary depending on the amount of bacteria present.

  • There may be no symptoms in children with brief small amounts of bacteria.
  • If higher amounts of bacteria enter the system there may be fever without other symptoms .
  • Growth of bacteria in the bloodstream can lead to more general symptoms such as a fever with body aches.
  • Higher growth rates and more severe bacteremia can result in symptoms of sepsis, such as a fast heart rate, low blood pressure, or mental confusion.

Bacteremia can lead to a number of serious complications such as infections of:

Untreated complications can lead to disability, organ failure, and death.


You will be asked about your child’s symptoms and medical history. A physical exam will be done, including specific questions about recent medical treatments or surgery.

Blood tests will be done to see if your body if responding to an infection.

If bacteremia is suspected, a blood culture test will be done to identify the specific bacteria causing the problem. Identifying the specific bacteria may help with treatment decisions.


Bacteremia that is not causing symptoms may not need treatment. The body’s immune system will control and remove the bacteria.

Bacteremia that causes symptoms or infections is treated with antibiotics. The antibiotics may be later adjusted if the blood culture find a bacteria that requires specific antibiotics.

Other symptoms associated with the location of the infection or sepsis will need to be treated.


There are vaccines for some bacteria that can cause serious infection, such as pneumococcal , meningococcal , and haemophilus influenze type B vaccines.

Antibiotics may be recommended before high-risk procedures if a child is at high risk for infection. This includes children with weakened immune systems or medical implants. The antibiotics will eliminate bacteria that enter into the blood before they can cause problems.


Centers for Disease Control and Prevention  http://www.cdc.gov 

Healthy Children—American Academy of Pediatrics  https://www.healthychildren.org 


Caring for Kids—Canadian Paediatric Society  http://www.caringforkids.cps.ca 

Public Health Agency of Canada  http://www.phac-aspc.gc.ca 


Bacteremia. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/infectious-diseases/biology-of-infectious-disease/bacteremia. Updated May 2016. Accessed August 23, 2017.

Bacteremia with gram-negative bacilli. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T905774/Bacteremia-with-gram-negative-bacilli  . Updated November 6 2015. Accessed August 23, 2017.

Early-onset neonatal sepsis. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T901439  . Updated March 6, 2017. Accessed August 23, 2017.

Late-onset neonatal sepsis. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T116619  . Updated August 11, 2017. Accessed August 23, 2017.

Occult bacteremia. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/pediatrics/miscellaneous-infections-in-infants-and-children/occult-bacteremia. Updated November 2015. Accessed August 23, 2017.

Sepsis in children. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T326289/Sepsis-in-children  . Updated March 20, 2017. Accessed August 23, 2017.

Sepsis treatment in children. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T270047  . Updated July 26, 2017. Accessed August 23, 2017.

Staphylococcus aureus bacteremia. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T905775/Staphylococcus-aureus-bacteremia  . Updated August 12, 2016. Accessed August 23, 2017.

Revision Information

  • Reviewer: EBSCO Medical Review Board Michael Woods, MD, FAAP
  • Review Date: 09/2018
  • Update Date: 10/03/2016