What Is The Difference Between Bacteremia And Septicemia?

Bacteremia and septicemia are two technical medical terms that can often be misunderstood or misused, even by medical professionals.

What Is The Difference Between Bacteremia And Septicemia?

This is not a concern as these two terms are simply definitions rather than having any significant influence on management or treatment.

The terms bacteremia and septicemia are most commonly found in research papers, rather than in medical dialogue. 

However, it is still worth developing a clear understanding of the terms and the differences between them to correctly understand their uses and implications.


Bacteremia is simply defined as the presence of bacteria in the blood. When bacteremia is present, there is not a high level of bacteria that is detected in the blood, and the condition itself is not usually dangerous.

In bacteremia, toxins are not produced or released into the bloodstream. Cases of bacteremia can become serious or develop into a blood infection with more serious complications.


There are a few ways in which bacteremia can be caused. The most common ways for bacteremia to develop are through an open wound, an infection, or via injections and surgical procedures.

In most cases, bacteremia develops when the blood is exposed to outside contaminants, mostly through direct contact or airborne cells.  

Common situations in which bacteremia can occur include, but are not limited to, dental procedures such as extractions, medical devices such as catheters, severe burns, and injuries, and the spread of infection from another part of the body. 

Bacteremia is caused by a variety of different bacteria, some examples of which include, E. Coli, MRSA, Salmonella, Pneumococcal bacteria, and Group A Streptococcus bacteria. 


In many cases, bacteremia is symptomless. In these cases, the immune system is able to adequately fight the infection and clear it without external, medical intervention.

This is known as asymptomatic bacteremia, and patients will often not be aware that they have the infection.  

In cases where bacteremia does have symptoms, sufferers will likely experience a mild fever including chills and shaking or shivering.

In cases that produce symptoms, some level of medical intervention or treatment may be required if the immune system is not successfully clearing the infection. 


In order to make a solid, accurate diagnosis of bacteremia, a blood culture must be performed. A general blood screening should be enough to diagnose the infection, however, there are cases in which a doctor may opt to order additional tests.

Additional tests may include X-rays, CT scans, or Ultrasounds, all of which may be used to detect sites of infection within the body. 


Once a diagnosis of bacteremia has been made, the main treatment is antibiotics.  Antibiotics may be necessary in cases of bacteremia to avoid the development of more serious blood infections.  

If treatment is deemed necessary, broad-spectrum antibiotics will be prescribed first, these are often administered via IV.

Once an antibiotic sensitivity test has been performed, a more specific antibiotic can be prescribed to tackle the infection more quickly.  

Antibiotic courses for bacteremia usually last 1-2 weeks. 



Septicemia, otherwise known as blood poisoning, is a term that you are unlikely to hear used in a medical setting, or read in recent research as it is considered to be an obsolete term.

The more common term is sepsis, or sometimes septic shock. Septicemia refers to the presence and multiplication of bacteria in the blood and is often the precursor to full sepsis.

Septicemia is a potentially life-threatening infection of the blood and as such, suspected cases should be taken very seriously. 

In suspected cases of septicemia, it is imperative that medical assistance is sought or provided with appropriate urgency.


Septicemia often develops as a result of infection already present within the body.

Infections of the lungs such as pneumonia, infections of the abdomen such as peritonitis, and infections of the urinary tract such as internal cystitis can all develop into septicemia.  

The most common type of bacteria that causes septicemia is Staphylococci, thought to be responsible for over 50% of all septicemia cases.

Other bacteria that may cause a septicemia infection include, Streptococcus pyogenes, Klebsiella, and Pseudomonas aeruginosa.

In cases where precursor infections are treated appropriately, effectively, and promptly the risk of developing septicemia is significantly reduced.


When septicemia does develop within the body, it is rarely asymptomatic. The most common symptoms to look for in suspected septicemia cases include prostration, chills, fever, shivering and shaking, fast respiration, and an increased heart rate.

It is not necessary for all of these symptoms to be present in septicemia cases and any of the symptoms should be taken seriously where there is a risk of sepsis.


The diagnosis of septicemia is very similar to that of bacteremia. A doctor will order any of the following tests: blood culture, bloody oxygen levels, blood count, blood clotting factor, urine tests, and occasionally a chest x-ray. 


Treatment is key in promoting a favorable outcome in cases of septicemia.  If left untreated, septicemia will develop into sepsis which can be incredibly serious and even life-threatening.

Once a diagnosis of septicemia has been established, a course of antibiotics will be prescribed to treat the underlying bacterial infection that is causing the septicemia. IV fluids may also be used to help aid recovery and keep the patient hydrated.

The Difference Between Bacteremia And Septicemia

While bacteremia and septicemia are both infections of the blood, there are a few differences between them. One of the main differences is the behavior of the bacteria that is present in the blood.

In bacteremia, the bacteria is simply present in the blood, whereas, in septicemia, the bacteria actively multiply in the blood.  

In general, bacteremia is a milder infection than septicemia and can often be dealt with by the immune system without producing any symptoms. Septicemia, however, requires medical treatment to be resolved and produces multiple symptoms. 

Jennifer Dawkins

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