What is Gram-Negative Sepsis?

Sepsis is a medical condition in which the entire body experiences inflammation as it tries to fight off an infection that has made its way into the bloodstream. Gram-negative sepsis is the result of a Gram-negative bacterial infection. It is a potentially life-threatening condition that most commonly affects young children and older adults.

Gram-negative bacteria derive their name from their appearance following a staining procedure under a microscope. Bacteria that do not react to a stain called crystal violet are considered to be Gram-negative. That lack of reaction to the staining indicates the type of membrane the organisms possess.

Gram-negative bacteria have a cell membrane that contains lipopolysaccharide, which the body rejects as part of an immune reaction. This produces an inflammatory response as the body’s cells react to fight infection. Sepsis occurs when these immunity cells become over-activated, causing widespread body response.

Gram-negative sepsis produces a change in temperature as the body tries to compensate, and patients may have a fever or hypothermia. This can result in chills, an increased heart rate, and a faster breathing rate. Laboratory changes show either a high or low count of white blood cells, the cells that help the body fight off infection. Sepsis eventually may begin to affect organ function, causing symptoms of mental confusion or impaired kidney function.

Sepsis can lead to septic shock, which often causes death. As symptoms of sepsis affect the organs, overall blood pressure may fall, requiring extra intravenous fluids to maintain perfusion. During septic shock, the body may not respond to extra fluids, resulting in the heart’s inability to provide adequate amounts of oxygenated blood to the tissues.

Gram-negative sepsis may be treated with antimicrobial therapy to help fight the bacteria causing the infection. Early detection and treatment are important to reduce the risk of septic shock. Doctors often diagnose infection through a blood culture, in which a sample of blood is monitored in the lab for growth of microorganisms. Blood cultures may take up to 72 hours to produce results, so treatment with antibiotics can be initiated during the time it takes to specifically identify the Gram-negative organism. Some types of Gram-negative bacteria that can cause infection and sepsis include Escherichia coli (E. coli), Klebsiella and Pseudomonas aeruginosa.

Beyond antimicrobial therapy and intravenous fluids, other measures may be necessary to treat Gram-negative sepsis. Medications to raise blood pressure are warranted if a patient does not respond to an increase in fluids. Some types of steroids may also be used to reduce inflammation. If a patient develops breathing difficulty because of decreased lung function, use of a ventilator may be required. A combination of therapies is often necessary to reduce the damaging effects.

People who have certain conditions are at greater risk of developing Gram-negative sepsis, including those who have low levels of immunity and those with traumatic injuries such as burns. Patients who have used large amounts of broad-spectrum antibiotics to treat other infections may be prone to developing sepsis. Additionally, age is a factor and sepsis more commonly affects babies and the very old.