Klebsiella and Serratia Infections: A Quick Fact Sheet

Serratia marcescens under a microscope

The biggest news this week has been the deadly bacterial outbreak at two of the country’s major hospitals, which has claimed the lives of 18 babies. The bacteria have been identified as klebsiella and serratia.

Below is a quick fact sheet:


According to the US-based Centers for Disease Control and Prevention (CDC), Klebsiella is a type of Gram-negative bacteria that can cause different types of infections, including pneumonia, bloodstream infections, wound or surgical site infections, burns and meningitis. The bacteria are normally found in the human intestines, where they do not cause disease in healthy individuals. They are also found in human stool. Infection most often occurs in hospitals and other healthcare facilities, commonly among sick patients who are receiving treatment for other conditions. Those most at risk for Klebsiella infection are patients who requires devices such as ventilators or catheters, and those taking long courses of certain antibiotics.


Serratia is also a type of Gram-negative bacteria and is actually a part of the Klebsielleae species. These bacteria are usually found in the respiratory and urinary tracts in adults. Serratia can cause infections of the bloodstream, lower respiratory tract, urinary tract, surgical wounds, and skin and soft tissues in adult patients, as well as meningitis, wound infections, and arthritis have occurred in children.


Typically, Klebsielleae must enter the respiratory tract to cause pneumoniae, or the blood to cause a bloodstream infection.

In healthcare settings, Klebsielleae bacteria can be spread through person-to-person contact (for example, from patient to patient via the contaminated hands of healthcare personnel, or other persons) or, less commonly, by contamination of the environment.


According to msdmanuals.com, this severe infection typically causes cough, with the patient bringing up a sticky, dark brown or dark red sputum, and collections of pus (abscesses) in the lung or in the membrane between the lungs and chest wall (empyema).


Klebsiella and Serratia infections are diagnosed with an examination and culture of a sample of infected tissue. To confirm the diagnosis, doctors take a sample of sputum, lung secretions (obtained through a bronchoscope), blood, urine, or infected tissue. The sample is stained with Gram stain, cultured, and examined under a microscope. These bacteria can be readily identified.

Other tests depend on the type of infection. They may include imaging tests, such as ultrasonography, x-rays, and computed tomography (CT).

Bacteria identified in samples are tested to determine which antibiotics are likely to be effective (a process called susceptibility testing).


Infection is treated with antibiotics, given intravenously. Klebsiella and Serratia infections are difficult to treat because bacteria acquired in health care facilities are usually resistant to many antibiotics. If a Klebsiella infection is acquired outside of a health care facility, antibiotics, usually a cephalosporin (bactericidal agents) or fluoroquinolone (commonly used to treat a variety of illnesses such as respiratory and urinary tract infections), given intravenously, can cure it.


To prevent spreading Klebsiella infections between patients, healthcare personnel must follow specific sanitation and infection control precautions. These precautions may include strict adherence to hand hygiene and wearing gowns and gloves when they enter rooms where patients with Klebsiella–related illnesses are housed.

To prevent the spread of infections, patients also should clean their hands very often, including:

  • Before preparing or eating food
  • Before touching their eyes, nose, or mouth
  • Before and after changing wound dressings or bandages
  • After using the restroom
  • After blowing their nose, coughing, or sneezing
  • After touching hospital surfaces such as bed rails, bedside tables, doorknobs, remote controls, or the phone