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Medical Author:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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In this Article

• Meningococcemia facts
• What is meningococcemia?
• What causes meningococcemia?
• What are risk factors for meningococcemia?
• What are symptoms and signs of meningococcemia?
• How is meningococcemia diagnosed?
• What is the treatment for meningococcemia?
• What is the prognosis of meningococcemia?
• Can meningococcemia be prevented?
• Where can people find more information on meningococcemia?
• What research is being done on meningococcemia?
• Meningococcemia Index

Meningococcemia is a bacterial infection of the blood due to Neisseria meningitidis. This bacterium is most famous for causing meningococcal meningitis which may also be present in meningococcemia. Bloodstream infections are sometimes called "blood poisoning" or septicemia. Many bacteria can cause bloodstream infections including staphylococci, Streptococcus B, or Streptococcus A. In addition, other bacteria can cause meningitis, including Streptococcus pneumoniae or leptospirosis. However, N. meningitidis is concerning because it is more contagious than these other bacteria and typically infects older children and adolescents.

Picture of Neisseria meningitidis seen under the microscope; SOURCE: CDC/Dr. Brodsky

As mentioned, the bacterium that causes meningococcemia is called N. meningitidis, also known as "meningococcus." Meningococcemia may also be called meningococcal bacteremia. Under the microscope, the bacteria may appear in pairs, looking like two small kidney beans side by side. N. meningitidis is surrounded by a capsule made of complex carbohydrates called polysaccharides. These polysaccharides stimulate the immune system, which helps the body fight the infection. There are several different types (serogroups) of meningococci. Most human disease is caused by serogroups A, B, C, Y, and W135. Bacteria from other serogroups are called "nonpathogenic," meaning that they do not cause disease.

Transmission of N. meningitidis is from person to person through respiratory secretions. Some people can harbor the bacteria in their throats and not get sick, which is called a "carrier" state. In others, the bacteria rapidly invade the tissues and bloodstream, causing disease.