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Meningitis - gram-negative


Gram-negative meningitis is a bacterial infection of the membranes covering the brain and spinal cord (meninges). The bacteria turn pink when exposed to a special stain (Gram-negative bacteria).

Alternative Names:

Gram-negative meningitis


Acute bacterial meningitis can be caused by Gram-negative bacteria.

Meningococcal and H. influenzae meningitis are caused by Gram-negative bacteria and are covered in detail in other articles. This article covers Gram-negative meningitis caused by the following bacteria:

  • Escherichia coli
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Serratia marsescens

Gram-negative meningitis is more common in infants than adults. But it is also important in adults, especially those with one or more risk factors. Risk factors in adults and children include:

  • Fever and chills
  • Mental status changes
  • Nausea and vomiting
  • Sensitivity to light (photophobia)
  • Severe headache
  • Stiff neck (meningismus)
  • Symptoms of a bladder, kidney, intestine, or lung infection

Other symptoms that can occur with this disease:

  • Agitation
  • Bulging fontanelles in infants
  • Decreased consciousness
  • Poor feeding or irritability in children
  • Rapid breathing
  • Unusual posture, with the head and neck arched backwards (opisthotonos)
Exams and Tests:

The doctor or nurse will examine you. This will usually show:

  • Fast heart rate
  • Fever
  • Mental status changes
  • Stiff neck

If the health care provider thinks you may have meningitis, a lumbar puncture (spinal tap) should be done to remove a sample of spinal fluid (cerebrospinal fluid, or CSF) for testing.

Other tests that may be done include:

This list is not all-inclusive. 


Antibiotics should be started as soon as possible. Ceftriaxone, ceftazidime, and cefepime are the most commonly used antibiotics for this type of meningitis. Other antibiotics may be used, depending on the type of bacteria.

If you have a spinal shunt, it may be removed.

Outlook (Prognosis):

The earlier treatment is started, the better the outcome.

Many people recover completely, but a large number of people have permanent brain damage or die from this type of meningitis. Young children and adults over age 50 have the highest risk of death. How well you do depends on:

  • Your age
  • How quickly the infection is treated
  • Your overall health
Possible Complications:
When to Contact a Medical Professional:

Call the local emergency number (such as 911) or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:

  • Feeding problems
  • High-pitched cry
  • Irritability
  • Persistent unexplained fever

Call the local emergency number if you develop any of the serious symptoms listed above. Meningitis can quickly become a life-threatening illness.


Prompt treatment of related infections may reduce the risk of meningitis.


Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 360.

Thigpen MC, Whitney CG, Messonnier NE, et al. Emerging Infections Programs Network. Bacterial meningitis in the United States, 1998-2007. N Engl J Med. 2011 May 26;364:2016-2025.

Tunkel AR, Van de Beek D, Scheld WM. Acute meningitis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 84.

Review Date: 8/31/2014
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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