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Gram-negative Bacterial Infection

Definition

Gram-negative bacteria are bacteria with strong walls. They can cause infections throughout the body. The infections can be serious and tough to treat.

Some gram-negative bacteria can cause certain types of :

  • Food poisoning
  • Infections of the:
    • Stomach and intestines
    • Urinary tract
    • Lungs
    • Blood
  • Meningitis
  • Wound infections
  • Sexually transmitted infections, such as gonorrhea

Development of Pneumonia in the Air Sacs of the Lungs
pneumonia lung fluid

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Causes

Bacteria are normally found in the body. Infections can happen if bacteria:

  • Increase in large amounts
  • Are aggressive
  • Are not kept in check by the immune system

Gram negative bacteria can pass to the body from:

  • Medical devices that pass into the body, such as IVs or catheters
  • Open wounds
  • Contact with someone who carries gram negative bacteria

Risk Factors

Gram negative bacterial infections are most common in hospitals. The risk increases with the length of the stay.

Other things that raise the risk are:

Symptoms

Symptoms depend on the site of the infection. Fever is a common sign.

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done.

An infection may be suspected by the symptoms.

A sample of fluids may be taken from the suspected area. The sample will be tested for bacteria. Samples may be taken with:

  • Blood tests and culture
  • Urine tests and culture
  • Sputum samples
  • Stool samples
  • Lumbar puncture—to test fluid around the brain and spinal cord
  • Cultures of abscesses, sores, soft tissues, wounds, or other areas

These tests are not always done. They may only be done for severe infections and those that do not get better.

Treatment

The goal is to clear the infection. If not treated, gram negative bacteria can lead to serious problems and death.

Bacterial infections are treated with antibiotics. However, common antibiotics may not work for this type of infection. Older antibiotics may work better. The doctor may need to try different ones.

Prevention

The risk of infection may be reduced by:

  • Good infection control in health care settings
  • Washing hands often
  • Not touching wounds or incisions—and keeping them clean and bandaged
RESOURCES:

Centers for Disease Control and Prevention
https://www.cdc.gov

IDSA—Infectious Diseases Society of America
http://www.idsociety.org

CANADIAN RESOURCES:

Infection Prevention and Control Canada
https://ipac-canada.org

Public Health Agency of Canada
https://www.canada.ca

REFERENCES:

Antibiotic resistance threats in the United States, 2013. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/drugresistance/pdf/ar-threats-2013-508.pdf. Accessed April 2, 2021.

Bacteremia with gram-negative bacilli. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/bacteremia-with-gram-negative-bacilli. Accessed April 2, 2021.

Bacterial meningitis in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/bacterial-meningitis-in-adults . Accessed April 2, 2021.

Carbapenem-resistant Enterobacteriaceae (CRE). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/carbapenem-resistant-enterobacteriaceae-cre . Accessed April 2, 2021.

Extended spectrum beta-lactamases (ESBLs). EBSCO DynaMed website. Available at: https://www.dynamed.com/drug-review/extended-spectrum-beta-lactamases-esbls . Accessed April 2, 2021.

Gram-negative bacteria. National Institute of Allergy and Infectious Diseases website. Available at: https://www.niaid.nih.gov/research/antimicrobial-resistance. Accessed April 2, 2021.

Gram-negative bacteria infections in healthcare settings. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/hai/organisms/gram-negative-bacteria.html. Accessed April 2, 2021.

MacVane SH. Antimicrobial resistance in the intensive care unit: a focus on gram-negative bacterial infections. J Intensive Care Med. 2017;32(1):25-37.

Last reviewed December 2020 by EBSCO Medical Review Board David L. Horn, MD, FACP  Last Updated: 4/2/2021