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
- Wound infections
- Sexually transmitted infections, such as gonorrhea
Development of Pneumonia in the Air Sacs of the Lungs
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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
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 depend on the site of the infection. Fever is a common sign.
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.
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.
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
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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