Bacterial infection

Medical Specialties: Emergency medicine, Family practice, Pediatrics

Clinical Definition

A bacterial infection is an illness due to pathogenic bacteria that gain entrance to the body through various means, including the digestive system, the respiratory system and the skin. Once inside the body, the bacteria reproduce, which may lead to various symptoms and illnesses. Bacterial infections are often treated with antibiotics.

In Our Own Words

A bacterial infection is an illness caused by bacteria. Bacteria are single-celled organisms. Most types of bacteria do not cause harm to humans, but about 1 percent can lead to illness and make someone sick. Bacteria get into the body in different ways. In some cases, it gets in through a break in the skin or through the nose. Bacteria can also enter the body through eating contaminated food.


Once inside the body, the bacteria multiply, and some give off specific toxins, which can add to the illness. As opposed to viral infections, bacterial infections are usually treated with antibiotics.

Common Types
  • Streptococcus
  • Staphylococcus
  • E. coli
Side Effects
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  • University of Colorado Hospital. “Care and Treatment for Bacterial Infections.” Accessed February 2014.
  • University of Rochester Medical Center. “Is it a Virus or Bacterium? Know the Difference.” Accessed February 2014.
  • Tortora G., Derrick B. “Principals of Anatomy and Physiology.” Wiley 2011. Accessed February 2014.
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