Kingella Kingae Infection

Kingella kingae or K. kingae is a bacteria that can cause infection. Most of the time, these bacteria do not cause infection. They live in the back of most young children's throats. However, an infection can set in if the bacteria get into the blood. Joints, bones, and the heart can become infected.

Most children who get this type of infection are 6 months to 2 years old. They are usually otherwise healthy. K. kingae infections can be treated. Most children recover completely.


It is thought that children pick up the bacteria from close contact with other children. This can happen at daycare or wherever children play together. Infection sets in when K. kingae bacteria get into a child's bloodstream. How or why this occurs in some young children is not understood.


Signs of a K. kingae infection may include:

  • Fever.

  • Joint pain and swelling. This occurs most often in the knee or ankle.

  • Bone pain.

  • Limping.

  • Cough.

  • Chest pain.

  • Trouble breathing.


To decide if your child has a K. kingae infection, your caregiver may:

  • Take a sample of fluids from the child's body. This could be blood or fluid from a joint. Your caregiver will use the fluid to grow a culture of the bacteria in a lab.

  • Order blood tests. These tests can:

  • Check the number of white blood cells. A high number can be a sign of infection.

  • Check for a protein that changes during infection. It is called C-reactive protein (CRP).

  • Check the erythrocyte sedimentation rate (ESR). That is how fast red blood cells fall to the bottom of a test tube. The test can show if there is inflammation in the child's body. This is a sign of infection.

  • Take a magnetic resonance imaging scan (MRI). This test can show infection in bones or joints.

  • Do an echocardiography test. This test uses sound waves to take pictures of the inside of the heart.

  • Do a polymerase chain reaction (PCR) test. This test can find K. kingae by looking for its genetic makeup or DNA.


Antibiotic medicines usually work very well to treat a K. kingae infection. Penicillin and cephalosporin are antibiotics that are often used. At first, the medicine may be given through an intravenous line (IV). A needle is put in the child's arm or hand. The medicine flows into the child's body through the IV. Once the infection starts to clear up, your child may be given antibiotics in pill form. Antibiotics may be needed for as long as 6 weeks. This will depend on how bad the infection is and which part of the body is infected.


  • Give antibiotics as directed. Make sure your child finishes them even if he or she starts to feel better.

  • Only give over-the-counter or prescription medicines as directed by your caregiver.

  • Make sure your child drinks enough fluids to keep his or her urine clear or pale yellow.

  • Do not let your child go back to normal activities until your caregiver says it is okay.

  • Keep all follow-up appointments as directed. This is how your caregiver can make sure your child's treatment is working.


  • Your child has trouble taking his or her medicine.

  • Your child has an oral temperature above 102° F (38.9° C).

  • Your baby is older than 3 months with a rectal temperature of 100.5° F (38.1° C) or higher for more than 1 day.


  • Your child has worsening bone or joint pain.

  • Your child has trouble breathing.

  • Your child has an oral temperature above 102° F (38.9° C), not controlled by medicine.

  • Your baby is older than 3 months with a rectal temperature of 102° F (38.9° C) or higher.

  • Your baby is 3 months old or younger with a rectal temperature of 100.4° F (38° C) or higher.


  • Understand these instructions.

  • Will watch your child's condition.

  • Will get help right away if your child is not doing well or gets worse.