Summary about Disease
Kingella kingae* is a Gram-negative bacterium that commonly colonizes the upper respiratory tract of young children. While often asymptomatic, it can cause a range of invasive infections, primarily in children between 6 months and 4 years old. These infections most commonly include bone and joint infections, bacteremia (bacteria in the bloodstream), and, less frequently, endocarditis (infection of the heart valves).
Symptoms
Symptoms vary depending on the type of infection:
Skeletal infections (septic arthritis, osteomyelitis): Pain, swelling, redness, warmth, and limited range of motion in the affected joint or bone. Fever may or may not be present.
Bacteremia: Fever, irritability, lethargy, poor feeding.
Endocarditis: Fever, fatigue, shortness of breath, heart murmur (may be new or changed).
Respiratory infections: Symptoms of upper respiratory infection, such as runny nose, sore throat, and cough, may precede or accompany invasive infections.
Causes
Kingella kingae* infection is caused by the bacterium *Kingella kingae*.
The bacteria colonize the upper respiratory tract (nose and throat), particularly in young children.
Invasive infections occur when the bacteria enter the bloodstream and spread to other parts of the body.
Minor trauma, viral respiratory infections, and pre-existing bone or joint conditions may increase the risk of invasive disease.
Medicine Used
4. Medicine used
Antibiotics are the primary treatment for Kingella kingae infections.
Commonly used antibiotics include:
Beta-lactam antibiotics: Cephalosporins (e.g., cefuroxime, ceftriaxone, cefazolin) are often the first-line treatment.
Other antibiotics: Macrolides (e.g., azithromycin), clindamycin, and fluoroquinolones (in older patients, if appropriate).
The specific antibiotic and duration of treatment depend on the type and severity of the infection. Prolonged antibiotic therapy (several weeks) is often necessary for bone and joint infections or endocarditis.
Is Communicable
Yes, Kingella kingae* can be spread from person to person, primarily through respiratory droplets (coughing, sneezing) or direct contact with respiratory secretions.
However, colonization with K. kingae is common in young children, and invasive disease is relatively rare, suggesting that transmission does not always lead to infection.
Precautions
Good hygiene: Frequent handwashing with soap and water, especially after coughing or sneezing.
Respiratory etiquette: Covering the mouth and nose when coughing or sneezing.
Avoid sharing utensils and drinks: Especially with young children.
Prompt medical attention: Seek medical evaluation for children with fever, joint pain, or other signs of possible infection.
How long does an outbreak last?
Outbreaks of Kingella kingae* infections in childcare settings or communities are uncommon.
The duration of an outbreak, if one occurs, would depend on factors such as the effectiveness of control measures (e.g., hygiene practices, early diagnosis and treatment), the number of individuals colonized, and the susceptibility of the population. There is limited data for the length of an outbreak.
How is it diagnosed?
Blood culture: To detect bacteremia.
Synovial fluid culture: If septic arthritis is suspected, fluid from the affected joint is aspirated and cultured.
Bone biopsy or aspirate culture: If osteomyelitis is suspected.
Echocardiogram: If endocarditis is suspected, to visualize the heart valves.
PCR (polymerase chain reaction): PCR testing of synovial fluid, bone, or blood samples can rapidly detect K. kingae DNA. This is increasingly used and can be more sensitive than culture.
Respiratory Sample PCR: PCR analysis from the nasopharynx is not recommended to diagnose invasive infections.
Timeline of Symptoms
The incubation period (time between exposure and onset of symptoms) for Kingella kingae* infections is typically short, often a few days to a week.
Symptoms may develop rapidly, especially in cases of septic arthritis or bacteremia.
In some cases, a preceding upper respiratory infection may occur several days before the onset of invasive symptoms.
The timeline can vary depending on the type of infection and the individual's immune response.
Important Considerations
Kingella kingae* infections are most common in young children (6 months to 4 years old).
Early diagnosis and treatment are crucial to prevent serious complications, such as permanent joint damage or endocarditis.
Clinicians should consider K. kingae as a possible cause of bone and joint infections, even in the absence of fever or elevated inflammatory markers.
PCR testing has improved the diagnosis of K. kingae infections, especially in cases where cultures are negative.
While Kingella kingae is generally susceptible to a variety of antibiotics, antibiotic resistance can occur, so susceptibility testing should be performed when possible.