Bacterium
Kingella kingae
Fastidious HACEK coccobacillus of young children
KING-ell-uh KING-eye
High-yield clue
Leading cause of septic arthritis and osteomyelitis in children roughly 6-36 months old, often with only mild inflammatory signs.
Overview
A fastidious Gram-negative coccobacillus that colonizes the oropharynx and is a leading cause of osteoarticular infection in young children. It is a member of the HACEK group linked to culture-negative endocarditis.
Classification
- Gram-negative
- Coccobacillus
- HACEK group
- Facultative anaerobe
- Beta-hemolytic on blood agar
Lab & identification clues
- Recovery improved by inoculating aspirates into blood-culture bottles
- NAAT/PCR of joint fluid concept
- Fastidious, capnophilic growth vocabulary
- Oxidase positive
Associations
- Oropharyngeal colonization in toddlers
- Daycare cluster/outbreak epidemiology
- Osteoarticular infection study association
- HACEK culture-negative endocarditis framing
Commonly confused with
- Haemophilus influenzae
- Staphylococcus aureus (other cause of pediatric joint infection)
Frequently asked questions
What is Kingella kingae?
A fastidious Gram-negative coccobacillus that colonizes the oropharynx and is a leading cause of osteoarticular infection in young children. It is a member of the HACEK group linked to culture-negative endocarditis.
What is the Gram stain of Kingella kingae?
Kingella kingae is Gram negative.
What are the lab clues for Kingella kingae?
Lab clues for Kingella kingae include Recovery improved by inoculating aspirates into blood-culture bottles; NAAT/PCR of joint fluid concept; Fastidious, capnophilic growth vocabulary; Oxidase positive.
What is Kingella kingae commonly confused with?
Kingella kingae is commonly confused with Haemophilus influenzae and Staphylococcus aureus (other cause of pediatric joint infection).
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.