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)
Your notes
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.