Kingella species

Paul Auwaerter, M.D.


  • Fastidious, Gram-negative facultative anaerobic coccobacillus of the Neisseriaceae family.
    • Labs may misidentify due to the organism’s tendency for crystal violet dye retention, therefore appearing Gram-positive.
    • β-hemolytic, catalase-negative; will not grow on MacConkey agar.
    • Polysaccharide capsule aids in virulence and invasive abilities.
      • Described factors: including type IV pili and the Knh trimeric autotransporter (adherence to the host), a potent RTX-family toxin (epithelial barrier breach), and multiple surface polysaccharides (complement and neutrophil resistance).
  • Part of normal oral/respiratory and GU flora, especially in children.
    • Colonization rates:
      • 0-6 mos: 1%
      • 12 mos- 4 yrs: 10-28% (toward higher-end, especially in the daycare population)
      • Adults: 1%
  • Kingella kingae most frequent human pathogen.
    • Other occasional species include K. dentrificans and K. oralis.
  • Generally susceptible to many antibiotic classes.

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Last updated: December 11, 2022