Question 28.2

A 48-year-old patient with a history of mechanical aortic valve replacement presents with fever, fatigue, arthralgia and a tender abdomen. Trans-oesophageal echocardiography (TOE) is positive for prosthetic valve endocarditis. Blood cultures eventually grew Kingella kingae.

a)    Outline the antimicrobial treatment you would prescribe.    (5% marks)

b)    List the other fastidious gram negative organisms which can be associated with culture negative endocarditis.    (15% marks)

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College answer

Not available.


a) Ceftriaxone is the best, though many Kingella infections will apparently also respond to penicillins 

c) Kingella is the "K" in "HACEK", the acronym for the group of organisms that grow so slowly that the blood cultures will appear negative. The full group is:

  • Haemophilus species: H.aphrophilus, H.parainfluenzae and H.paraphrophilus
  • Actinobacillus and Aggregatobacter species
  • Cardiobacterium hominis
  • Eikenella corrodens
  • Kingella kingae


Adachi & Richardson. "Infective endocarditis caused by Kingella kingae." Canadian Medical Association Journal 128.9 (1983): 1087.

Sharara, Sima L., et al. "HACEK endocarditis: a review." Expert review of anti-infective therapy 14.6 (2016): 539-545.