Septic arthritis caused by Kingella kingae.

Kingella kingae is a slow-growing, fastidious gram-negative coccobacillus that is a normal inhabitant of the oropharynx of man, but it has rarely been implicated as a human pathogen. Two cases of septic arthritis caused by this organism are reported along with a review of seven previously reported cases of infections caused by this organism. Bone and joint infections predominate. Gram's-stained smears of pus from bone or joint fluid aspirate have been negative for organisms, and a delay of growth in cultures with initial difficulty in classification of the isolate is characteristic. Kingella kingae organisms have been uniformly sensitive to the penicillins and all other commonly used antibiotics that were tested. Response to treatment was good in all nine patients found to have infections caused by this organism.