Kingella kingae infections in children.

Kingella kingae is a beta-hemolytic gram-negative bacillus. It was first described in the 1960's by EO King and has been reported as a cause of osteo-articular pediatric infections since the early 1980's. We performed a retrospective review of all pediatric cases of invasive K. kingae infection between 1997 and 2002, in order to define the incidence, clinical presentation and outcome of invasive K. kingae infections in a pediatric population. During the study period, a total of 24 pediatric patients with K. kingae infection were identified. There were 15 blood culture isolates of K. kingae, out of a total of 1151 (1.3%) positive blood cultures, and 9 synovial fluid culture isolates out of a total of 76 (11.8%) positive synovial fluids. Fifteen patients had osteo-articular infections and 9 had primary bacteremia without osteo-articular infection. Outcome was favorable in all cases and only in 2 patients with knee joint infection was surgical intervention performed, by means of formal knee arthrotomy. All patients recovered uneventfully, in 7 cases without any intervention and in the others with intravenous or oral antibiotic. In conclusion, invasive K. kingae infection is not uncommon in Israel. It usually has a mild course and thus is not always detected and treated. As K. kingae grows best in blood culture broth, blood and joint fluid should always be inoculated into blood culture bottles in suspected cases. This bacterium is highly sensitive to betalactame antibiotics and infection resolves quickly with antibiotic treatment. Surgical intervention for osteo-articular infection is seldom indicated.