Osteomyelitis/septic arthritis caused by Kingella kingae among day care attendees--Minnesota, 2003

Kingella kingae is a fastidious gram-negative coccobacillus that colonizes the respiratory and oropharyngeal tract in children. K. kingae occasionally causes invasive disease, primarily osteomyelitis/septic arthritis in young children, bacteremia in infants, and endocarditis in school-aged children and adults. Although diagnosis of this organism frequently is missed, invasive disease is uncommon. Only sporadic, non-epidemiologically linked cases have been reported previously. In October 2003, the Minnesota Department of Health (MDH) investigated a cluster of two confirmed cases and one probable case of osteomyelitis/septic arthritis caused by K. kingae among children aged 17-21 months attending the same toddler classroom in a day care center. All reported within the same week with onset of fever, preceding or concurrent upper respiratory illness (URI), and refusal to bear weight on the affected limb. This report summarizes these cases and describes the epidemiologic investigation of the day care center. The findings underscore the need for clinicians and laboratorians to consider K. kingae infection in young children with Gram stain--negative or culture-negative skeletal infections.