A colonization study was performed in response to the Minnesota outbreak. Published in Pediatrics in August 2005, the investigators demonstrated that 13% of children at the index day care center (and 45% in the room where the cluster occurred) were colonized in the nasopharynx with K. kingae. Interestingly, no day care center staff or children less than 16 months old were colonized. They compared the nasopharyngeal colonization results with a control day care center. Similarly, 16% of toddler age children were colonized. (Pediatrics 2005;116:e206–13).
In the pre-Hib vaccine era, we routinely used to use rifampin to eradicate Hib carriage among children in day care. Rifampin was used to attempt decolonization of children in the outbreak but proved to be only moderately effective: three of nine children who took rifampin remained positive on reculture 10–14 days later.
As practitioners recognize the importance of recognizing K. kingae as a pathogen in the infant with skeletal infection (and others are noting the emergence of clindamycin-resistant MRSA), clinical decision making in cases of pediatric skeletal infection are becoming increasingly difficult.
A collaborative approach with you, your infectious disease specialist, and orthopedic surgeon that focuses on early diagnosis, pathogen isolation, prompt surgical drainage, and appropriate antimicrobial therapy should allow for the best outcomes.
An example of a typical Gram stain of organisms from a Kingella kingae colony is shown. Courtesy Dr. Pablo Yagupsky