Oropharyngeal K kingae may predict osteoarticular infection

A study in 123 children aged from 6 to 48 months with atraumatic osteoarticular symptoms confirmed investigators’ hypothesis that oropharyngeal carriage of Kingella kingae in children aged younger than 48 months with acute osteoarticular infection (AOI) is strong evidence that this microorganism is responsible.

Children with joint pain, a limp, or restricted limb movement and no history of trauma were included in the study. In addition to undergoing a clinical evaluation and radiologic investigations, all participants provided an oropharyngeal swab, synovial fluid, bone biopsy specimen, and peripheral blood samples investigators analyzed with a real-time polymerase chain reaction (PCR) assay specific to K kingae.

Forty patients received a diagnosis of AOI, as confirmed by microbiologic studies or magnetic resonance imaging. In 30 (75%) of these patients, K kingae was identified as the causative organism by PCR or culture of bone, joint, or blood specimen. All 30 patients also had oropharyngeal PCRs positive for K kingae. Investigators determined that sensitivity of the oropharyngeal swab PCR assay for K kingae was 100%, with specificity of 90.5% (Ceroni D, et al. Pediatrics. 2013;131[1]:e230-e235).

Commentary

With improved culture techniques and molecular diagnostic tools, the role of this pathogen in bone and joint infections is coming into focus. From 8% to 12% of young children have asymptomatic nasopharyngeal colonization with K kingae. It is thought that some colonized children develop bacteremia with the organism, allowing seeding of joints or bone in a few. Knowledge of the organism is important because K kingae osteoarticular infection may have a subtler, insidious onset than infection caused by Staphylococcus aureus, and ideal treatment differs; typically K kingae is resistant to clindamycin.