EBM Review: Detection of Kingella kingae osteoarticular infections in children by oropharyngeal swab PCR.

Ceroni D, Dubois-Ferriere V, Cherkaoui A, Gesuele R, Combescure C, Lamah L, Manzano S, Hibbs J, Schrenzel J. Detection of Kingella kingae osteoarticular infections in children by oropharyngeal swab PCR. Pediatrics. 2013 Jan;131(1):e230-5.

Full-text for Children’s and Emory users.

OBJECTIVE: The purpose of this study was to investigate if oropharyngeal swab polymerase chain reaction (PCR) could predict osteoarticular infection (OAI) due to Kingella kingae in young children. 

METHODS: One hundred twenty-three consecutive children aged 6 to 48 months presenting with atraumatic osteoarticular complaints were prospectively studied. All had a clinical evaluation, imaging, and blood samples. Blood and oropharyngeal specimens were tested with a PCR assay specific for K kingae. OAI was defined as bone, joint, or blood detection of pathogenic bacteria, or MRI consistent with infection in the absence of positive microbiology. K kingae OAI was defined by blood, bone, or synovial fluid positivity for the organism by culture or PCR.

RESULTS: Forty children met the OAI case definition; 30 had K kingae OAI, 1 had another organism, and 9 had no microbiologic diagnosis. All 30 oropharyngeal swabs from the K kingae case patients and 8 swabs from the 84 patients without OAI or with OAI caused by another organism were positive. The sensitivity and specificity of the oropharyngeal swab PCR assay for K kingae were 100% and 90.5%, respectively.

CONCLUSIONS: Detection of K kingae DNA in oropharyngeal swabs of children with clinical findings of OAI is predictive of K kingae OAI. If these findings are replicated in other settings, detection of K kingae by oropharyngeal swab PCR could improve the recognition of OAI.

Reviewed by Kristina Betters, MD and Amelia Thompson, MD

Main Points:

  • Kingella kingae is a leading cause of osteoarticular infections in children less than 48 months of age
  • Kingella kingae is very difficult to isolate in cultures- often causative organism in culture negative osteoarticular infections; often PCR of joint fluid/aspirate needed to ascertain diagnosis
  • Investigators attempting to use oral pharyngeal PCR as non-invasive diagnostic test for diagnosing K. kingae osteoarticular infections
  • All subjects tested presented with concern for osteoarticular infection (no healthy controls in study)
  • In study population very high rate of K. kingae infection (and low staph infection rate). May not be applicable to our treatment population in Atlanta.
  • Oral pharyngeal PCR had high sensitivity/specificity, but somewhat low sample size and lower positive predictive value and negative predictive value
  • Potential future directions: determining asymptomatic oral carriage rate of K. kingae, increasing sample size, expanding to multi-center trial for more heterogeneous sample

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