Clinical features of septic arthritis with and without Kingella kingae Detection by real-time PCR

Abstract

Aim: To evaluate the clinical features of Kingella kingae osteoarticular infections. Method: We performed a retrospective audit of all children from whom we received a specimen for K. kingae real-time PCR (targeting rtxA and cpn60), as well as children with positive culture results from joint specimens, between May 2019 and April 2021. Microscopy and culture was performed according to standard protocols. Results: Fifty-six children with features of osteoarticular infection subsequently confirmed by imaging, were included. The median age of children with K. kingae detected, compared to other pathogens, was 19 months versus 9 years. 53% versus 17% had recent respiratory infection. Median CRP was 32 versus 62 mg/L. Organisms were seen on fluid microscopy in 0% versus 67% of patients. 0% versus 28% grew the pathogen from blood cultures. Cefazolin was chosen for inpatient directed therapy in 82% versus 16% of cases. K. kingae was cultured from joint aspirates in only 2 cases. Discussion: Patients with K. kingae septic arthritis have distinct clinical features, and molecular tests are important to confirm the diagnosis and direct targeted therapy. Molecular tests appear much more sensitive than routine culture for detection of K. kingae infection.1 1.Ilharreborde B, Bidet P, Lorrot M, et al. New real-time PCR-based method for Kingella kingae DNA detection: application to samples collected from 89 children with acute arthritis. J Clin Microbiol 2009; 47: 1837–41.