Polymerase chain reaction detection of Kingella kingae in children with culture-negative septic arthritis in eastern Ontario.
BACKGROUND
The bacterium Kingella kingae may be an under-recognized cause of septic arthritis in Canadian children because it is difficult to grow in culture and best detected using molecular methods.


OBJECTIVE
To determine whether K kingae is present in culture-negative joint fluid specimens from children in eastern Ontario using polymerase chain reaction (PCR) detection methods.


METHODS
K kingae PCR testing was performed using residual bacterial culture-negative joint fluid collected from 2010 to 2013 at a children's hospital in Ottawa, Ontario. The clinical features of children with infections caused by K kingae were compared with those of children with infections caused by the 'typical' septic arthritis bacteria, Staphylococcus aureus and Streptococcus pyogenes.


RESULTS
A total of 50 joint fluid specimens were submitted over the study period. Ten were culture-positive, eight for S aureus and two for S pyogenes. Residual joint fluid was available for 27 of the 40 culture-negative specimens and K kingae was detected using PCR in seven (25.93%) of these samples. Children with K kingae were significantly younger (median age 1.7 versus 11.3 years; P=0.01) and had lower C-reactive protein levels (median 23.8 mg/L versus 117.6. mg/L; P=0.01) than those infected with other bacteria.


CONCLUSIONS
K kingae was frequently detected using PCR in culture-negative joint fluid specimens from children in eastern Ontario. K kingae PCR testing of culture-negative joint samples in children appears to be warranted.
Department of Laboratory Medicine and Pathology, University of Ottawa, Ottawa, Ontario; Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario.
Robert
R
Slinger
Department of Laboratory Medicine and Pathology, University of Ottawa, Ottawa, Ontario.
Ioana
I
Moldovan
Department of Laboratory Medicine and Pathology, University of Ottawa, Ottawa, Ontario.
Jennifer
J
Bowes
Department of Laboratory Medicine and Pathology, University of Ottawa, Ottawa, Ontario; Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario.
Francis
F
Chan
Kingella kingae; PCR; Septic arthritis