DIAGNOSING Kingella kingae OSTEOARTICULAR INFECTIONS IN YOUNG
CHILDREN VIA SPECIFIC OROPHARAYNGEAL SWAB PCR
R. ANDERSON1, V. DUBOIS-FERRIÈRE1, A. CHERKAOUI2, S MANZANO3, J. SCHRENZEL2, D. CERONI1
1SERVICE OF PEDIATRIC ORTHOPEDICS, 2SERVICE OF INFECTIOUS DISEASES, 3 EMERGENCY ROOM, UNIVERSITY HOSPITAL OF GENEVA, SWITZERLAND
Major cause of osteoarticular infections (OAI) in children under 4 years.
Belongs to the normal oropharyngeal flora (8-9% asymptomatic carriers)
Colonization of the oropharynx is a prerequisite for invasive infections which is mediated by the production of a potent RTX cytotoxin.
However diagnosing OAI caused by K. kingae remain challenging (mild clinical, biological and radiological signs and difficult germ cultivation).
Background
Kingella kingae:
Background
Study Aim To investigate whether a specific oropharyngeal swab real time
PCR (oropharyngeal K. kingae PCR) could improve the recognition of K. kingae OAI in young children.
Specific real time PCR targeting the RTX toxin coding DNA of K. kingae
Prospective cohort study of all young children presenting with atraumatic osteoarticular complaints between 2008 and 2011 to our emergency room.
Methods
EnrolmentClinical evaluation
1st phase investigations 2nd phase
diagnostic investigations
• Atraumatic OA complaints
• Age 6-48 months
• Clinical evaluation • CBC, CRP, VS, blood culture • Oropharyngeal K. kingae PCR
• MRI • Infection site puncture• Culture, broad range PCR• K. kingae PCR on osteo-
articular aspirate
Findings suggestive for OAI
Results
K. kingae OAI
30 cases
OAI (other)
1 case
no OAI
83 cases
H. Influenzae
123 patients enrolled
30 orophary. K. kingae PCR +
MRI consistent with OAI despite negative
microbiology
suspected OAI
9 cases
8 orophary. K. kingae PCR +
76 orophary. K. kingae PCR -
9 orophary. K. kingae PCR +
Excluded from statistical analysis
Results
Diagnostic performances of the oropharyngeal swab K. kingae specific PCR test (95% CI)
Sensitivity 100% (88.4; 100)
Specificity 90.5% (82.1; 95.8)
Positive predictive value 78.9% (62.7; 90.4)
Negative predictive value 100% (95.5; 100)
K. kingae is the 1st microorganism responsible for OAI in children under 4 years (>95% in this study)
Detection of K. kingae DNA in oropharyngeal swabs of children with clinical findings of OAI is predictive for K kingae OAI and negative result excludes OAI caused by this bacteria.
A valuable non invasive diagnostic tool which may improve the recognition of K. kingae OAI among young children.
Conclusions
Implementation of oropharyngeal K.kingae PCR as diagnostic tool for OAI in our setting:
Changed our diagnostic approach
Faster recognition of OAI in young children
Improved therapeutic management
Increased recognition of OAI due to K. kingae
Clinical perspecti ves
Thank you for your
attention