Kingella Kingae Osteoarticular Infections in Young Children: Clinical Features and Contribution of a New Specific Real-time PCR Assay to the Diagnosis

Background Kingella kingae is a known cause of osteoarticular infections in children younger than 4 years of age, but it is not always recoverable in culture. Molecular methods are increasingly used for diagnosis. Methods To facilitate diagnosis of K. kingae septic arthritis, we developed a real-time polymerase chain reaction (PCR) assay for the detection of K. kingae that targets the repeat-in-toxin gene (rtxB). Results We present three pediatric patients with K. kingae septic arthritis at our institution who were diagnosed using the real-time PCR assay. All underwent arthrotomy with irrigation and debridement and were symptom-free after 3 weeks of therapy with β-lactam antibiotics. Cultures of synovial fluid or tissue grew K. kingae in two of three; K. kingae real-time PCR was positive in all three patients. In addition, 11 cases of K. kingae osteoarticular infection were diagnosed through Mayo Medical Laboratories using this assay. The limit of detection of the real-time PCR assay was 73.7 colony-forming unit (CFU)/µL for tissue and 1.3 CFU/µL for synovial fluid. Conclusions PCR-based detection methods are faster and more sensitive than conventional culture-based methods for the diagnosis of K. kingae osteoarticular infections in children.

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Specific Real-Time Polymerase Chain Reaction Places Kingella kingae as the Most Common Cause of Osteoarticular Infections in Young Children

The Pediatric Infectious Disease Journal ◽

10.1097/01.inf.0000259954.88139.f4 ◽

2007 ◽

Vol 26 (5) ◽

pp. 377-381 ◽

Cited By ~ 176

Author(s):

Sylvia Chometon ◽

Yvonne Benito ◽

Mourad Chaker ◽

Sandrine Boisset ◽

Christine Ploton ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Young Children ◽

Real Time ◽

Chain Reaction ◽

Kingella Kingae ◽

Common Cause ◽

Osteoarticular Infections ◽

Polymerase Chain

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Molecular diagnosis of Kingella kingae osteoarticular infections by specific real-time PCR assay

Journal of Medical Microbiology ◽

10.1099/jmm.0.47707-0 ◽

2009 ◽

Vol 58 (1) ◽

pp. 65-68 ◽

Cited By ~ 56

Author(s):

Abdessalam Cherkaoui ◽

Dimitri Ceroni ◽

Stéphane Emonet ◽

Yan Lefevre ◽

Jacques Schrenzel

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Cell Types ◽

Cross Reactivity ◽

Toxin Gene ◽

Rrna Gene ◽

Putative Virulence Factor ◽

Pcr Assay ◽

Kingella Kingae ◽

Rtx Toxin

Kingella kingae is an emerging pathogen that is recognized as a causative agent of septic arthritis and osteomyelitis, primarily in infants and children. The bacterium is best detected by rapid inoculation in blood culture systems or by real-time PCR assays. Pathogenesis of the agent was linked recently to the production of a potent cytotoxin, known as RTX, which is toxic to a variety of human cell types. The locus encoding the RTX toxin is thought to be a putative virulence factor, and is, apparently, essential for inducing cytotoxic effects on respiratory epithelial, synovial and macrophage-like cells. Herein, we describe a novel real-time PCR assay that targets the RTX toxin gene and illustrate its use in two clinical cases. The assay exhibited a sensitivity of 30 c.f.u., which is 10-fold more sensitive than a previously published semi-nested broad-range 16S rRNA gene PCR, and showed no cross-reactivity with several related species and common osteoarticular pathogens.

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