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J Pediatr Infect Dis 2018; 13(03): 216-223
DOI: 10.1055/s-0038-1641603
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Real-Time PCR Assay for Detection of Kingella kingae in Children

Theresa Madigan
1   Division of Pediatric Infectious Diseases, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, United States
,
Scott A. Cunningham
2   Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States
,
Poornima Ramanan
2   Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States
,
Micah M. Bhatti
3   Clinical Microbiology Laboratory, Department of Laboratory Medicine, The University of Texas, MD Anderson Cancer Center, Houston, Texas, United States
,
Robin Patel
2   Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States
4   Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States
› Author Affiliations
Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Further Information

Publication History

03 January 2018

02 March 2018

Publication Date:
11 April 2018 (online)

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Abstract

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.

Keywords

Kingella kingae - real-time PCR - children

Note

This research was presented in part at the St. Jude Pediartic Infectious Diseases (PIDS) Research Conference held at Memphis, TN, March 2018.