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El Houmami N, Durand GA, Bzdrenga J, Darmon A, Minodier P, Seligmann H, Raoult D, Fournier PE. A New Highly Sensitive and Specific Real-Time PCR Assay Targeting the Malate Dehydrogenase Gene of Kingella kingae and Application to 201 Pediatric Clinical Specimens. J Clin Microbiol 2018; 56:e00505-18. [PMID: 29875189 PMCID: PMC6062779 DOI: 10.1128/jcm.00505-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022] Open
Abstract
Kingella kingae is a significant pediatric pathogen responsible for bone and joint infections, occult bacteremia, and endocarditis in early childhood. Past efforts to detect this bacterium using culture and broad-range 16S rRNA gene PCR assays from clinical specimens have proven unsatisfactory; therefore, by the late 2000s, these were gradually phased out to explore the benefits of specific real-time PCR tests targeting the groEL gene and the RTX locus of K. kingae However, recent studies showed that real-time PCR (RT-PCR) assays targeting the Kingella sp. RTX locus that are currently available for the diagnosis of K. kingae infection lack specificity because they could not distinguish between K. kingae and the recently described Kingella negevensis species. Furthermore, in silico analysis of the groEL gene from a large collection of 45 K. kingae strains showed that primers and probes from K. kingaegroEL-based RT-PCR assays display a few mismatches with K. kingae groEL variations that may result in decreased detection sensitivity, especially in paucibacillary clinical specimens. In order to provide an alternative to groEL- and RTX-targeting RT-PCR assays that may suffer from suboptimal specificity and sensitivity, a K. kingae-specific RT-PCR assay targeting the malate dehydrogenase (mdh) gene was developed for predicting no mismatch between primers and probe and 18 variants of the K. kingae mdh gene from 20 distinct sequence types of K. kingae This novel K. kingae-specific RT-PCR assay demonstrated high specificity and sensitivity and was successfully used to diagnose K. kingae infections and carriage in 104 clinical specimens from children between 7 months and 7 years old.
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Affiliation(s)
- Nawal El Houmami
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Guillaume André Durand
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Janek Bzdrenga
- Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Anne Darmon
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Philippe Minodier
- Department of Pediatric Emergency Medicine, North Hospital, Marseille, France
| | - Hervé Seligmann
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Didier Raoult
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Pierre-Edouard Fournier
- UMR VITROME, Aix-Marseille Université, IRD, Service de Santé des Armées, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
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Genome Analysis of Kingella kingae Strain KWG1 Reveals How a β-Lactamase Gene Inserted in the Chromosome of This Species. Antimicrob Agents Chemother 2015; 60:703-8. [PMID: 26574009 DOI: 10.1128/aac.02192-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/08/2015] [Indexed: 11/20/2022] Open
Abstract
We describe the genome of a penicillinase-producing Kingella kingae strain (KWG1), the first to be isolated in continental Europe, whose bla(TEM-1) gene was, for the first time in this species, found to be chromosomally inserted. The bla(TEM) gene is located in an integrative and conjugative element (ICE) inserted in Met-tRNA and comprising genes that encode resistance to sulfonamides, streptomycin, and tetracycline. This ICE is homologous to resistance-conferring plasmids of K. kingae and other Gram-negative bacteria.
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