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Journal of Clinical Microbiology, August 2009, p. 2489-2495, Vol. 47, No. 8
0095-1137/09/$08.00+0 doi:10.1128/JCM.00290-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Specific Distribution within the Enterobacter cloacae Complex of Strains Isolated from Infected Orthopedic Implants
Philippe C. Morand,1,2,3*
Annick Billoet,2
Martin Rottman,4,5
Valérie Sivadon-Tardy,5,6
Luc Eyrolle,7
Luc Jeanne,7
Asmaa Tazi,1,2,3
Philippe Anract,1,8
Jean-Pierre Courpied,1,8
Claire Poyart,1,2,3 and
Valérie Dumaine8
Faculty of Medicine, Université Paris Descartes, Paris, France,1 Department of Bacteriology, Cochin Hospital (AP-HP), Paris, France,2 Institut Cochin, INSERM U567, Paris, France,3 Laboratoire de Microbiologie, Hôpital Raymond Poincaré (AP-HP), Garches, France,4 EA 3647, Faculté de Médecine Paris-Ile de France-Ouest, Université de Versailles-Saint-Quentin en Yvelines, Garches, France,5 Department of Microbiology, Ambroise Paré Hospital (AP-HP), Boulogne-Billancourt, France,6 Department of Anesthesiology, Cochin Hospital (AP-HP), Paris, France,7 Department of Orthopedic Surgery, Cochin Hospital (AP-HP), Paris, France8
Received 9 February 2009/ Returned for modification 14 April 2009/ Accepted 4 June 2009
Bacteria belonging to the Enterobacter genus are frequently isolated from clinical samples but are unusual causative agents of orthopedic implant infections. Twelve genetic clusters (clusters I to XII) and one sequence crowd (sequence crowd xiii) can be distinguished within the Enterobacter cloacae nomenspecies on the basis of hsp60 sequence analysis, and until now, none of these clusters could be specifically associated with a disease. In order to investigate if specific genetic clusters would be involved in infections of orthopedic material, two series of bacterial clinical isolates identified as E. cloacae by routine phenotypic identification methods were collected either from infected orthopedic implants (n = 21) or from randomly selected samples of diverse anatomical origins (control; n = 52). Analysis of the hsp60 gene showed that genetic clusters III, VI, and VIII were the most frequent genetic clusters detected in the control group, whereas cluster III was poorly represented among the orthopedic implant isolates (P = 0.006). On the other hand, E. hormaechei (clusters VI and VIII), but not cluster III, is predominantly associated with infections of orthopedic implants and, more specifically, with infected material in the hip (P = 0.019). These results support the hypothesis that, among the isolates within the E. cloacae complex, E. hormaechei and hsp60 gene sequencing-based cluster III are involved in pathogenesis in different ways and highlight the need for more accurate routine Enterobacter identification methods.
* Corresponding author. Mailing address: Service de Bactériologie, Hôpital Cochin AP-HP, Université Paris Descartes, 27 rue du Faubourg Saint-Jacques, 75014 Paris, France. Phone: 33 (0)1 58 41 27 91. Fax: 33 (0)1 58 41 15 48. E-mail: philippe.morand{at}cch.aphp.fr
Published ahead of print on 10 June 2009.
Journal of Clinical Microbiology, August 2009, p. 2489-2495, Vol. 47, No. 8
0095-1137/09/$08.00+0 doi:10.1128/JCM.00290-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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