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Infection and Immunity, June 2009, p. 2272-2284, Vol. 77, No. 6
0019-9567/09/$08.00+0 doi:10.1128/IAI.01333-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
The Plasmid of Escherichia coli Strain S88 (O45:K1:H7) That Causes Neonatal Meningitis Is Closely Related to Avian Pathogenic E. coli Plasmids and Is Associated with High-Level Bacteremia in a Neonatal Rat Meningitis Model
Chantal Peigne,1
Philippe Bidet,1
Farah Mahjoub-Messai,1
Céline Plainvert,1
Valérie Barbe,2
Claudine Médigue,3
Eric Frapy,4
Xavier Nassif,4
Erick Denamur,5
Edouard Bingen,1 and
Stéphane Bonacorsi1*
Laboratoire d'Études de Génétique Bactérienne dans les Infections de l'Enfant (EA 3105), Université Paris Diderot, Hôpital Robert Debré, 75019 Paris,1 Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Génomique, Génoscope, 91057 Evry Cedex,2 Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Génomique, Atelier de Génomique Comparative, CNRS UMR8030, 91057 Evry Cedex,3 Institut National de la Santé et de la Recherche Médicale U570 and Université Paris Descartes, 75015 Paris,4 Institut National de la Santé et de la Recherche Médicale U722, 75018 Paris, and Université Paris Diderot, Site Xavier Bichat, 75018 Paris, France5
Received 31 October 2008/ Returned for modification 12 January 2009/ Accepted 15 March 2009
A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B21 was recently identified in France, where it accounts for one-third of E. coli neonatal meningitis cases. Here we describe the sequence, epidemiology and function of the large plasmid harbored by strain S88, which is representative of the O45:K1 clonal group. Plasmid pS88 is 133,853 bp long and contains 144 protein-coding genes. It harbors three different iron uptake systems (aerobactin, salmochelin, and the sitABCD genes) and other putative virulence genes (iss, etsABC, ompTP, and hlyF). The pS88 sequence is composed of several gene blocks homologous to avian pathogenic E. coli plasmids pAPEC-O2-ColV and pAPEC-O1-ColBM. PCR amplification of 11 open reading frames scattered throughout the plasmid was used to investigate the distribution of pS88 and showed that a pS88-like plasmid is present in other meningitis clonal groups such as O18:K1, O1:K1, and O83:K1. A pS88-like plasmid was also found in avian pathogenic strains and human urosepsis strains belonging to subgroup B21. A variant of S88 cured of its plasmid displayed a marked loss of virulence relative to the wild-type strain in a neonatal rat model, with bacteremia more than 2 log CFU/ml lower. The salmochelin siderophore, a known meningovirulence factor, could not alone explain the plasmid's contribution to virulence, as a salmochelin mutant displayed only a minor fall in bacteremia (0.9 log CFU/ml). Thus, pS88 is a major virulence determinant related to avian pathogenic plasmids that has spread not only through meningitis clonal groups but also human urosepsis and avian pathogenic strains.
* Corresponding author. Mailing address: Service de Microbiologie, Hôpital Robert-Debré, 48 blvd. Sérurier, 75395 Paris cedex 19, France. Phone: 33 1 40 03 23 40. Fax: 33 1 40 03 24 50. E-mail: stephane.bonacorsi{at}rdb.aphp.fr
Published ahead of print on 23 March 2009.
Infection and Immunity, June 2009, p. 2272-2284, Vol. 77, No. 6
0019-9567/09/$08.00+0 doi:10.1128/IAI.01333-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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