title: Genomic Insights into a New Citrobacter koseri Strain Revealed Gene Exchanges with the Virulence-Associated Yersinia pestis pPCP1 Plasmid.
abstract: The history of infectious diseases raised the plague as one of the most devastating for human beings. Far too often considered an ancient disease, the frequent resurgence of the plague has led to consider it as a reemerging disease in Madagascar, Algeria, Libya, and Congo. The genetic factors associated with the pathogenicity of Yersinia pestis, the causative agent of the plague, involve the acquisition of the pPCP1 plasmid that promotes host invasion through the expression of the virulence factor Pla. The surveillance of plague foci after the 2003 outbreak in Algeria resulted in a positive detection of the specific pla gene of Y. pestis in rodents. However, the phenotypic characterization of the isolate identified a Citrobacter koseri. The comparative genomics of our sequenced C. koseri URMITE genome revealed a mosaic gene structure resulting from the lifestyle of our isolate and provided evidence for gene exchanges with different enteric bacteria. The most striking was the acquisition of a continuous 2 kb genomic fragment containing the virulence factor Pla of the Y. pestis pPCP1 plasmid; however, the subcutaneous injection of the CKU strain in mice did not produce any pathogenic effect. Our findings demonstrate that fast molecular detection of plague using solely the pla gene is unsuitable and should rather require Y. pestis gene marker combinations. We also suggest that the evolutionary force that might govern the expression of pathogenicity can occur through the acquisition of virulence genes but could also require the loss or the inactivation of resident genes such as antivirulence genes.
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille UniversitéMarseille, France; Centre National de la Recherche Scientifique, IRD, Mediterranean Institute of Oceanography, Aix Marseille Université, Université de Toulon, UM110Marseille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Armougom
authors.affiliation: Laboratoire VALCORE, Université M'Hamed Bougara Boumerdès Boumerdès, Algeria.
authors.forename: Idir
authors.initials: I
authors.lastname: Bitam
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Croce
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Vicky
authors.initials: V
authors.lastname: Merhej
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Lina
authors.initials: L
authors.lastname: Barassi
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Ti-Thien
authors.initials: TT
authors.lastname: Nguyen
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: La Scola
authors.affiliation: URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
keywords: Citrobacter koseri; bioinformatics; genomics and evolution; plague pathogenesis; virulence factors