title: 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.
abstract: A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B2(1) 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, ompT(P), 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 B2(1). 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.
authors.affiliation: Laboratoire d'Etudes de Génétique Bactérienne dans les Infections de l'Enfant (EA 3105), Université Paris Diderot, Hôpital Robert Debré, 75019 Paris, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Peigne
authors.forename: Philippe
authors.initials: P
authors.lastname: Bidet
authors.forename: Farah
authors.initials: F
authors.lastname: Mahjoub-Messai
authors.forename: Céline
authors.initials: C
authors.lastname: Plainvert
authors.forename: Valérie
authors.initials: V
authors.lastname: Barbe
authors.forename: Claudine
authors.initials: C
authors.lastname: Médigue
authors.forename: Eric
authors.initials: E
authors.lastname: Frapy
authors.forename: Xavier
authors.initials: X
authors.lastname: Nassif
authors.forename: Erick
authors.initials: E
authors.lastname: Denamur
authors.forename: Edouard
authors.initials: E
authors.lastname: Bingen
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bonacorsi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016470:Bacteremia / Q000382:microbiology*; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000150:complications / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005602:France; D022761:Gene Transfer, Horizontal; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000382:microbiology*; D008581:Meningitis / Q000150:complications / Q000382:microbiology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D051381:Rats; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D026801:Synteny; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D037521:Virulence Factors