title: Prophagic DNA fragments in Streptococcus agalactiae strains and association with neonatal meningitis.
abstract: We identified-by randomly amplified polymorphic DNA (RAPD) analysis at the population level followed by DNA differential display, cloning, and sequencing-three prophage DNA fragments (F5, F7, and F10) in Streptococcus agalactiae that displayed significant sequence similarity to the DNA of S. agalactiae and Streptococcus pyogenes. The F5 sequence aligned with a prophagic gene encoding the large subunit of a terminase, F7 aligned with a phage-associated cell wall hydrolase and a phage-associated lysin, and F10 aligned with a transcriptional regulator (ArpU family) and a phage-associated endonuclease. We first determined the prevalence of F5, F7, and F10 by PCR in a collection of 109 strains isolated in the 1980s and divided into two populations: one with a high risk of causing meningitis (HR group) and the other with a lower risk of causing meningitis (LR group). These fragments were significantly more prevalent in the HR group than in the LR group (P < 0.001). Our findings suggest that lysogeny has increased the ability of some S. agalactiae strains to invade the neonatal brain endothelium. We then determined the prevalence of F5, F7, and F10 by PCR in a collection of 40 strains recently isolated from neonatal meningitis cases for comparison with the cerebrospinal fluid (CSF) strains isolated in the 1980s. The prevalence of the three prophage DNA fragments was similar in these two populations isolated 15 years apart. We suggest that the prophage DNA fragments identified have remained stable in many CSF S. agalactiae strains, possibly due to their importance in virulence or fitness.
authors.affiliation: Université François-Rabelais de Tours, IFR 136-EA 3854 Bactéries et risque maternofoetal, UFR Médecine, France. n.vandermee@chu-tours.fr
authors.forename: Nathalie
authors.initials: N
authors.lastname: van der Mee-Marquet
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Domelier
authors.forename: Laurent
authors.initials: L
authors.lastname: Mereghetti
authors.forename: Philippe
authors.initials: P
authors.lastname: Lanotte
authors.forename: Agnès
authors.initials: A
authors.lastname: Rosenau
authors.forename: Willem
authors.initials: W
authors.lastname: van Leeuwen
authors.forename: Roland
authors.initials: R
authors.lastname: Quentin
mesh_terms: D001483:Base Sequence; D004279:DNA, Viral / Q000134:cerebrospinal fluid / Q000235:genetics* / Q000302:isolation & purification; D005814:Genes, Viral; D006801:Humans; D007231:Infant, Newborn; D016920:Meningitis, Bacterial / Q000382:microbiology*; D008969:Molecular Sequence Data; D039002:Prophages / Q000235:genetics* / Q000302:isolation & purification; D019105:Random Amplified Polymorphic DNA Technique; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D017108:Streptococcus Phages / Q000235:genetics* / Q000302:isolation & purification; D013292:Streptococcus agalactiae / Q000145:classification / Q000472:pathogenicity* / Q000821:virology*; D014774:Virulence / Q000235:genetics
chemical_list: D004279:DNA, Viral