title: Isolation, structural characterization, and immunological evaluation of a high-molecular-weight exopolysaccharide from Staphylococcus aureus.
abstract: Colonization of implanted medical devices by coagulase-negative staphylococci such as Staphylococcus epidermidis is mediated by the bacterial polysaccharide intercellular adhesin (PIA), a polymer of beta-(1-->6)-linked glucosamine substituted with N-acetyl and O-succinyl constituents. The icaADBC locus containing the biosynthetic genes for production of PIA has been identified in both S. epidermidis and S. aureus. Whereas it is clear that PIA is a constituent that contributes to the virulence of S. epidermidis, it is less clear what role PIA plays in infection with S. aureus. Recently, identification of a novel polysaccharide antigen from S. aureus termed poly N-succinyl beta-(1-->6)-glucosamine (PNSG) has been reported. This polymer was composed of the same glycan backbone as PIA but was reported to contain a high proportion of N-succinylation rather than acetylation. We have isolated a glucosamine-containing exopolysaccharide from the constitutive over-producing MN8m strain of S. aureus in order to prepare polysaccharide-protein conjugate vaccines. In this report we demonstrate that MN8m produced a high-molecular-weight (>300,000 Da) polymer of beta-(1-->6)-linked glucosamine containing 45-60% N-acetyl, and a small amount of O-succinyl (approx 10% mole ratio to monosaccharide units). By detailed NMR analyses of polysaccharide preparations, we show that the previous identification of N-succinyl was an analytical artifact. The exopolysaccharide we have isolated is active in in vitro hemagglutination assays and is immunogenic in mice when coupled to a protein carrier. We therefore conclude that S. aureus strain MN8m produces a polymer that is chemically and biologically closely related to the PIA produced by S. epidermidis.
authors.affiliation: Departments of Virus and Cell Biology, Merck Research Laboratories, WP16-107, P.O. Box 4, West Point, PA 19486, USA. joseph_joyce@merck.com
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Joyce
authors.forename: Chitrananda
authors.initials: C
authors.lastname: Abeygunawardana
authors.forename: Qiuwei
authors.initials: Q
authors.lastname: Xu
authors.forename: James C
authors.initials: JC
authors.lastname: Cook
authors.forename: Robert
authors.initials: R
authors.lastname: Hepler
authors.forename: Craig T
authors.initials: CT
authors.lastname: Przysiecki
authors.forename: Karen M
authors.initials: KM
authors.lastname: Grimm
authors.forename: Keith
authors.initials: K
authors.lastname: Roper
authors.forename: Charlotte C Yu
authors.initials: CC
authors.lastname: Ip
authors.forename: Leslie
authors.initials: L
authors.lastname: Cope
authors.forename: Donna
authors.initials: D
authors.lastname: Montgomery
authors.forename: Mason
authors.initials: M
authors.lastname: Chang
authors.forename: Sherilyn
authors.initials: S
authors.lastname: Campie
authors.forename: Martha
authors.initials: M
authors.lastname: Brown
authors.forename: Tessie B
authors.initials: TB
authors.lastname: McNeely
authors.forename: Julie
authors.initials: J
authors.lastname: Zorman
authors.forename: Tomas
authors.initials: T
authors.lastname: Maira-Litrán
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Pier
authors.forename: Paul M
authors.initials: PM
authors.lastname: Keller
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.forename: George E
authors.initials: GE
authors.lastname: Mark
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002850:Chromatography, Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006386:Hemagglutination Tests; D007982:Levulinic Acids / Q000032:analysis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008970:Molecular Weight; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification*; D013211:Staphylococcus aureus / Q000737:chemistry*
chemical_list: D007982:Levulinic Acids; D011135:Polysaccharides, Bacterial; C032246:levulinic acid