title: Phagocytosis and oxidative-burst response of planktonic Staphylococcus epidermidis RP62A and its non-slime-producing variant in human neutrophils.
abstract: The ability of bacterial organisms to produce an extracellular polysaccharide matrix known as slime has been associated with increased virulence and delayed infections in various prosthetic implants. Within a biofilm, this slime may protect the embedded bacteria from host defense mechanisms, especially phagocytosis by polymorphonuclear leukocytes. To determine whether planktonic Staphylococcus epidermidis is protected in a similar way, a novel flow cytometric assay was performed, measuring ingestion and adherence during phagocytosis and the production of superoxide during oxidative burst. Hydrophobicity was determined by hydrophobic interaction chromatography. Slime-producing S. epidermidis RP62A and its phenotypic variant, non-slime-producing RP62A-NA, were compared. The results showed increased phagocytosis of RP62A at 2, 5, 10, and 30 min; increased adherence of RP62A at 30 s and 30 min; and increased superoxide production of RP62A after 2 min. Decreased hydrophobicity of RP62A over RP62A-NA was correlated with a hydrophilic slime coat. The data argue that the host aggressively combats slime-producing S. epidermidis. This biological phenomenon is potentially important during bacteremia to prevent further adhesion, accumulation, and the genesis of a bacterial biofilm on implants or tissue surfaces.
authors.affiliation: Department of Surgery, Price Institute of Surgical Research, University of Louisville School of Medicine, Kentucky 40292, USA.
authors.forename: M
authors.initials: M
authors.lastname: Heinzelmann
authors.forename: D O
authors.initials: DO
authors.lastname: Herzig
authors.forename: B
authors.initials: B
authors.lastname: Swain
authors.forename: M A
authors.initials: MA
authors.lastname: Mercer-Jones
authors.forename: T M
authors.initials: TM
authors.lastname: Bergamini
authors.forename: H C
authors.initials: HC
authors.lastname: Polk
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002845:Chromatography / Q000379:methods; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D008853:Microscopy; D009231:Myxococcales / Q000145:classification / Q000276:immunology* / Q000378:metabolism*; D009504:Neutrophils / Q000382:microbiology*; D010587:Phagocytosis / Q000502:physiology*; D010641:Phenotype; D010933:Plankton / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst / Q000502:physiology*; D013212:Staphylococcus epidermidis / Q000145:classification / Q000276:immunology* / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D016650:Fluorescein-5-isothiocyanate