title: Interactions between polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilms on silicone implants in vivo.
abstract: Chronic infections with Pseudomonas aeruginosa persist because the bacterium forms biofilms that are tolerant to antibiotic treatment and the host immune response. Scanning electron microscopy and confocal laser scanning microscopy were used to visualize biofilm development in vivo following intraperitoneal inoculation of mice with bacteria growing on hollow silicone tubes, as well as to examine the interaction between these bacteria and the host innate immune response. Wild-type P. aeruginosa developed biofilms within 1 day that trapped and caused visible cavities in polymorphonuclear leukocytes (PMNs). In contrast, the number of cells of a P. aeruginosa rhlA mutant that cannot produce rhamnolipids was significantly reduced on the implants by day 1, and the bacteria were actively phagocytosed by infiltrating PMNs. In addition, we identified extracellular wire-like structures around the bacteria and PMNs, which we found to consist of DNA and other polymers. Here we present a novel method to study a pathogen-host interaction in detail. The data presented provide the first direct, high-resolution visualization of the failure of PMNs to protect against bacterial biofilms.
authors.affiliation: Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: van Gennip
authors.forename: Louise Dahl
authors.initials: LD
authors.lastname: Christensen
authors.forename: Morten
authors.initials: M
authors.lastname: Alhede
authors.forename: Klaus
authors.initials: K
authors.lastname: Qvortrup
authors.forename: Peter Østrup
authors.initials: PØ
authors.lastname: Jensen
authors.forename: Niels
authors.initials: N
authors.lastname: Høiby
authors.forename: Michael
authors.initials: M
authors.lastname: Givskov
authors.forename: Thomas
authors.initials: T
authors.lastname: Bjarnsholt
mesh_terms: D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000648:ultrastructure; D005260:Female; D005798:Genes, Bacterial; D006017:Glycolipids / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D054884:Host-Pathogen Interactions; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D009504:Neutrophils / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D010587:Phagocytosis; D016459:Prosthesis-Related Infections / Q000276:immunology / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000276:immunology / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D012828:Silicones
chemical_list: D004269:DNA, Bacterial; D006017:Glycolipids; D012828:Silicones; C418382:rhamnolipid