title: Biofilm formation by Pseudomonas aeruginosa in solid murine tumors - a novel model system.
abstract: The ability of opportunistic bacterial pathogens to grow in biofilms is decisive in the pathogenesis of chronic infectious diseases. Growth within biofilms does not only protect the bacteria against the host immune system but also from the killing by antimicrobial agents. Here, we introduce a mouse model in which intravenously administered planktonic Pseudomonas aeruginosa bacteria are enriched in transplantable subcutaneous mouse tumors. Electron microscopy images provide evidence that such bacteria reside in the tumor tissue within biofilm structures. Immunohistology furthermore demonstrated that infection of the tumor tissue elicits a host response characterized by strong neutrophilic influx. Interestingly, the biofilm defective PA14 pqsA transposon mutant formed less biofilm in vivo and was more susceptible to clearance by intravenous ciprofloxacin treatment as compared to the wild-type control. In conclusion, we have established an experimentally tractable model that may serve to identify novel bacterial and host factors important for in vivo biofilm formation and to re-evaluate bactericidal and anti-biofilm effects of currently used and novel antibacterial compounds.
authors.affiliation: Molecular Immunology, Helmholtz Center for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany. uliana.komor@helmholtz-hzi.de
authors.forename: Uliana
authors.initials: U
authors.lastname: Komor
authors.forename: Piotr
authors.initials: P
authors.lastname: Bielecki
authors.forename: Holger
authors.initials: H
authors.lastname: Loessner
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wolf
authors.forename: Kathrin
authors.initials: K
authors.lastname: Westphal
authors.forename: Siegfried
authors.initials: S
authors.lastname: Weiss
authors.forename: Susanne
authors.initials: S
authors.lastname: Häussler
mesh_terms: D042462:4-Quinolones / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms; D002939:Ciprofloxacin / Q000494:pharmacology; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial; D005260:Female; D007150:Immunohistochemistry; D008163:Luminescent Measurements; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*
chemical_list: D042462:4-Quinolones; D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin