title: Biofilm formation by Salmonella enterica serovar Typhimurium colonizing solid tumours.
abstract: Systemic administration of Salmonella enterica serovar Typhimurium to tumour bearing mice results in preferential colonization of the tumours and retardation of tumour growth. Although the bacteria are able to invade the tumour cells in vitro, in tumours they were never detected intracellularly. Ultrastructural analysis of Salmonella-colonized tumours revealed that the bacteria had formed biofilms. Interestingly, depletion of neutrophilic granulocytes drastically reduced biofilm formation. Obviously, bacteria form biofilms in response to the immune reactions of the host. Importantly, we tested Salmonella mutants that were no longer able to form biofilms by deleting central regulators of biofilm formation. Such bacteria could be observed intracellularly in immune cells of the host or in tumour cells. Thus, tumour colonizing S. typhimurium might form biofilms as protection against phagocytosis. Since other bacteria are behaving similarly, solid murine tumours might represent a unique model to study biofilm formation in vivo.
authors.affiliation: Molecular Immunology, HZI - Helmholtz Centre for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. kko07@helmholtz-hzi.de
authors.forename: Katja
authors.initials: K
authors.lastname: Crull
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.forename: Kathrin
authors.initials: K
authors.lastname: Westphal
authors.forename: Holger
authors.initials: H
authors.lastname: Loessner
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wolf
authors.forename: Alfonso
authors.initials: A
authors.lastname: Felipe-López
authors.forename: Michael
authors.initials: M
authors.lastname: Hensel
authors.forename: Siegfried
authors.initials: S
authors.lastname: Weiss
mesh_terms: D000818:Animals; D000898:Antibiosis; D018441:Biofilms / Q000254:growth & development*; D004195:Disease Models, Animal; D054884:Host-Pathogen Interactions; D051379:Mice; D008854:Microscopy, Electron; D009369:Neoplasms / Q000382:microbiology*; D009504:Neutrophils / Q000382:microbiology; D010587:Phagocytosis; D012481:Salmonella Infections, Animal; D012486:Salmonella typhimurium / Q000254:growth & development* / Q000276:immunology / Q000502:physiology*