title: Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface.
abstract: The clinical importance of Acinetobacter baumannii is partly due to its natural ability to survive in the hospital environment. This persistence may be explained by its capacity to form biofilms and, interestingly, A. baumannii can form pellicles at the air-liquid interface more readily than other less pathogenic Acinetobacter species. Pellicles from twenty-six strains were morphologically classified into three groups: I) egg-shaped (27%); II) ball-shaped (50%); and III) irregular pellicles (23%). One strain representative of each group was further analysed by Brewster's Angle Microscopy to follow pellicle development, demonstrating that their formation did not require anchoring to a solid surface. Total carbohydrate analysis of the matrix showed three main components: Glucose, GlcNAc and Kdo. Dispersin B, an enzyme that hydrolyzes poly-N-acetylglucosamine (PNAG) polysaccharide, inhibited A. baumannii pellicle formation, suggesting that this exopolysaccharide contributes to pellicle formation. Also associated with the pellicle matrix were three subunits of pili assembled by chaperon-usher systems: the major CsuA/B, A1S_1510 (presented 45% of identity with the main pilin F17-A from enterotoxigenic Escherichia coli pili) and A1S_2091. The presence of both PNAG polysaccharide and pili systems in matrix of pellicles might contribute to the virulence of this emerging pathogen.
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Yassine
authors.initials: Y
authors.lastname: Nait Chabane
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Sara
authors.initials: S
authors.lastname: Marti
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Rihouey
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Alexandre
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Hardouin
authors.affiliation: Laboratory of "Microbiologie Signaux et Micro-Environnement" - Equipe d'Accueil 4312, University of Rouen, Evreux, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lesouhaitier
authors.affiliation: Department of Microbiology, Hospital Clinic, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Vila
authors.affiliation: Department of Biology, American University, Washington, District of Columbia, United States of America.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Kaplan
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Dé
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000502:physiology*; D000388:Air; D001426:Bacterial Proteins / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008853:Microscopy; D009005:Monosaccharides / Q000032:analysis
chemical_list: D001426:Bacterial Proteins; D009005:Monosaccharides