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Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface.

Nait Chabane Y, Marti S, Rihouey C, Alexandre S, Hardouin J, Lesouhaitier O, Vila J, Kaplan JB, Jouenne T, Dé E - PLoS ONE (2014)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.

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.

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Biofilm formation by A. baumannii.A) Strain negative for pellicle formation (turbid culture); B) Strain forming a pellicle on the top of the liquid media (culture broth transparent); C) Inverted tube to examine pellicle strength.
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pone-0111660-g001: Biofilm formation by A. baumannii.A) Strain negative for pellicle formation (turbid culture); B) Strain forming a pellicle on the top of the liquid media (culture broth transparent); C) Inverted tube to examine pellicle strength.

Mentions: Standing 2 mL cultures in MHB were grown for 72 h in polystyrene tubes (Ø 13 mm × H 75 mm). Pellicle formation was identified visually (Figure 1); isolates were considered positive when the surface of the culture was covered with an opaque layer. Pellicle cohesion was examined by manually inverting the tubes (Figure 1C). The experiments were performed in duplicate at three independent time-points.


Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface.

Nait Chabane Y, Marti S, Rihouey C, Alexandre S, Hardouin J, Lesouhaitier O, Vila J, Kaplan JB, Jouenne T, Dé E - PLoS ONE (2014)

Biofilm formation by A. baumannii.A) Strain negative for pellicle formation (turbid culture); B) Strain forming a pellicle on the top of the liquid media (culture broth transparent); C) Inverted tube to examine pellicle strength.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216135&req=5

pone-0111660-g001: Biofilm formation by A. baumannii.A) Strain negative for pellicle formation (turbid culture); B) Strain forming a pellicle on the top of the liquid media (culture broth transparent); C) Inverted tube to examine pellicle strength.
Mentions: Standing 2 mL cultures in MHB were grown for 72 h in polystyrene tubes (Ø 13 mm × H 75 mm). Pellicle formation was identified visually (Figure 1); isolates were considered positive when the surface of the culture was covered with an opaque layer. Pellicle cohesion was examined by manually inverting the tubes (Figure 1C). The experiments were performed in duplicate at three independent time-points.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Unité Mixte de Recherche 6270 CNRS - Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, Mont-Saint-Aignan, France.

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.

Show MeSH
Related in: MedlinePlus