Stimulation of Sessile Growth of A Biofilm-Deficient Strain Escherichia Coli K-12 by Protein(s) Secreted by Enterobacteriaceae Species

Vacheva Anna (1) , Radka Ivanova (1) , Stoitsova Stoyanka (1)

1 Institut Stephan Angeloff

In nature, most microorganisms live associated with a surface and interact with each other, thus forming structures called bioflms. They are often represented by mixed consortia of species and strains among which interaction via cell-to-cell contacts and metabolic secretion occurs. The present study examines the effects of conditioned cell-free culture supernatants (Sp) from three stationary-phase Enterobacteriaceae broth cultures on biofilm growth by the E. coli K-12 strain 446. When grown on 96- well microtitre plates in defined salt medium containing 0.04 M glucose for 24 hours, this strain formed only insignificant amount of biofilm. The supplementation of the medium with Sp from another E. coli K-12 strain did not change this. However, when Sp-s from pathogenic strains (E. coli O157 and Yersinia enterocolitica O3) were added, sessile biomass was significantly increased. Confocal laser scanning microscopy revealed better substratum coverage. The contribution of protein factors and secreted polysaccharides was examined. Treatment with proteinase K reduced biofilm stimulation of the Sp-s. Released polysaccharides were precipitated from the Sp-s, and when applied alone during biofilm growth they showed no significant influence on biofilm development. This indicates a role of protein(s) as biofilm-promoting factor(s).

Mots clés: biofilm; E. coli K-12; cell-free supernatants

Domaines: Microbiologie et Parasitologie

Vacheva Anna, Radka Ivanova, Stoitsova Stoyanka. Stimulation of Sessile Growth of A Biofilm-Deficient Strain Escherichia Coli K-12 by Protein(s) Secreted by Enterobacteriaceae Species. Biotechnology and Biotechnological Equipment, 2011, pp.on-line. ⟨10.5504/BBEQ.2011.0110⟩. ⟨pasteur-00748975⟩