Cell surface physico chemistry alters biofilm development of Pseudomonas aeruginosa lipopolysaccharide mutants

Abstract

The hydrophobic and electrostatic characteristics of bacterial cell surfaces were compared with attachment proclivity and biomass accumulation over time between wildtype Pseudomonas aeruginosa serotype O6 (possesses A and B band LPS), and three LPS-deficient mutants, vi;. A28 (A(+)B(-)), R5 (A(+)B(-)), and Gt700 (A(-)B(-)). The hydrophobic character of each serotype was determined by hydrophobic interaction chromatography and salt-aggregation, and strains were ranked similarly by each method, viz. R5 greater than or equal to A28 > Gt700 > O6. The anionic characteristics of cell-surfaces were determined by electrostatic interaction chromatography and by zeta-potential measurements, and ranked R5 > A28 greater than or equal to Gt700 > O6. Adhesion and biofilm accumulation on stainless steel were significantly different between strains, following the order R5 > A28 much greater than O6 > Gt700. Biofilm rankings were similar on glass, a second hydrophilic substratum. The mutant strains with a strongly hydrophobic character (R5 and A28) demonstrated a significantly greater capacity to form biofilms. These adherent mutants also appeared to have a more anionic cell surface, which may have played a role in biofilm formation on the hydrophilic substrata