Cholate-stimulated biofilm formation by Lactococcus lactis cells

Arsalan Haseeb Zaidi, Patrick J Bakkes, Bastiaan P Krom, Henny C van der Mei, Arnold J M Driessen

Research output: Contribution to JournalArticleAcademicpeer-review


Bile acid resistance by Lactococcus lactis depends on the ABC-type multidrug transporter LmrCD. Upon deletion of the lmrCD genes, cells can reacquire bile acid resistance upon prolonged exposure to cholate, yielding the ΔlmrCD(r) strain. The resistance mechanism in this strain is non-transporter based. Instead, cells show a high tendency to flocculate, suggesting cell surface alterations. Contact angle measurements demonstrate that the ΔlmrCD(r) cells are equipped with an increased cell surface hydrophilicity compared to those of the parental and wild-type strains, while the surface hydrophilicity is reduced in the presence of cholate. ΔlmrCD(r) cells are poor in biofilm formation on a hydrophobic polystyrene surface, but in the presence of subinhibitory concentrations of cholate, biofilm formation is strongly stimulated. Biofilm cells show an enhanced extracellular polymeric substance production and are highly resistant to bile acids. These data suggest that non-transporter-based cholate resistance in L. lactis is due to alterations in the cell surface that stimulate cells to form resistant biofilms.

Original languageEnglish
Pages (from-to)2602-10
Number of pages9
JournalApplied and Environmental Microbiology
Issue number8
Publication statusPublished - Apr 2011


  • ATP-Binding Cassette Transporters/genetics
  • Bile Acids and Salts/pharmacology
  • Biofilms/drug effects
  • Cell Membrane/drug effects
  • Cholates/pharmacology
  • Drug Resistance, Multiple, Bacterial
  • Gene Expression Regulation, Bacterial/drug effects
  • Hydrophobic and Hydrophilic Interactions
  • Lactococcus lactis/drug effects
  • Membrane Transport Proteins/genetics
  • Microscopy, Confocal
  • Multidrug Resistance-Associated Proteins/genetics


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