P-96: The Effect of Quorum Sensing on Bundle Forming: Pili of A. veronii bv Sobria BC88 (Pages: 82-83)

Hadi N *, Tabei SM , Shaw JG ,


Objective: Bacterial communication can be conducted by small diffusible molecules which is a widespread phenomenon in many species. This form of communication is known as quorum sensing (QS) and can regulate the gene expression of lots of biological functions such as antibiotic production; biofilm formation and virulence. Materials and Methods: Previously we have shown the contribution of Bundle forming pili (Bfp) in biofilm formation and attachment to epithelial cells in A. veronii (BC88). The hypothesis was that QS may regulate Bfp production through the regulation of main promoters of msh gene cluster. To achieve these goals, a series of ∆luxIR mutant and complemented mutant strains were constructed with the pKAGd4 promoter probe plasmids harbouring the two main promoters of the msh gene cluster and the activities of the promoters were analysed by β-galactosidase assay. Results: The ahyIR mutants had a significant reduction in their ability to adhere to epithelial cells and form biofilms when compared to the wild-type, this difference was rescued in the complemented mutants. Mutation of ahyIR had a great effect on the mshI promoter causing a large decrease in promoter activity, this was restored by complementation. Conclusion: We can conclude that QS has affected the attachment of bacteria to epithelial cells and biofilm formation, this appears to be through the direct or indirect regulation of the mshI promoter.