A Trimeric Autotransporter Enhances Biofilm Cohesiveness in Yersinia pseudotuberculosis but Not in Yersinia pestis.

Cohesion of biofilms made by and has been attributed solely to an extracellular polysaccharide matrix encoded by the genes (Hms-dependent extracellular matrix [Hms-ECM]). However, mutations in the BarA/UvrY/CsrB regulatory cascade enhance biofilm stability without dramatically increasing Hms-ECM production. We found that treatment with proteinase K enzyme effectively destabilized mutant biofilms, suggesting that cell-cell interactions might be mediated by protein adhesins or extracellular matrix proteins.