The end of this cycle is cell dispersion: bacteria are able to
actively detach from the community and start another colonization
cycle in a new habitat. QS signals are often involved in this active
process. The aforementioned agr system activates dispersion in St.
aureus biofilms via protease production (Boles and Horswill, 2008).
Cyclic-di-GMP indirectly represses PGA synthesis by controlling
CsrA repressor activity in E. coli (Wang et al., 2005; Jonas et al.,
2008). The norspermidine and norspermine polyamides produced
by Bacillus subtilis biofilm cells are able to disrupt St. aureus and
E. coli biofilms (Kolodkin-Gal et al., 2012).