Biofilm formation displays intrinsic offensive and defensive features of Bacillus cereus
J Caro-Astorga, E Frenzel, JR Perkins, A Álvarez-Mena, A de Vicente, JAG Ranea, OP Kuipers, D Romero
npj Biofilms and Microbiomes (2020) 6:3
Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneﬁcial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a ﬂoating to a sessile lifestyle, to undergo further maturation of the bioﬁlm and to differentiate into the offensive or defensive features. We report that ﬂoating and bioﬁlm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, bioﬁlm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxiﬁcation machinery and production of secondary metabolites. This strategy contributes to defend bioﬁlm cells from competitors. However, ﬂoating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.