The role of σB in the stress response of Gram-positive bacteria - targets for food preservation and safety

The alternative sigma factor σB modulates the stress response of several Gram-positive bacteria, including Bacillus subtilis and the food-borne human pathogens Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. In all these bacteria, σB is responsible for the transcription of genes that can confer stress resistance to the vegetative cell. Recent findings indicate that σB also plays an important role in antibiotic resistance, pathogenesis and cellular differentiation processes such as biofilm formation and sporulation. Although there are important differences in the regulation of σB and in the set of genes regulated by σB in B. subtilis, B. cereus, L. monocytogenes and S. aureus, there are also some conserved themes. A mechanistic understanding of the σB activation processes and assessment of its regulon could provide tools for pathogen control and inactivation both in the food industry and clinical settings.