Effect of Sigma Factor ${\sigma}^{B}$ on Biofilm Formation of Listeria monocytogenes in High Osmotic and Low Temperature Conditions

Effects of sigma factor () on biofilm formation in Listeria monocytogenes 10403S and sigB null mutant were studied under high osmotic and low temperature conditions. In brain heart infusion (BHI) medium containing 6% NaCl, wild type 10403S and sigB null mutant formed biofilms of , respectively. L. monocytogenes 10403S in BHI medium containing 6% NaCl formed 4.7 times larger biofilm than without NaCl. Culture of L. monocytogenes 10403S and sigB null mutant at did not show any significant differences in biofilm formation. The results suggest biofilm formation is activated by and NaCl, whereas not affected by low temperature stress in L. monocytogenes 10403S. More studies are necessary to determine biofilm formation mechanism in osmotolerant L. monocytogenes.