Role of the VirSR-VirAB system in biofilm formation of Listeria monocytogenes EGD-e

•VirS, but not VirR, is required for biofilm formation of L. monocytogenes EGD-e.•Reduced biofilm formation of the mutant strain lacking VirAB.•Neither VirS nor VirAB functions solely in biofilm formation of L. monocytogenes.•Both VirS and VirAB contribute to attachment during biofilm formation.•fla, motA and motB were downregulated in the mutant strains ΔvirAB and ΔvirS.