Growth of the L. monocytogenes strains (in BHI at 180 rpm and 37°C) used in this study. Arrow, sampling point; wt, phage-cured EGDe strain; ΔcomK, a comK deletion mutant; ΔsigH, a sigH deletion mutant; ΔsigH+comK, a strain overexpressing comK in the sigH deletion background, +sigH, the wt strain overexpressing sigH; +sigH+comK, the wt strain overexpressing sigH and comK; ΔsigHΔcomK, a sigH and comK double deletion mutant. OD 600nm, optical density at 600 nm.