The CtsR regulator controls the expression of clpC, clpE and clpP and is required for the virulence of Enterococcus faecalis in an invertebrate model.

The intrinsic ruggedness of Enterococcus faecalis is responsible for its widespread distribution in nature and is often viewed as an important virulence determinant. Previously, we showed that the ClpB ATPase is negatively regulated by CtsR and is required for thermotolerance and virulence in a Galleria mellonella invertebrate model. Here, we used in silico, Northern blot and quantitative real-time PCR analyses to identify additional members of the CtsR regulon, namely the clpP peptidase and the clpC and clpE ATPases. When compared to the parent strain, virulence of the ΔctsR strain in G. mellonella was significantly attenuated.