CYCSP52 and meningitis: It has previously also been demonstrated that T6SS attenuates virulence of a STEC strain in an animal model (Wan et al., 2017), and that the T6SS effectors Hcp1 and Hcp2 contribute to binding and invasion of human brain microvascular endothelial cells of the meningitis-associated E. coli K1 strain (Zhou et al., 2012).