The transcriptional antiterminator RfaH promotes transcription of long operons encoding surface cell components important for the virulence of Escherichia coli pathogens. In this paper, we show that RfaH enhanced kps expression for the synthesis of group 2 polysialic acid capsule in E. coli K92. In addition, we demonstrate for the first time that RfaH promotes cps expression for the synthesis of colanic acid, a cell wall component with apparently no role on pathogenicity. Finally, we show a novel RfaH requirement for growth at low temperatures. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.