Biofilm switch and immune response determinants at early stages of infection

Biofilm development is recognized as a major virulence factor underlying most chronic bacterial infections. When a biofilm community is established, planktonic cells growing in the surroundings of a tissue switch to a sessile lifestyle and start producing a biofilm matrix. The initial steps of in vivo biofilm development are poorly characterized and difficult to assess experimentally. A great amount of in vitro evidence has shown that accumulation of high levels of cyclic dinucleotides (c-di-NMPs) is the most prevalent hallmark governing the initiation of biofilm development by bacteria. As mentioned above, recent studies also link detection of c-di-NMPs by host cells with the activation of a type I interferon immune response against bacterial infections. We discuss here c-di-NMP signaling and the host immune response in the context of the initial steps of in vivo biofilm development. © 2013 Elsevier Ltd.J. Valle was supported by Spanish Ministry of Science and Innovation ‘Ramón y Cajal’ contract. We thank Professor Angel L. Corbí and Dr Estanislao Nistal for excellent comments on the manuscript. Work in the Laboratory of Microbial Biofilms is funded by the Spanish Ministry of Economy and Competitiveness grants BIO2011-30503-C02-02, AGL2011-23954, and BFU2011-23222, as well as by ERA-NET Pathogenomics (PIM2010EPA-00606) and grants from the Departamento de Innovación (IIQ14066.RI1 and IIM13329.RI1) and Departamento de Salud (Resolución 1312/2010), Gobierno de Navarra.Peer Reviewe