N-Acylhomoserine lactone-dependent cell-to-cell communication and social behavior in the genus Serratia

Members of the genus Serratia are increasingly responsible for nosocomial infections, the treatment of which may be complicated by the appearance of multi-antibiotic-resistant strains. Some but not all Serratia strains and species produce N-acylhomoserine lactones (AHLs), and possess luxR and luxI homologous genes. Phylogenetic comparisons have provided evidence for the lateral transfer of these quorum-sensing systems, and in at least one strain of S. marcescens, transfer via a complex transposon has been experimentally demonstrated. AHL-dependent quorum sensing in Serratia controls population surface migration, biofilm development, the biosynthesis of a carbapenem antibiotic and production of the red pigment, prodigiosin. Serratia also possesses LuxS and produces autoinducer-2 (AI-2) which appears to function as a second quorum-sensing system controlling many of the same phenotypes as the LuxR/AHL systems.