Identification of genes for biofilm formation in a Salmonella enteritidis strain by transposon mutagenesis

Abstract:

[Objective] Biofilm plays an important role in pathogenicity of Salmonella and food poisoning caused by Salmonella. Our aim was to identify genes associated with Salmonella biofilm formation. [Methods] Seventy-four strains of Salmonella enterica serovar enteritidis (S. enteritidis), S. pullorum and S, gallinarum isolated from chickens were determined for biofilm using crystal violet staining, and the strain C050041 with well biofilm formation was chosen to construct a mutant library using transposon mutagenesis. [Results] Eighty-four percent of these Salmonella strains produced biofilm on the plastic surface. We screened 1924 mutants with transposon insertion, and 15 inserted genes were identified by growth curve determination of mutants, sequence analysis of the chromosomal DNA, and further confirmed by southern blot. These genes included metE, ompR, rpoS, rfaG, rfaJ, rfaK, rfaP, rfbH, rhlE, spiA, steB, tpx, ybdN and other two genes with unknown function. [Conclusion] We identified some new genes associated with Salmonella biofilm formation, these findings may help understand the regulation mechanism of biofilm formation and develop an attenuated Salmonella vaccine.