Sélection de mutations affectant la formation de biofilm chez Actinobacillus pleuropneumoniae
A. pleuropneumoniae (App) is the causative agent of porcine pleuropneumonia, a contagious pulmonary infection in swine. Among the numerous virulence mechanisms found in bacteria, the formation of biofilms often plays an important role in pathogenesis. It has been recently demonstrated that App has the ability to form biofilms in vitro. In our laboratory, the formation of biofilms by App has been evaluated in microplates under different growth conditions. We showed that the reference strain of serotype 1 is capable of forming biofilms when cultured in a specific growth medium. The objective of this work is to identifiy genes implicated in the biosynthesis and regulation of biofilm formation in App. The objective of this study was to generate a mutant library of App using the mini-Tn10 transposon. A total of 1200 mutants has been screened with the help of in vitro models for biofilm formation which use microtiter plates or test tubes; 24 mutants exhibited modified biofilm formation when compared to the parental strain 4074NalR. The selection and identification of these mutants allowed the identification of the insertion site of the transposon. Analysis revealed novel genes implicated in biosynthesis and regulation of the biofilm formation in App. Our screen allowed the identification of genes already associated in biofilm formation of App (hns) or other pathogens (potD2, ptsI, tig and rpmF). Genes (APL_0049, APL_0637 and APL_1573) that have not yet been associated with biofilm formation were also identified. Further characterization of the genes mentioned above would permit a greater understanding of the mechanisms implicated in biofilm formation of App.
biofilm screen mutagenesis genes