Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/9/2012
Publication Date: 11/12/2012
Citation: Nicholson, T.L., Conover, M.S., Deora, R. 2012. Transcriptome profiling reveals stage-specific production and requirement of flagella during biofilm development in Bordetella bronchiseptica. PLoS ONE. 7(11):e49166. Interpretive Summary: Bacterial colonization of both biological and non-biological surfaces followed by survival or persistence is often linked to the development of attached microbial communities known as biofilms. B. bronchiseptica naturally infects a wide variety of animal species and is frequently isolated from the nasal cavities of vaccinated animals suggesting that vaccines fail to protect animals from infections. One explanation for this vaccine failure is that B. bronchiseptica exists as biofilms. Biofilm formation is an increasingly appreciated means by which bacteria can avoid detection and clearance by the host and also providing enhanced persistence in the environment. Here we show that B. bronchiseptica carefully regulates the production of several gene products in a coordinated manner to produce biofilms to facilitate colonization in the host. Together these results demonstrate that flagella production at the appropriate stage of biofilm development is required for biofilm formation and maturation. This provides important insight as to how a bacterial pathogen regulates the production of virulence factors to establish a biofilm mode of existence, thereby evading immunity and immune clearance mechanisms. Targeting flagella for future vaccines may provide a new and improved method to prevent biofilm formation and subsequent infections and secondary bacterial infections in many species.
Technical Abstract: In this report we have used microarray analysis to study the transcriptome of B. bronchiseptica over the course of five time points representing distinct stages of biofilm development. The results suggest that B. bronchiseptica undergoes a coordinately regulated gene expression program similar to a bacterial developmental process. Additionally, our analysis led to the discovery that expression and subsequent production of the genes encoding flagella, a classical Bvg- phase phenotype, occurs and is under tight regulatory control during B. bronchiseptica biofilm development. Using mutational analysis in a combination of several continuous flow and static biofilm experiments, we confirmed the microarray data and demonstrate that flagella production at the appropriate stage of biofilm development, i.e. production early subsequently followed by repression, is required for robust biofilm formation and maturation. In addition, our results suggest that the regulatory mechanism coordinating biofilm development in B. bronchiseptica can function independently from the BvgAS regulatory system.