BORDETELLA PERTUSSIS BIOFILM DEVELOPMENT. STRUCTURAL FEATURES AND BvgAS SYSTEM DEPENDENCY

D. O. SERRA; M. L. PÉREZ VIDAKOVICS; M. E. RODRÍGUEZ; A. BOSCH; O. M. YANTORNO

Institut Pasteur, Paris, Francia

Simposio; Eight International Symposium Saga of the genus Bordetella; 2006

Lab. des Bordetelles, Institut Pasteur, Paris, Francia

Bordetella pertussis is a persistent human pathogen able to form biofilms under certain in-vitro conditions. In this study, we examined the contribution of B. pertussis virulent phenotype and selected Bvg-regulated virulence factors (Filamentous hemagglutinin, Fimbriae, and Adenylate cyclase toxin) to different stages of biofilm formation. Wild type and mutant B. pertussis strains defective in the above mentioned virulence factors were cultured in continuous flow chamber systems on ZnSe windows or borosilicate coverslips. Bacterial growth and biofilm formation was monitored over time by FT-IR spectroscopy, fluorescence microscopy, and scanning laser confocal microscopy (SLCM). Microscopy images were analysed by LSM 5 Image Browser software and COMSTAT software in order to obtain quantitative information of biofilm structures. Our results indicate that the virulent phase is highly relevant for B. pertussis biofilm development on abiotic surfaces. Among the Bvg-regulated factors, FHA demonstrated to be critical not only for early attachment but also for later progress towards the development of mature biofilm. Neither Adenylate cyclase toxin nor Fimbriae were found involved in initial attachment events of B. pertussis to abiotic substrates. However, Adenylate cyclase toxin showed to play a role at later stages of biofilm growth.