Idalina Machado, Laurent Coquet, Maria Olivia Pereira and Thierry Jouenne
This work investigates the outer membrane (OM) proteomic alteration of Pseudomonas aeruginosa biofilm cells after adaptation to benzalkonium chloride (BC) and ciprofloxacin (CIP). Biofilms were formed in 6-well plates for 24 h being after submitted to 324 mg/L BC and 6.0 mg/L CIP, during 12 days. Cells were harvested, the OM proteins extracted and patterns compared. P. aeruginosa adaptation altered the total amount of six proteins, about 10% of the discriminated proteins on two-dimensional gels. Exposure to both antimicrobials generated a common downregulation of three proteins, GroEL, the major capsid protein and the putative tail sheath protein. The type 4 fimbrial biogenesis outer membrane protein PilQ precursor was over-expressed only in biofilm cells submitted to BC, while the probable bacteriophage protein and the hypothetical protein PA0537 were overexpressed in CIP exposed biofilm cells. The alterations in OMPs expression might be involved in the biofilm bacteria high resistance to antimicrobial agents.