Regulation of biofilm development by Pseudomonas aeruginosa.

Karin Sauer

Abstract:

Biofilm cells differ from their planktonic counterparts in the genes and proteins that they express. We were 
able to demonstrate that in vitro and in vivo biofilm formation by P. aeruginosa occurs in a progressive and 
stage-specific manner with each developmental stage displaying a unique phenotype. To elucidate the 
mechanisms involved in the stage-specific formation of biofilms, we have begun to identify regulatory 
proteins and pathways that are critical for biofilm development using a proteomic approach. Recent progress 
in elucidating the regulatory pathways controlling biofilm development by P. aeruginosa and thus, temporal 
and stage-specific gene expression, will be summarized. Specifically, the role of regulatory proteins required 
for biofilm formation, microcolony formation, and maintenance of the planktonic mode of growth will be 
discussed. Inactivation of GacS, BflS1 and BflR2 resulted in impaired biofilm development prior to the 
stages at which these proteins were produced, in altered protein production patterns and in biofilms that 
were less resistant to antimicrobial agents. MifR was found to regulate microcolony formation while SclR 
played a role in dispersion and maintaining the planktonic mode of growth. These findings suggest the 
existence of an intricate and coordinated regulatory network involved in regulating and coordinating P. 
aeruginosa biofilm development.