In this month’s issue of the Journal of Bacteriology, Jones et al. (1) examine the relationship between the Pseudomonas aeruginosa chronically produced exopolysaccharide, alginate, and a polysaccharide that is produced during the initial stages of biofilm formation, Psl. Psl, composed of mannose, rhamnose, and glucose, was identified as one of the first exopolysaccharides in nonmucoid biofilm m...