Recent studies in the lab performed by Nicky Caiazza, a graduate student, have revealed a role for alpha-toxin in the formation of biofilms by Staphylococcus aureus.

Shown here is the biofilms phenotype of the wild type, alpha toxin mutant (hla), and the complemented hla mutant.  Biofilm formation is quantitated by staining (and expressed as a A550 value).

The wt and hla mutant were also asessed in the flow cell (see below). These top-down phase-contrast images show the large macrocolonies formed by the wild type in the flow cell chamber (white arrows).  Only small clusters of cells are formed by the alpha toxin mutant.

Caiazza NC and O'Toole GA.  2003.  Alpha-toxin is required for biofilm formation by Staphylococcus aureus.  J Bacteriol. 185(10):3214-7