Antimicrobial dendrimer active against Escherichia coli biofilms.

We have investigated the ability of a previously reported antimicrobial peptide dendrimer (RW)(4D) to inactivate Escherichia coli RP437 in planktonic culture and in biofilms. The results show that the dendrimer inhibits bacterial growth in both planktonic and biofilm states. Live/Dead staining assays reveal that most bacteria in a preformed biofilm lose viability after treatment with this peptide. This result is in marked contrast to most existing reports that antimicrobial peptides are ineffective against mature bacterial biofilms.