The antimicrobial peptide TAT-RasGAP_317-326 inhibits the formation and expansion of bacterial biofilms in vitro.

Biofilms are structured aggregates of bacteria embedded in a self-produced matrix that develop in diverse ecological niches. Pathogenic bacteria can form biofilms on surfaces and in tissues, causing nosocomial and chronic infections that are difficult to treat. While antibiotics are largely inefficient in limiting biofilm formation and expansion, antimicrobial peptides (AMPs) are emerging as alternative antibiofilm treatments. In this study, we explore the effect of the newly described AMP TAT-RasGAP <sub>317-326</sub> on Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus biofilms. Efficiency of TAT-RasGAP <sub>317-326</sub> on biofilms was tested in vitro. Both viability of bacteria contained in the biofilm as well as biomass of the biofilm were quantified using resazurin and crystal violet staining, respectively. The antibiofilm effect of TAT-RasGAP <sub>317-326</sub> was compared with a selection of classical antibiotics and AMPs. We observe that TAT-RasGAP <sub>317-326</sub> inhibits biofilm formation at concentrations equivalent or two times greater than the minimum inhibitory concentration (MIC) of planktonic bacteria. Moreover, TAT-RasGAP <sub>317-326</sub> limits the expansion of A. baumannii and P. aeruginosa established biofilms at twice the concentration inhibiting biofilm formation. These results underscore the potential use of TAT-RasGAP <sub>317-326</sub> against biofilms and encourage further studies in the development of AMPs to treat biofilm-related infections