Isothiocyanates (ITCs) are plant secondary metabolites with a range of biological effects including antimicrobial
activity. This study reports the activity of two ITCs [allylisothiocyanate (AITC) and 2-phenylethylisothiocyanate
(PEITC)] on bacterial motility and prevention of biofilm formation by Escherichia coli, Pseudomonas
aeruginosa, Staphylococcus aureus and Listeria monocytogenes. AITC caused total inhibition of swimming (P.
aeruginosa) and swarming (E. coli, P. aeruginosa) motilities. PEITC caused total inhibition of swimming (E. coli,
P. aeruginosa and L. monocytogenes) and swarming (E. coli and P. aeruginosa) motilities. Colony spreading of S.
aureus was completely inhibited with PEITC. Total biofilm prevention was observed for E. coli with AITC. AITC
and PEITC had no preventive effects in biofilm formation by S. aureus and L. monocytogenes, respectively.
Significant preventive action with AITC on biofilm formation by P. aeruginosa (90%) and by L. monocytogenes
(61%), and with PEITC on biofilm formation by S. aureus (75%) was verified. In terms of viability, AITC and
PEITC promoted reductions higher than 87% for all the biofilms tested. In conclusion, these molecules
demonstrated potential to inhibit bacterial motility and to prevent biofilm formation of pathogenic bacteria
