Inhibition of bacterial adhesion and biofilm formation of sulfonated chitosan against Pseudomonas aeruginosa

The exploitation of chitosan derivatives as safe and natural polymers against microorganisms has been reconsidered as an alternative to antibiotics and chemical preservatives. Herein, inhibition of bacterial adhesion and biofilm formation by anionic chitosan (sulfonated chitosan, SCS) and cationic chitosan (chitosan hydrochloride, WCS) against P. aeruginosa were investigated. The results showed SCS exhibited good antibacterial activity with 1 mg/mL MIC and 8 mg/mL MBC, while MIC and MBC of WCS were 1 mg/mL and 16 mg/mL, respectively. The metabolic activity and secretion of exopolysaccharide in biofilm of P. aeruginosa were significantly decreased after the treatment with SCS. Scanning electron microscopy and confocal laser scanning microscopy further demonstrated that SCS and WCS could significantly inhibit the biofilm formation in a concentration-dependent mode. Overall, these results suggest that WCS and SCS are useful to inhibit the biofilm formation of P. aeruginosa, and would be potential alternatives for the control of bacterial pathogens in food industry.