Antibacterial and antibiofilm activities of novel antimicrobial peptides against Pseudomonas aeruginosa isolates from bovine mastitis

Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most of P. aeruginosa cells can form biofilm, thereby reducing antibiotic efficacy which has become a significant public health challenge nowadays. In the present study, biofilm formation of 50 isolates was assessed. The inhibitory effect of three designed antimicrobial peptides (FASK, YDVD, WSF) on P. aeruginosa planktonic growth and biofilms was evaluated. The minimum inhibitory concentration (MIC) of all the peptides under study was 1600 µg/mL. The synthetic compounds had a significant inhibitory effect at concentrations of 1/2 MIC (800 µg/mL) and 1/4 MIC (400 µg/mL) on biofilm formation of these isolates, and showed anti-biofilm activity at a lower concentration than MIC. Antibacterial peptides FASK, YDVD with 70% antibiofilm effect and WSF with 60% effect prevented the formation of biofilm by mastitis isolates at a concentration of 1/2 MIC. The peptides of this study are promising candidates for inhibiting P. aeruginosa biofilm formation.