High in vitro antibacterial activity of Pac-525 against Porphyromonas gingivalis biofilms cultured on titanium

Abstract

In order to investigate the potential of short antimicrobial peptides (AMPs) as alternative antibacterial agents during the treatment of peri-implantitis, the cytotoxic activity of three short AMPs, that is, Pac-525, KSL-W, and KSL, was determined using the MTT assay. The antimicrobial activity of these AMPs, ranging in concentration from 0.0039mg/mL to 0.5mg/mL, against the predominant planktonic pathogens, including Streptococcus sanguis, Fusobacterium nucleatum, and Porphyromonas gingivalis, involved in peri-implantitis was investigated. Furthermore, 2-day-old P. gingivalis biofilms cultured on titanium surfaces were treated with Pac-525 and subsequently observed and analysed using confocal laser scanning microscopy (CLSM). The average cell proliferation curve indicated that there was no cytotoxicity due to the three short AMPs.The minimum inhibitory concentration and minimum bactericidal concentration values of Pac-525 were 0.0625mg/mL and 0.125mg/mL, respectively, for P. gingivalis and 0.0078mg/mL and 0.0156mg/mL, respectively, for F. nucleatum. Using CLSM, we confirmed that compared to 0.1% chlorhexidine, 0.5mg/mL of Pac-525 caused a significant decrease in biofilm thickness and a decline in the percentage of live bacteria.These data indicate that Pac-525 has unique properties that might make it suitable for the inhibition the growth of pathogenic bacteria around dental implants.