Antibacterial activity of a novel antimicrobial peptide [W7]KR12-KAEK derived from KR-12 against Streptococcus mutans planktonic cells and biofilms

Biofouling. 2017 Nov;33(10):835-846. doi: 10.1080/08927014.2017.1374378. Epub 2017 Oct 2.

Abstract

The aims of this study were to describe the synthesis of a novel synthetic peptide based on the primary structure of the KR-12 peptide and to evaluate its antimicrobial and anti-biofilm activities against Streptococcus mutans. The antimicrobial effect of KR-12 and [W7]KR12-KAEK was assessed by determining the minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations. The evaluation of anti-biofilm activity was assessed through total biomass quantification, colony forming unit counting and scanning electron microscopy. [W7]KR12-KAEK showed MIC and MBC values ranging from 31.25 to 7.8 and 62.5 to 15.6 μg ml-1, respectively. Furthermore, [W7]KR12-KAEK significantly reduced biofilm biomass (50-100%). Regarding cell viability, [W7]KR12-KAEK showed reductions in the number of CFUs at concentrations ranging from 62.5 to 7.8 μg ml-1 and 500 to 62.5 μg ml-1 with respect to biofilm formation and preformed biofilms, respectively. SEM micrographs of S. mutans treated with [W7]KR12-KAEK suggested damage to the bacterial surface. [W7]KR12-KAEK is demonstrated to be an antimicrobial agent to control microbial biofilms.

Keywords: Antimicrobial peptide; Streptococcus mutans; biofilm; dental caries.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Biofilms / drug effects
  • Cathelicidins / pharmacology*
  • Cell Count
  • Microbial Sensitivity Tests
  • Microscopy, Electron, Scanning
  • Peptides / metabolism
  • Streptococcus mutans / drug effects*

Substances

  • Anti-Bacterial Agents
  • Cathelicidins
  • Peptides