The Natural Antimicrobial Peptide Subtilosin Acts Synergistically with Glycerol Monolaurate, Lauric Arginate, and ε-Poly- l -Lysine against Bacterial Vaginosis-Associated Pathogens but Not Human Lactobacilli

Subtilosin is a cyclical antimicrobial peptide produced by Bacillus amyloliquefaciens that has antimicrobial activity against the bacterial vaginosis-associated human pathogen Gardnerella vaginalis. The ability of subtilosin to inhibit G. vaginalis alone and in combination with the natural antimicrobial agents glycerol monolaurate (Lauricidin), lauric arginate, and ε-poly-L-lysine was tested using a checkerboard approach. Subtilosin was found to act synergistically with all of the chosen antimicrobials. These promising results indicate that lower concentrations of subtilosin in combination with other compounds could effectively be used to inhibit growth of the pathogen, thereby decreasing the risk of developed antimicrobial resistance. This is the first report on the effects of subtilosin combined with other natural antimicrobials against G. vaginalis.