The Enterococcus secretome inhibits the growth of vancomycin-resistant Enterococcus faecalis V853 with their antiproliferative properties and nanoencapsulation effects.

Abstract

In our study, the secretome of the clinical isolate Enterococcus faecalis HY7 displayed antibacterial activity against the vancomycin-resistant Enterococcus faecalis V853. These bacteriocin-like substances showed thermal stability at a wide range of temperatures up to 121 °C, while proteinase K treatment resulted in a total loss of their activity. PCR-based screening for bacteriocin biosynthetic genes revealed that Enterococcus faecalis HY7 harbored multiple enterocin-producing genes, including ent A, avc A, and as-48. The production kinetics demonstrated the highest levels of bacteriocins production at 16 h, whereas the activity was diminished after 32 h of microbial growth. Notably, the partially purified bacteriocins exhibited anti-proliferative activity on the colon cancer cells, Caco2, with an IC50 value of 172.8 μg/mL. Remarkably, the nanoencapsulation of our bacteriocins in liposome showed a fourfold increase in its anti-vancomycin-resistant Enterococcus activity, which is the first report of liposome encapsulation with anti-vancomycin resistant Enterococcus bacteriocin.