Probiotic characterization of Enterococcus faecium por1: Cloning, over expression of Enterocin-A and evaluation of antibacterial, anti-cancer properties

Abstract

New probiotic strain-por1 showed anti-microbial activity against a wide variety of pathogens was isolated from intestinal food content of porcupine and identified as an Enterococcus faecium (por1) by 16S rRNA sequencing. The strain E. faecium por1 was able to survive in different bile and acidic conditions, non-haemolytic. The genes responsible for virulence and subsequent pathogenicity such as cylA, cylB, esp, ace and asa1 were absent in the strain E. faecium por1 and a gene efaAfm responsible for cell wall adherence was present. Three different bacteriocins genes such as ent-A, ent-B and ent-P were identified in E. faecium por1 and in this study one of the gene ent-A was successfully cloned and overexpressed in E. coli BL21 (DE3). Further, the expressed and purified bacteriocin enterocin-A showed effective anti-bacterial and anti-biofilm activity against food born as well as human bacterial pathogens. This is the first report that a bacteriocin enterocin-A exhibited anticancer activity against human colon, gastric (HT-29, Caco-2 and AGS), cervical (HeLa) cancer cells and this bacteriocin enterocin-A was displayed no cytotoxicity toward normal intestinal epithelial cells (INT-407).