Isolation of bacteriocinogenic Enterococcus mundtii strain from Hemiodema spectabilis (sea cucumber)

Abstract

This study was conducted to evaluate the antibacterial activity of a bacteriocinproducing Enterococcus mundtii tw278 strain isolated from the intestinal content of Hemiodema spectabilis (sea cucumber) sampled in the Patagonian coast of Argentine. The strain was identified by biochemical tests and 16S rRNA gene phylogenetic analyses. The structural gene that codifies mundticin KS was detected by PCR. Investigation of virulence factors revealed that E. mundtii tw278 did not display gelatinase or hemolytic activity and was susceptible to all antibiotics assayed, except cefalotin. Maximum inhibitory activity was achieved at the end of logarithmic phase when MRS broth was used as culture media at 35 °C. After 12 h of incubation, cell-free supernatant (CFS) reached a titre of 163 840 arbitrary units per mililitre against the target bacteria Listeria innocua ATCC 33090. CFS showed activity against all the Listeria strains assayed, Enterococcus faecalis ATCC 29212, vancomycin-resistant enterococci (Van A, Van B and Van C), Lactobacillus plantarum TwLb 5 and Vibrio anguilarum V10. This would be the first study to report the isolation of a bacteriocinogenic E. mundtii strain from intestinal content of Hemiodema spectabilis.