In this study, the antimicrobial activity of Enterococcus strains isolated from the gut content of garden snail (Helix aspersa Müller) was investigated by agar diffusion assay. Among the 90 isolates obtained, 37 exhibited inhibitory activity against one or more of the Listeria strains tested. Based on the highest activity, 16 enterococci strains were selected for further studies. None of these strains exhibited β-hemolysis or gelatinase activity and all were sensitive to vancomycin. Treatment with lysozyme and catalase did not affect the anti-Listeria activity. Moreover, the enzymatic activity of trypsin abolished the inhibitory action of the cell-free supernatants (CFS), confirming the protein nature of the active compounds. In all cases CFS activity remained stable after heat treatment (100 ºC, 10 min). These characteristics described agree with bacteriocin type II of lactic ac...

In this study, the antimicrobial activity of Enterococcus strains isolated from the gut content of garden snail (Helix aspersa Müller) was investigated by agar diffusion assay. Among the 90 isolates obtained, 37 exhibited inhibitory activity against one or more of the Listeria strains tested. Based on the highest activity, 16 enterococci strains were selected for further studies. None of these strains exhibited β-hemolysis or gelatinase activity and all were sensitive to vancomycin. Treatment with lysozyme and catalase did not affect the anti-Listeria activity. Moreover, the enzymatic activity of trypsin abolished the inhibitory action of the cell-free supernatants (CFS), confirming the protein nature of the active compounds. In all cases CFS activity remained stable after heat treatment (100 ºC, 10 min). These characteristics described agree with bacteriocin type II of lactic ac...

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 aga...

En este estudio se evaluó la actividad antibacteriana de una cepa de Enterococcus mundtii tw278 productora de bacteriocina aislada del contenido intestinal de Hemiodema spectabilis (pepino de mar), recolectado en la costa patagónica de la Argentina. La cepa se identificó mediante pruebas bioquímicas y análisis filogenético del gen ARNr 16S. Además, se detectó el gen estructural que codifica para la mundticina KS mediante técnicas de PCR. La investigación de los factores de virulencia reveló que la cepa de E. mundtii tw278 no presentó actividad gelatinasa ni hemolítica y fue susceptible a todos los antibióticos analizados, excepto la cefalotina. La máxima actividad inhibitoria se logró al final de la fase logarítmica cuando se utilizó el caldo MRS como medio de cultivo a 35 °C. Luego de 12 h de incubación, el sobrenadante libre de células (SLC) alcanzó un título de ...