Enterocin Structural Gene Screening in Enterococci from Pannon White Breed Rabbits.

Abstract

This study was focused on screening the most frequently occurring enterocin (Ents) genes in faecal enterococci from the Pannon White breed of rabbits, in which this parameter never has been tested. Enterococci tested were Ent genes absent, except Enterococcus faecium EF9a, which possessed genes for four Ents. Strains produced a high amount of lactic acid (1.25 ± 0.055mmol/L, on average) and sufficiently tolerate bile. Inhibition activity of crude bacteriocin substance-partially purified (Ent, CE EF9a)-was tested against altogether 53 indicator strains. The growth of 38 strains of different staphylococcal species was not inhibited. However, the growth of fifteen other Gram-positive indicators was inhibited with inhibition activity ranged from 100 to 12,800AU/mL. Listeria monocytogenes LM 7562 was the most susceptible to CE EF9a treatment (12,800AU/mL). Molecular mass of CE EF9a ranged between 3000 and 10,000Da. After heat treatment at different temperatures and time, CE EF9a was active with the inhibition activity 12,800AU/mL. After storage of CE EF9a at different conditions, it was active even after 2-month storage at room temperature (200AU/mL against LM 7562 strain). Inhibition activity of CE EF9a after 2-month storage at 4°C was 1600AU/mL and the most stable was CE EF9a at - 20°C; the activity 12,800AU/mL was kept still after 2months. It indicates a small, thermostable substance; however, in further detail, purification analysis is necessary.