INHIBITION EFFECT OF ENTEROCIN CCM-4231 IN THE RUMEN FLUID ENVIRONMENT

Enterocin CCM 4231 is a bacteriocin with a broad antimicrobial spectru m produced by the ruminal strain Enterococcus faecium CCM 4231. Its in hibitory effect towards enterococci, Ent. faecium EF 26/42, staphyloco cci, Streptococcus bovis AO 24/85 and Escherichia coli, as well as tow ards Listeria monocytogenes OHIO strain, in the rumen fluid environmen t was studied during culture at 37 and 30 degrees C for 24 h and 20 da ys. Enterocin CCM 4231 was added to the samples at a concentration of 3200 AU ml(-1). The best inhibitory effect was noted against enterococ ci at both cultivation temperatures. A decrease in total cell count fr om 10(8) cfu ml(-1) to 10(4) cfu ml(-1) and from 10(5) cfu ml(-1) to 1 0(1) cfu ml(-1) was detected. Addition of enterocin to the rumen fluid also inhibited staphylococci (from 10(5) cfu ml(-1) to 10(4) cfu ml(- 1) and/or 10(3) cfu ml(-1)). Gram-negative E. coli cells were inhibite d at both cultivation temperatures (decrease from 10(6) cfu ml(-1) to 10(4) cfu ml(-1) at 37 degrees C, and from 10(4) cfu ml(-1) to 10(5) c fu ml(-1) at 30 degrees C). Enterococcus faecium EF 26/42 and Streptoc occus bovis AO 24/85, the strains growing in the rumen fluid, were the most sensitive to the addition of enterocin during the first 24 h of fermentation (decrease from 10(10) cfu ml(-1) and 10(8) cfu ml(-1) to 10(6) cfu ml(-1) and 10(4) cfu ml(-1)). An antilisterial effect of the bacteriocin was also confirmed. Further application of bacteriocin in ruminal ecology was indicated.