Many enterococcal strains produce bacteriocins, which could be useful as natural 
food preservatives through inhibition of pathogenic and spoilage microorganisms. 
There is little knowledge of the distribution and spectrum of bacteriocin 
activity and the distribution of bacteriocin-encoding genes in enterococci 
isolated from dogs. Therefore, we subjected 160 enterococcal isolates (E. 
faecium n=92, E. faecalis n=35, E. hirae n=28, E. casseliflavus n=3, E. mundtii 
n=2) from 105 samples of dog faeces to polymerase chain reaction (PCR) detection 
of genes for enterocin A, P, B, L50A, L50B, AS-48, and bac31 and to screening 
for bacteriocin activity. The results showed the presence of at least one of the 
tested genes in 54/160 isolates, with E. faecium the most common gene-possessing 
species. The most frequently occurring gene for production of enterocin A was 
observed in combination with enterocin P and B. Bacteriocin activity was 
observed in 76/160 isolates against at least one of 5 indicator bacteria from 
the genus Listeria, Enterococcus, Streptococcus and Staphylococcus. Four 
selected strains (IK25, Bri, I/Dz, P10) were active mostly against different 
species of Enterococcus (in the range 400-25 600 AU/mL) and Listeria sp. 
(800-12 800 AU/mL) but no Gram-negative bacteria were inhibited. Protein 
character, thermostability (up to 121°C) and stability at different pH values 
(3.0-10.0) were confirmed for crude bacteriocins of these four strains. The 
antimicrobial substance of E. faecium IK25 strain was identified as enterocin B 
using molecular weight detection and the presence of genes.