Isolation and characterization of enterocin BC25 and occurrence of the entA gene among ruminal Gram-positive cocci

Enterocin BC25, a bacteriocin produced by Enterococcus faecium BC25 isolate d from the rumen of cow was purified to homogeneity and sequenced. Twenty a mino acids were identified in the peptide chain (TTHSGKYYGNGVYCTKNKCT), ide ntical to the N-terminal sequence of enterocin A. The DNA sequence of the e nterocin BC25 structural gene and putative immunity protein exhibited high similarity to the entA gene. The occurrence of a 726 bp amplicon containing the enterocin A structural gene was studied among garam-positive ruminal c occi by PCR. Our results showed wide occurrence of the entA structural gene among ruminal enterococcal and streptococcal bacterial strains tested, and indicate variable ability to express bacteriocin production and resistance .