the invention relates to a strain of enterococcus mundtii having probiotic qualities . the strain of e . mundtii produces an antimicrobial peptide which exhibits antimicrobial activity against a broad range of bacteria . the invention also provides an isolated nucleotide sequence which codes for the antimicrobial peptide . another aspect of the invention relates to a process for the production of a peptide of the invention which comprises cultivating enterococcus mundtii strain st4sa in a nutrient medium under micro - aerophilic conditions at a temperature of between 100c and 45 ° c ., until a recoverable quantity of said peptide is produced , and recovering said peptide . the isolated peptide of the invention may be used as an antimicrobial agent in a liquid formulation or a gel formulation as a topical treatment and may also be used as an antimicrobial agent following encapsulation in a polymer .