A new antimicrobial substance produced by Staphylococcus pasteuri isolated from vegetables

Staphylococcus aureus is important food-borne pathogen in agricultural products consumed in a fresh state. The antimicrobial activities of staphylococci isolated from vegetables in Korea against S. aureus were investigated. Coagulase-negative staphylococci (CNS) isolates (12) with antimicrobial activities against S. aureus were identified as S. xylosus, pasteuri, and epidermidis. CNS isolates exhibited antimicrobial activities against Gram-positive bacteria. Inactivation of S. pasteuri antimicrobial activity by proteases suggested that the substances evaluated were antimicrobial peptides or bacteriocins. None of the S. pasteuri isolates possessed homologous DNA fragments known to be bacteriocin genes, except for nukacin. The nukM gene that encodes a post-translational modification enzyme in the nukacin gene cluster was not detected in S. pasteuri isolates. S. pasteuri probably produces one or more new antimicrobial substances.