Genetic and biochemical characterization of hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus.

Hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus, is a BsaCOL variant produced by S. hyicus 3682, a strain isolated from bovine milk. Hyicin 3682 is found in the culture supernatant, is bactericidal and its producing strain exhibits a much broader spectrum of antimicrobial activity than the producing strain of BsaCOL against several Gram-positive bacteria, which include foodborne pathogens, food-spoilage microorganisms and bacterial species of medical and veterinary importance. Sequencing of the genome of S. hyicus 3682 provided the nucleotide sequence of the entire gene cluster involved in hyicin 3682 production, which seems to be located on pRJ109, the single plasmid carried by this strain. This gene cluster is expressed and consists of 8525bp and of eight genes (hyiA, hyiB, hyiC, hyiD, hyiP, hyiF, hyiE and hyiG) encoded on the same DNA strand. The mature lantibiotic exhibits 91% identity to BsaCOL and its molecular mass was found to be ∼26Da higher due to two amino acid substitutions. S. hyicus 3682 proved to be only partially immune to its cognate bacteriocin up to 1024 AU/ml. Therefore, hyicin 3682, the first Bsa variant reported in coagulase-negative staphylococci, does exhibit antimicrobial and siblicidal activities.

Profiling and Identification of Novel Immunogenic Proteins of Staphylococcus hyicus ZC-4 by Immunoproteomic Assay.

Staphylococcus hyicus has caused great losses in the swine industry by inducing piglet exudative epidermitis (EE), sow mastitis, metritis, and other diseases and is a threat to human health. The pathogenesis of EE, sow mastitis, and metritis involves the interaction between the host and virulent protein factors of S. hyicus, however, the proteins that interact with the host, especially the host immune system, are unclear. In the present study, immunoproteomics was used to screen the immunogenic proteins of S. hyicus strain ZC-4. The cellular and secreted proteins of S. hyicus strain ZC-4 were obtained, separated by 2D gel electrophoresis, and further analyzed by western blot with S. hyicus strain ZC-4-infected swine serum. Finally, 28 specific immunogenic proteins including 15 cellular proteins and 13 secreted proteins, 26 of which were novel immunogenic proteins from S. hyicus, were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. To further verify their immunogenicity, two representative proteins (acetate kinase [cellular] and enolase [secreted]) were chosen for expression, and the resultant recombinant proteins could react with S. hyicus ZC-4-infected swine serum. In mice, both acetate kinase and enolase activated the immune response by increasing G-CSF and MCP-5 expression, and acetate kinase further activated the immune response by increasing IL-12 expression. Enolase can confer better protection against S.hycius than acetate kinase in mice. For the first time to our knowledge, our results provide detailed descriptions of the cellular and secreted proteins of S. hyicus strain ZC-4. These immunogenic proteins may contribute to investigation and elucidation of the pathogenesis of S. hyicus and provide new candidates for subunit vaccines in the future.

Hyicin 3682, a bioactive peptide produced by Staphylococcus hyicus 3682 with potential applications for food preservation.

Bacteriocins are peptides produced by bacteria and having inhibitory activity against other bacteria. Many of these substances may be useful as antibacterial agents for practical applications. In this study, 21 Staphylococcus spp. isolated from pigs, dogs and bovine milk in different states of Brazil were investigated for staphylococcin production. Hyicin 3682, a bacteriocin produced by one such strain, inhibited almost all strains tested, including Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. PCR experiments showed that hyicin 3682 is lantibiotic-related, but not identical, to both epidermin and Bsa. The maximum production of hyicin 3682 (6,400 AU/ml) was observed after 24 h of growth in BHI medium at 37 °C. Hyicin 3682 proved to be a cationic, small antimicrobial peptide with a molecular mass of 2,139 Da. It exhibited resistance to low pH and to heating at 65 °C, and partial sensitivity to proteolytic enzymes. Taken together, these results suggest that hyicin 3682, the first bacteriocin characterized in Staphylococcus hyicus, has potential biotechnological applications as a food preservative. Moreover, hyicin 3682 was able to inhibit its producer strain, suggesting that an effective immune system for specific protection against hyicin 3682 is not found in its producer strain, a characteristic not described thus far for other staphylococcins.