Staphylococcus aureus is an important pathogen of both humans and animals, implicated in a wide range of infections. The emergence of antibiotic resistance has resulted in S. aureus strains that are resistant to almost all available antibiotics, making treatment a clinical challenge. Development of novel antimicrobial approaches is now a priority worldwide. Bacteria produce a range of antimicrobial peptides; the most diverse of these being bacteriocins. Bacteriocins are ribosomally synthesised peptides, displaying potent antimicrobial activity usually against bacteria phylogenetically related to the producer strain. Several bacteriocins have been isolated from commensal coagulase-negative staphylococci, many of which display inhibitory activity against S. aureus in vitro and in vivo. The ability of these bacteriocins to target biofilm formation and their novel mechanisms of action with efficacy against antibiotic-resistant bacteria make them strong candidates as novel therapeutic antimicrobials. The use of genome-mining tools will help to advance identification and classification of bacteriocins. This review discusses the staphylococcal-derived antimicrobial peptides displaying promise as novel treatments for S. aureus infections.

Two strains, H8/1T and H16/1AT, of Gram-stain-positive, coagulase-negative staphylococci were isolated from separate healthy domestic dogs in Scotland. Both strains were genome sequenced and their inferred DNA–DNA hybridisation indicates that H8/1T and H16/1AT represent two novel species of the genus Staphylococcus . On the basis of the results of genome sequence analysis (genome blast distance phylogeny and single nucleotide polymorphism analysis) H8/1T is most closely related to Staphylococcus devriesei and H16/1AT most closely related to Staphylococcus felis . Also, average nucleotide identity distinguished H8/1T and H16/1AT from S. devriesei and S. felis as did minor phenotypic differences. On the basis of these results, it is proposed that H8/1T and H16/1AT represent novel species with the respective names Staphylococcus caledonicus and Staphylococcus canis. The type strain of S. caledonicus is H8/1T (=NCTC 14452T=CCUG 74789T). The type strain of S. canis is H16/1AT (=NCTC 14451T=CCUG 74790T)