Bactericidal synergy of lysostaphin in combination with antimicrobial peptides

Drug-resistant staphylococci are a serious problem that urgently requires the discovery of new therapeutic agents. There has been resurgence in interest for using lysostaphin (a specific anti-staphylococcal enzyme) as a treatment for infections caused by these important pathogens. However, bacterial resistance to lysostaphin is a problem but the use of a combination treatment may surmount this issue. In this present study, using viable counts from suspension incubations, lysostaphin is shown to be synergistically bactericidal in combination with various conventional antimicrobial peptides, the antimicrobial protein bovine lactoferrin, a lantibiotic (nisin), and clinically-used lipopeptides (colistin, daptomycin and polymyxin B). Combinations that act in synergy are of clinical importance as these reduce the doses of the compounds needed for effective treatments and, most importantly, decrease the chances of resistance being selected. The use of lysostaphin in combination with a peptide may represent a new avenue to tackling drug-resistant staphylococci.