Bactericidal synergy of lysostaphin in combination with antimicrobial peptides.

Drug-resistant staphylococci constitute a serious problem that urgently requires the discovery of new therapeutic agents. There has been a resurgence in interest in 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 certain lipopeptides used clinically (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 decrease the chances of resistance being selected. The use of lysostaphin in combination with a peptide may represent a new avenue in tackling drug-resistant staphylococci.