Extracellular protease in Actinomycetes culture supernatants inhibits and detaches Staphylococcus aureus biofilm formation

Abstract

Bacterial biofilms are associated with chronic infections due to their resistance to antimicrobial agents. Staphylococcus aureus is a versatile human pathogen and can form biofilms on human tissues and diverse medical devices. To identify novel biofilm inhibitors of S. aureus, the supernatants from a library of 458 Actinomycetes strains were screened. The culture supernatants (1% v/v) of more than 10 Actinomycetes strains inhibited S. aureus biofilm formation by more than 80% without affecting the growth. The culture supernatants of these biofilm-reducing Actinomycetes strains contained a protease (equivalent to 0.1 μg proteinase K ml⁻¹), which both inhibited S. aureus biofilm formation and detached pre-existing S. aureus biofilms. This study suggests that protease treatment could be a feasible tool to reduce and eradicate S. aureus biofilms.