Activity of lysostaphin against Staphylococcus aureus and Staphylococcus epidermidis, and their biofilms

Objective. To conduct a comparative evaluation of lysostaphin activity against isolates of S. aureus, S. epidermidis and their biofilms, obtained from orthopedic patients. Materials and methods. The study examines the effect of lysostaphin on 120 clinical bacterial isolates (30 MSSA, 30 MRSA, 30 MSSE, and 30 MRSE) alongside four reference strains of staphylococci. The minimum inhibitory concentration of lysostaphin was determined using a serial dilution method (ranging from 0.06 to 512 mg/l). The effect on biofilms and their formation was assessed by means of the O'Toole method. Data analysis was performed using GraphPad Prism software. Results. According to the results, lysostaphin exhibited twice the activity against methicillin-sensitive strains and was more effective against S. aureus compared to S. epidermidis. The studied concentrations of lysostaphin effectively prevented biofilm formation, particularly in MSSA strains. The MBIC90 value for lysostaphin was found to be four times higher for MRSE strains and twice as high for S. aureus. Additionally, the MBEC90 value of lysostaphin against S. epidermidis was 32 times greater than that observed for S. aureus. Conclusion. The pronounced anti-staphylococcal activity of lysostaphin, along with its significant destructive effect on S. aureus biofilms, offers a considerable potential for further investigation and implementation in clinical practice to combat staphylococcal infections, including those associated with various implants in orthopedics, dentistry, and cardiology.