Antimicrobial peptide LL-37 is bactericidal against Staphylococcus aureus biofilms

Area of Science:

• Biomedical Engineering
• Infectious Diseases
• Materials Science

Background:

• Prosthetic joint infections (PJIs) pose a significant clinical challenge due to the difficulty in eradicating bacterial biofilms.
• Staphylococcus aureus is a primary pathogen responsible for biofilm formation in PJIs, necessitating novel therapeutic strategies.

Purpose of the Study:

• To evaluate the efficacy of the antimicrobial peptide LL-37 and silver nanoparticles (AgNPs) against Staphylococcus aureus biofilms.
• To compare the anti-biofilm activity of LL-37 and AgNPs with conventional antibiotics and combination therapies.

Main Methods:

• Staphylococcus aureus biofilms were cultivated on cobalt-chromium discs using a Centers for Disease Control reactor.
• Anti-biofilm activity was quantified by measuring colony-forming units (CFUs) after treatment with LL-37, AgNPs, antibiotics, and combination regimens.
• Kinetic studies assessed the rate of biofilm elimination by LL-37.

Main Results:

• LL-37 demonstrated superior efficacy, achieving a >4 log reduction in S. aureus CFUs.
• Silver nanoparticles and conventional antibiotics showed limited efficacy, with <1 log reduction in CFUs.
• Combination treatments with rifampin enhanced AgNP and gentamicin efficacy but remained less effective than LL-37 alone.

Conclusions:

• LL-37 is a highly effective agent for eradicating Staphylococcus aureus biofilms.
• LL-37 exhibits rapid S. aureus biofilm elimination kinetics.
• LL-37 holds significant potential for clinical applications in treating PJIs and combating biofilm infections.