Ultrasound-targeted microbubble destruction enhances human β-defensin 3 activity against antibiotic-resistant Staphylococcus biofilms.

The infection of orthopedic implantation devices with Staphylococcus is a serious concern within the biomaterial community. Treatments are not always successful because of antibiotic-resistant bacteria and serious biofilm infections. Human β-defensin 3 (hBD-3) is considered to be the most promising class of defensin antimicrobial peptides and its effect on antibiotic-resistant Staphylococcus biofilms, combined with ultrasound (US)-targeted microbubble (MB) destruction (UTMD), has not been reported. In the study, we found that biofilm densities, the percentage of live cells and the viable counts of two tested Staphylococcus recovered from the biofilm were significantly decreased in the maximum concentration hBD-3 combined with UTMD compared with those of any other groups. Furthermore, results suggested that UTMD could also enhance 1MIC hBD-3 activity inhibiting the biofilm-associated genes expression of icaAD and the methicillin-resistance genes expression of MecA by simultaneously promoting the icaR expression. UTMD may have great potential for improving antibiotic activity against biofilm infections.