Enhanced eradication of Pseudomonas aeruginosa bio-films by using ultrasound combined with neutrophil and antibiotics

Abstract Device-associated infection is becoming a major threat to patient health associated with the extensive use of indwelling medical devices. Bacterial biofilms formed on the surfaces of indwelling devices act as physical and biochemical barriers to protect bacterial cells from being killed by antibiotics and host-immune mediators. Although ultrasound (US) alone cannot destroy mature biofilms, it can sensitize Pseudomonas aeruginosa (P. aeruginosa) to gentamicin and disrupt the expression of genes associated with bacterial metabolism, motility, antibiotic resistance, virulence and quorum sensing involved in biofilm formation. Furthermore, by evaluating levels of reactive oxygen species in neutrophils, we showed that US may promote neutrophil phagocytosis of bacteria. Therefore, in addition to preventing the formation of P. aeruginosa biofilms in an amplitude-dependent manner, US can effectively destroy mature biofilms in combination with gentamicin and neutrophils. These results may have great potential for the treatment of device-associated infections.