The emergence of drug resistant bacterial strains is one of the most serious problems in modern medicine and the difficulties in finding new antibiotics make it even more challenging. The increasing resistance of bacteria in the form of both planktonic cells and biofilms established on medical devices calls for novel antibacterial strategies for the prevention and treatment of bacterial diseases. In this study, the efficiency of the commercially available antibiotic gentamicin was synergistically enhanced via the combination of two innovative strategies: i) attenuation of bacterial virulence by enzymes interfering with bacterial quorum sensing (QS), and ii) ultrasound-assisted nanotransformation of the antibacterial agent. Nanospheres of gentamicin alone were able to inhibit the growth of Gram-negative <i>Pseudomonas aeruginosa</i> by 2 logs, but did not show a potential to affect the bacterium drug resistant biofilm phenotype. On the other hand, the sonochemically generated hybrid nano-antibacterials comprising gentamicin and QS inhibiting acylase enzyme completely eradicated <i>P. aeruginosa</i> in both free floating and sessile forms. These nanospheres were also shown to penetrate within a Langmuir monolayer, composed of bacterial membrane phospholipids, confirming their capacity to interact and consequently disrupt bacterial cell membrane. The obtained hybrid nano-antibacterials with complimentary modes of action were not found innocuous towards human fibroblasts (BJ-5ta cells) in their antibacterial-effective concentrations, and therefore represent valuable alternatives to control drug-resistant biofilm associated infections at reduced antibiotic dosage.

Hybrid nano-antibacterials to control biofilm-associated infections

253rd National Meeting (2017)

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