Device coating with antimicrobial agents able to inhibit microbial colonisation and biofilm formation represents a pivotal approach in the prevention of medical device-associated infections. Existing antiseptic or antibiotic loaded devices mainly suffer from a relatively short persistence of antimicrobial action as consequence of an early and rapid drug release. On the other hand, the most frequently implicated bugs in device colonisation, such as Staphylococcus, Pseudomonas and Candida spp, are known to develop a largely increased antibiotic resistance due to their sessile mode of growth to form a biofilm. These issues are both critical for the management of patients in clinical settings and need the development of innovative and safer medical devices refractory to microbial adhesion and biofilm formation. To this aim, we designed and tested in vitro experimental models based on the adsorption on functionalised polymers of: i) a water-insoluble antibiotic active at device level and not used for systemic therapy; ii) pore-former molecules able to modulate drug loading and release; iii) transition metal ions able to synergistically act together with antibiotics. In particular, we developed new drug-releasing polyurethanes loaded with: i) usnic acid as a water-insoluble drug able to exert antibiofilm activity against Gram-positives and to interfere with quorum-sensing phenomena in Gram-negatives; ii) albumin and polyethylene glycol as porogens promoting the release of rifampin, cefamandole nafate and fluconazole from polyurethanes; iii) silver ions and ciprofloxacin exhibiting a long-lasting antibacterial synergistic activity against Gram-positives and Gram-negatives. Combined entrapping within our functionalised polyurethanes of antibiotic/antifungal drugs and transition metal ions, when needed in conjunction with porogens as drug release modulators, seem to offer promising strategies both in prevention of bacterial colonisation and biofilm formation and control of drug resistance.
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|Titolo:||NOVEL STRATEGIES TO CONTROL BIOFILM FORMATION ON MEDICAL DEVICES.|
|Data di pubblicazione:||2007|
|Appartiene alla tipologia:||04a Atto di comunicazione a congresso|