Drug releasing polyurethanes able to inhibit microbial biofilm growth on medical devices

Abstract number: s18

Donelli  G.

In recent years, a number of different strategies have been developed to prevent medical device-associated infections, including device coating with antimicrobial agents able to inhibit bacterial colonization and biofilm formation. However, the possible emergence of multi-drug-resistant microorganisms, as consequence of the sub-inhibitory antibiotic concentrations released from the implanted device, is regarded as a significant risk. On the other hand, the largely increased antibiotic resistance is a well established feature of microbial species growing in sessile mode to form a biofilm, such as Staphylococcus, Pseudomonas and Candida spp. which are the most frequently implicated bugs in device colonization. In order to inhibit microbial colonization of medical devices and to minimize multi-drug resistance, we designed experimental models based on the adsorption on functionalized polyurethanes of: (i) a water-insoluble antibiotic not used for systemic therapy; (ii) two water-soluble antibiotics, belonging to different classes, both commonly used in systemic therapy; (iii) ions of transition metals known for their broad spectrum of antimicrobial activity as possible adjuvants of antibiotics; (iv) an antifungal drug highly effective for treatment of Candida infections and (v) pore-former molecules able to improve the antibiotic loading and control its release. In particular, we developed new drug-releasing polymers loaded with: (i) usnic acid as a water-insoluble antibiotic molecule able to exert its activity at the device level; (ii) rifampin and cefamandole nafate as an association of two water-soluble antibiotics exhibiting two different modes of action; (iii) silver ions and ciprofloxacin exhibiting a synergistic role; (iv) fluconazole as a wide-spectrum antifungal drug and (v) albumin and polyethylenglycol as pore formers promoting the release of rifampin, cefamandole nafate and fluconazole from polyurethanes. The results of these in vitro studies suggest that the combined entrapping of antibiotic or antifungal drugs and pore-formers in these functionalized polyurethanes seem to be promising both in preventing bacterial colonisation and biofilm formation and controlling the emergence of microbial resistance.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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