Staphylococcus epidermidis biofilm growth on polyurethanes is inhibited by the synergistic action of Dispersin B and cefamandole nafate.

Biofilm forming staphylococci are leading causative agents of medical device-associated infections, and their antibiotic treatment often fails because sessile bacteria, encased into their exopolysaccharidic matrix, are recognized to be more drug-resistant compared with the planktonic ones. In the two last decades, a number of strategies based on antiadhesive, antiseptic or antibiotic coating of polymers have been developed to prevent bacterial adhesion and biofilm formation on medical device surfaces. However, medicated devices today offered from the market are able to delay microbial colonization but not to prevent biofilm formation. More recently, alternative approaches are based on molecules able to interfere with quorum-sensing phenomena or to disperse biofilms. Interestingly, dispersin B (DspB), a β-N-acetylglucosaminidase produced by the Gram-negative periodontal pathogen Actinobacillus actinomycetemcomitans, is able to dissolve mature biofilms produced by S. epidermidis as well as by some Gram-negative bacteria.The aim of this study was the development of polymeric matrices able to bind and release DspB either alone or in combination with antimicrobial molecules. We report here that two different, properly functionalized polyurethanes are able to adsorb cefamandole nafate (CEF) and/or DspB and release them exerting an inhibitory activity against Staphylococcus epidermidis biofilm. When our functionalized polyurethanes were treated with both CEF and DspB , a synergistic action was clearly evidenced. This innovative polymer/antibiotic/Dispersin B system could represent a highly efficacious tool for preventing bacterial colonization of medical devices.