| Live from the Labs cnrs I international w 10 magazine Medicine From special coatings for medical equipment to targeting bacteria directly, new research to fight nosocomial infections holds great promise. New Front against Nosocomial Infections BY Eddy Delcher Hospital-acquired—or nosocomial— infections are often caused by the accumulation of bacteria on hospital equipment and medical implants. Bacterial resistance to antibiotics, coupled with patients’ weakened immune system, make infections hard to fight, causing tens of thousands of deaths each year. To prevent such infections, a research team from the ICS1 and Inserm/Unistra2 has developed the first self-defensive coating3 for medical equipment such as catheters, the thin tubes inserted in the body to administer fluids or gases. The coating’s active component is cateslytin, a peptide with antibacterial and antifungal properties. A protective multilayer film can be formed on an implant by successively dipping it in two solutions containing polysaccharides of opposite charges. The negative ones carry cateslytin molecules and the plus/minus attraction ensures the film’s stability. Upon contact, bacteria and yeasts produce enzymes that degrade the polysaccharide film, releasing the cateslytin that prevents their growth. While not toxic to cells, the coating inhibits connective tissue adhesion and therefore can only be used on temporary implants. “We are working on coatings for permanent implants but at present, the focus is on making the coating more stable and testing it on animals,” explains Fouzia Boulmedais, who co-led the project. In another study,4 a team of researchers bridging several laboratories5 focused on the bacterium most frequently responsible for nosocomial infections, E. coli, which features extracellular appendices that carry on their tips a protein called FimH. By interacting with cell surface sugars, this protein allows the bacteria to cling onto cells and infect them. Inspired by this mechanism, the team developed a material akin to human cell surfaces by implanting sugars onto a nanodiamond support. “This material acts as a barrier on which bacteria interact instead of targeting human cells, thus preventing infection,” explains study co-author Rabah Boukherroub. “However, since we know little about the effects of nano- particles on living organisms, many in vivo studies will be required before applications can be developed.” 01. Institut Charles Sadron (CNRS / Université de Strasbourg). 02. Unité biomatériaux et bioingénierie (Inserm / Université de Strasbourg). 03. G. Cado et al., “Self-defensive biomaterial coating against bacteria and yeasts: polysaccharide multilayer film with embedded antimicrobial peptide,” Adv. Funct. Mater., 2013.doi: 10.1002/ adfm.201300416. 04. A. Barras et al., “Glycan-functionalized diamond nanoparticles as potent E. Coli anti-adhesives,” Nanoscale, 2013. 5:2307-16. 05. Institut de recherche Interdisciplinaire (IRI) (CNRS / Universités de Lille I and II), Unité de génétique de biofilms (Institut Pasteur), Laboratoire des glucides (CNRS / Université de Picardie Jules V erne). When pathogens come in contact with the biodegradable polymer coating containing cateslytin (01, green), the hyaluronidase they secrete releases cateslytin (02), which prevents the pathogens' growth. 03 Glycanfunctionalized diamond nanoparticles inhibit E. coli adhesion. 01 02 © photos : R. fabre 03 © A. BARRAS/IRI-CNRS Villeneuve-d’Ascq Strasbourg Contact information: ICS , Strasbourg. Fouzia Boulmedais > fouzia.boulmedais@ics-cnrs.unistra.fr IRI, Villeneuve-d’Ascq. Rabah Boukherroub > rabah.boukherroub@iri.univ-lille1.fr
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