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International audience; We developed a chemical method to covalently functionalize cellulose nanofibers and cellulose paper with mannoside ligands displaying a strong affinity for the FimH adhesin from pathogenic E. coli strains. Mannose-grafted cellulose proved efficient to selectively bind FimH lectin and discriminate pathogenic E. coli strains from non-pathogenic ones. These modified papers are valuable tools for diagnosing infections promoted by E.coli, such as cystitis or inflammatory bowel diseases, and the concept may be applicable to other life-threatening pathogens. The worldwide spread of antibiotic resistances raises serious health problems, and has driven the identification of new virulence factors and development of alternative antibacterial therapeutics. Mannose-binding FimH adhesin, expressed by Escherichia coli strains has been extensively studied as a target for disrupting bacterial attachment to the host cells. 1 Impressive results were obtained in the context of urinary tract infections (UTI), a prevalent infection type generally mediated by the attachment of uropathogenic E. coli strains (UPEC) to the highly mannosylated uroplakin transmembrane protein of urothelial lining cells. FimH antagonists orally administered to in vivo UTI mouse models, were shown to decrease the E.coli load in the bladder by several orders of magnitude, 2-4 making them competitive with conventional antibiotic treatment. 5,6 This concept was more recently extended to Crohn's disease (CD), an inflammatory disorder of the intestine where an altered gut microbiota, particularly the presence of adherent-invasive E. coli strains (AIEC), is suspected to play a key role in the pathogenesis. 7 Synthetic derivatives of heptylmannoside (HMan), a nanomolar FimH antagonist, 8 were shown to lower the AIEC bacterial level, signs of colitis and gut inflammation when administered per os (10 mg/kg) in CD mouse models. 9,10 Sensitive and rapid diagnostic systems are essential to evaluate the presence of E. coli expressing FimH adhesin in gut microenvironments in order to properly stratify patients before treatment. While the high prevalence of UPEC in the normally sterile urinary tract environment facilitates diagnosis, the AIEC niche is more complex, located at the ileal mucosa in 21 to 63% of CD patients, 11,12 within an ecological community of hundreds of symbiotic microorganisms. Furthermore, no specific biomarkers are currently effective at distinguishing AIEC from other commensal E. coli of the gut microbiota. Previously, it has been shown that AIEC pathobiont possesses specific allelic variants in the fimH gene, conferring them a high ability to adhere in vitro and to colonize the gut of CEABAC10 mice. 13 Establishing an approach to discriminate the strong mannose-binders from other bacteria would therefore be of tremendous importance for efficient diagnosis. In this work, we developed a heterogeneous support to specifically trap and accumulate pathogenic E.coli from biological fluids. Heptyl-α-D-mannoside (HMan) was grafted by click chemistry techniques onto cellulose nanofibers (CN) and cellulose paper (CP). HMan was previously identified as a potent binder of the isolated FimH lectin domain. 8 It should be noted that the lectin domain represents the high-affinity state of FimH under mechanical force and that full-length FimH display a lower affinity for mannosides. 14,15 Covalently functionalized CN or CP were characterized by Fourier transform spectroscopy (FTIR), elemental analysis, X-ray photo-electron spectrometry (XPS), and scanning electron microscopy (SEM). HMan-CN was first compared in vitro against CN grafted with lower FimH affinity ligands i.e. Man-CN lacking the hydrophobic heptyl chain, and HGlc-CN an analog with a glucose sugar that is not recognized by FimH lectin (Scheme 1). In addition, we switched the anomeric oxygen atom to a sulfur and synthesized HSMan-CN to prevent potential sugar hydrolysis from the surface by mannosidases. The modified CN were first assessed for their faculty to bind FimH and to prevent AIEC adhesion to intestinal cells. HMan-CN was then orally administered to the CEABAC10 mouse model of CD to assess its capacity to decrease AIEC in the feces of AIEC-infected mice and to act as a potential CD therapeutic. HM was next coated on CP and the capacity of the HMan-CP to selectively catch AIEC in solution was analyzed. Scheme 1. Chemical synthesis of the sugar-coated cellulose fibers.

Point-of-care (POC) detection and diagnostic platforms provide critical information about health and safety conditions in austere and resource-limited settings in which medical, military, and disaster relief operations are conducted. In this work, low-cost paper materials commonly used in POC devices are coated with liquid-infused polymer surfaces and folded to produce geometries that precisely localize complex liquid samples undergoing concentration by evaporation. Liquid-infused polymer surfaces were fabricated by infusing silicone-coated paper with a chemically compatible polydimethylsiloxane oil to create a liquid overlayer. Tests on these surfaces showed no remaining bacterial cells after exposure to a sliding droplet containing a concentrated solution of Escherichia coli or Staphylococcus aureus, while samples without a liquid layer showed adhesion of both microdroplets and individual bacterial cells. Folding of the paper substrates with liquid-infused polymer surfaces into several functional 3D geometries enabled a clean separation and simultaneous concentration of a liquid containing rhodamine dye into discrete, predefined locations. When used with bacteria, which are known for their ability to adhere to nearly any surface type, functional geometries with liquid-infused polymer surfaces concentrated the cells at levels significantly higher than geometries with dry control surfaces. These results show the potential of synergistically combining paper-based materials with liquid-infused polymer surfaces for the manipulation and handling of complex samples, which may help the future engineering of POC devices.

The aim of the present study is to evaluate the probiotic attributes of Bacillus subtilis AMS6 isolated from fermented soybean (Churpi). This isolate exhibited tolerance to low pH (pH 2.0) and bile salt (0.3%), capability to autoaggregate and coaggregate. AMS6 also showed highest antibacterial activity against the pathogenic indicator strain Salmonella enterica typhimurium (MTCC 1252) and susceptibility towards different antibiotics tested. The isolate was effective in inhibiting the adherence of food borne pathogens to Caco-2 epithelial cell lines, and was also found to be non-hemolytic which further strengthen the candidature of the isolate as a potential probiotic. Further studies revealed B. subtilis AMS6 showed cellulolytic activity (0.54±0.05 filter paper units mL(-1)) at 37°C. The isolate was found to hydrolyze carboxymethyl cellulose, filter paper and maize (Zea mays) straw. The maize straw digestion was confirmed by scanning electron microscopy studies. The isolate was able to degrade filter paper within 96h of incubation. A full length cellulase gene of AMS6 was amplified using degenerate primers consisting of 1499 nucleotides. The ORF encoded for a protein of 499 amino acids residues with a predicted molecular mass of 55.04kDa. The amino acids sequence consisted of a glycosyl hydrolase family 5 domain at N-terminal; Glycosyl hydrolase catalytic core and a CBM-3 cellulose binding domain at its C terminal. The study suggests potential probiotic B. subtilis AMS6 as a promising candidate envisaging its application as an animal feed additive for enhanced fiber digestion and gut health of animal.