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      1. Author :
        Mortin, Lawrence I; Li, Tongchuan; Van Praagh, Andrew D G; Zhang, Shuxin; Zhang, Xi-Xian; Alder, Jeff D
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2007
      5. Publication :
        Antimicrobial agents and chemotherapy
      6. Products :
      7. Volume :
        51
      8. Issue :
        5
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Acetamides; Animals; Anti-Bacterial Agents; Bioware; Colony Count, Microbial; Daptomycin; Female; Luminescent Measurements; Methicillin Resistance; Mice; Microbial Sensitivity Tests; Neutropenia; Oxazolidinones; Peritonitis; Staphylococcus aureus; Xen29
      12. Abstract :
        The rising rates of antibiotic resistance accentuate the critical need for new antibiotics. Daptomycin is a new antibiotic with a unique mode of action and a rapid in vitro bactericidal effect against gram-positive organisms. This study examined the kinetics of daptomycin's bactericidal action against peritonitis caused by methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in healthy and neutropenic mice and compared this activity with those of other commonly used antibiotics. CD-1 mice were inoculated intraperitoneally with lethal doses of MSSA (Xen-29) or MRSA (Xen-1), laboratory strains transformed with a plasmid containing the lux operon, which confers bioluminescence. One hour later, the animals were given a single dose of daptomycin at 50 mg/kg of body weight subcutaneously (s.c.), nafcillin at 100 mg/kg s.c., vancomycin at 100 mg/kg s.c., linezolid at 100 mg/kg via gavage (orally), or saline (10 ml/kg s.c.). The mice were anesthetized hourly, and photon emissions from living bioluminescent bacteria were imaged and quantified. The luminescence in saline-treated control mice either increased (neutropenic mice) or remained relatively unchanged (healthy mice). In contrast, by 2 to 3 h postdosing, daptomycin effected a 90% reduction of luminescence of MSSA or MRSA in both healthy and neutropenic mice. The activity of daptomycin against both MSSA and MRSA strains was superior to those of nafcillin, vancomycin, and linezolid. Against MSSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than nafcillin or linezolid. Against MRSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than vancomycin or linezolid. The rapid decrease in the luminescent signal in the daptomycin-treated neutropenic mice underscores the potency of this antibiotic against S. aureus in the immune-suppressed host.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/17307984
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9050
      1. Author :
        Nejadnik, M Reza; Engelsman, Anton F; Saldarriaga Fernandez, Isabel C; Busscher, Henk J; Norde, Willem; van der Mei, Henny C
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2008
      5. Publication :
        The Journal of antimicrobial chemotherapy
      6. Products :
      7. Volume :
        62
      8. Issue :
        6
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Anti-Bacterial Agents; Bioware; Colony Count, Microbial; Mice; Mice, Inbred BALB C; Polymers; Prostheses and Implants; Rifampin; Silicone Elastomers; Staphylococcus aureus; Vancomycin; Xen29
      12. Abstract :
        OBJECTIVES Curing biomaterial-associated infection (BAI) frequently includes antibiotic treatment, implant removal and re-implantation. However, revision implants are at a greater risk of infection as they may attract bacteria from their infected surroundings. Polymer brush-coatings attract low numbers of bacteria, but the virtue of polymer brush-coatings in vivo has seldom been investigated. Here, we determine the possible benefits of polymer brush-coated versus pristine silicone rubber in revision surgery, using a murine model. METHODS BAI was induced in 26 mice by subcutaneous implantation of silicone rubber discs with a biofilm of Staphylococcus aureus Xen29. During the development of BAI, half of the mice received rifampicin/vancomycin treatment. After 5 days, the infected discs were removed from all mice, and either a polymer brush-coated or pristine silicone rubber disc was re-implanted. Revision discs were explanted after 5 days, and the number of cfu cultured from the discs and the surrounding tissue was determined. RESULTS None of the polymer brush-coated discs after antibiotic treatment appeared colonized by staphylococci, whereas 83% of the pristine silicone rubber discs were re-infected. Polymer brush-coated discs also showed reduced colonization rates in the absence of antibiotic treatment when compared with pristine silicone rubber discs. Tissue surrounding the discs was culture-positive in all cases. CONCLUSIONS Polymer brush-coatings are less prone to re-infection than pristine silicone rubber when used in revision surgery, i.e. when implanted in a subcutaneous pocket infected by a staphylococcal BAI. Antibiotic pre-treatment during the development of BAI hardly had any effect in preventing the colonization of pristine silicone rubber.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/18812426
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9045
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Journal of immunology (Baltimore, Md.: 1950)
      6. Products :
      7. Volume :
        184
      8. Issue :
        5
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides; Bacterial Infections; Bioware; Cell Line; Cells, Cultured; Chemokine CCL2; Chemokine CCL7; Chemokine CXCL1; Chemokines; Female; Humans; Interleukin-8; Leukocytes; Leukocytes, Mononuclear; Macrophages; Mice; Mice, Inbred C57BL; Molecular Sequence Data; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phosphorylation; Staphylococcal Infections; Staphylococcus aureus; Xen29, Xen14
      12. Abstract :
        With the rapid rise in the incidence of multidrug resistant infections, there is substantial interest in host defense peptides as templates for production of new antimicrobial therapeutics. Natural peptides are multifunctional mediators of the innate immune response, with some direct antimicrobial activity and diverse immunomodulatory properties. We have previously developed an innate defense regulator (IDR) 1, with protective activity against bacterial infection mediated entirely through its effects on the immunity of the host, as a novel approach to anti-infective therapy. In this study, an immunomodulatory peptide IDR-1002 was selected from a library of bactenecin derivatives based on its substantially more potent ability to induce chemokines in human PBMCs. The enhanced chemokine induction activity of the peptide in vitro correlated with stronger protective activity in vivo in the Staphylococcus aureus-invasive infection model, with a >5-fold reduction in the protective dose in direct comparison with IDR-1. IDR-1002 also afforded protection against the Gram-negative bacterial pathogen Escherichia coli. Chemokine induction by IDR-1002 was found to be mediated through a Gi-coupled receptor and the PI3K, NF-kappaB, and MAPK signaling pathways. The protective activity of the peptide was associated with in vivo augmentation of chemokine production and recruitment of neutrophils and monocytes to the site of infection. These results highlight the importance of the chemokine induction activity of host defense peptides and demonstrate that the optimization of the ex vivo chemokine-induction properties of peptides is a promising method for the rational development of immunomodulatory IDR peptides with enhanced anti-infective activity.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20107187
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9033
      1. Author :
        Ohlsen, Knut; Lorenz, Udo
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2007
      5. Publication :
        Future microbiology
      6. Products :
      7. Volume :
        2
      8. Issue :
        6
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Anti-Bacterial Agents; Bioware; Community-Acquired Infections; Humans; Methicillin Resistance; Staphylococcal Infections; Staphylococcus aureus; Xen29
      12. Abstract :
        Multiple resistant staphylococci that cause significant morbidity and mortality are the leading cause of nosocomial infections. Meanwhile, methicillin-resistant Staphylococcus aureus (MRSA) also spreads in the community, where highly virulent strains infect children and young adults who have no predisposing risk factors. Although some treatment options remain, the search for new antibacterial targets and lead compounds is urgently required to ensure that staphylococcal infections can be effectively treated in the future. Promising targets for new antibacterials are gene products that are involved in essential cell functions. In addition to antibacterials, active and passive immunization strategies are being developed that target surface components of staphylococci such as cell wall-linked adhesins, teichoic acids and capsule or immunodominant antigens.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/18041906
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9049
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Acta biomaterialia
      6. Products :
      7. Volume :
        6
      8. Issue :
        3
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Bacterial Adhesion; Biocompatible Materials; Biofilms; Bioware; Coated Materials, Biocompatible; Materials Testing; Polyethylene Glycols; Staphylococcus aureus; Staphylococcus epidermidis; Surface Properties; Xen29
      12. Abstract :
        Poly(ethylene glycol) (PEG) coatings are known to reduce microbial adhesion in terms of numbers and binding strength. However, bacterial adhesion remains of the order of 10(4)cm(-2). It is unknown whether this density of bacteria will eventually grow into a biofilm. This study investigates the kinetics of staphylococcal biofilm formation on a commercially produced, robust, cross-linked PEG-based polymer coating (OptiChem) in vitro and in vivo. OptiChem inhibits biofilm formation in vitro, and although adsorption of plasma proteins encourages biofilm formation, microbial growth kinetics are still strongly delayed compared to uncoated glass. In vivo, OptiChem-coated and bare silicone rubber samples were inserted into an infected murine subcutaneous pocket model. In contrast to bare silicone rubber, OptiChem samples did not become colonized upon reimplantation despite the fact that surrounding tissues were always culture-positive. We conclude that the commercial OptiChem coating considerably slows down bacterial biofilm formation both in vitro and in vivo, making it an attractive candidate for biomaterials implant coating.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19733265
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9041
      1. Author :
        Sjollema, Jelmer; Sharma, Prashant K; Dijkstra, Rene J B; van Dam, Gooitzen M; van der Mei, Henny C; Engelsman, Anton F; Busscher, Henk J
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Biomaterials
      6. Products :
      7. Volume :
        31
      8. Issue :
        8
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Anti-Infective Agents; Bacteria; Bacterial Infections; Biocompatible Materials; Biofilms; Bioware; Coated Materials, Biocompatible; Fluorescent Dyes; Humans; Image Enhancement; Light; Luminescent Measurements; Luminescent Proteins; Microscopy, Fluorescence; Prosthesis-Related Infections; Sensitivity and Specificity; Xen29
      12. Abstract :
        This review presents the current state of Bioluminescence and Fluorescent Imaging technologies (BLI and FLI) as applied to Biomaterial-Associated Infections (BAI). BLI offers the opportunity to observe the in vivo course of BAI in small animals without the need to sacrifice animals at different time points after the onset of infection. BLI is highly dependent on the bacterial cell metabolism which makes BLI a strong reporter of viable bacterial presence. Fluorescent sources are generally more stable than bioluminescent ones and specifically targeted, which renders the combination of BLI and FLI a promising tool for imaging BAI. The sensitivity and spatial resolution of both imaging tools are, however, dependent on the imaging system used and the tissue characteristics, which makes the interpretation of images, in terms of the location and shape of the illuminating source, difficult. Tomographic reconstruction of the luminescent source is possible in the most modern instruments, enabling exact localization of a colonized implant material, spreading of infecting organisms in surrounding tissue and immunological tissue reactions. BLI studies on BAI have successfully distinguished between different biomaterials with respect to the development and clearance of BAI in vivo, simultaneously reducing animal use and experimental variation. It is anticipated that bio-optical imaging will become an indispensable technology for the in vivo evaluation of antimicrobial coatings.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19969345
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9038
      1. Author :
        Yu, Jun; Wu, Jenny; Francis, Kevin P; Purchio, Tony F; Kadurugamuwa, Jagath L
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2005
      5. Publication :
        The Journal of antimicrobial chemotherapy
      6. Products :
      7. Volume :
        55
      8. Issue :
        4
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Anti-Bacterial Agents; Biofilms; Bioware; Drug Resistance, Bacterial; Mice; Mutation; Rifampin; Staphylococcus aureus; Xen29
      12. Abstract :
        OBJECTIVES To investigate in vivo fitness of rifampicin-resistant Staphylococcus aureus mutants in a mouse biofilm model using bioluminescence imaging. MATERIALS AND METHODS S. aureus was engineered with a luciferase operon to emit bioluminescence that can be detected in vivo using an IVIS imaging system. Two rifampicin-resistant strains of S. aureus that were previously isolated from animals undergoing rifampicin treatment, S464P (resistant to low concentrations of rifampicin) and H481Y (resistant to high concentrations of rifampicin), were characterized and then compared with their parental strain for in vivo fitness to form biofilm infections in the absence of rifampicin. RESULTS The mutant S464P showed better adaptation to in vivo growth than either the parental strain or H481Y without selective pressure. Six days after implanting pre-colonized catheters, bioluminescent signals were seen from 100% of the catheters coated by the mutant S464P. In comparison, only 83% and 61% of the catheters coated by the parental strain and H481Y, respectively, maintained a signal in vivo. Rifampicin treatment of S464P biofilms in vivo resulted in a slight decline, but earlier rebound in bioluminescence from these catheters compared with the parental signal, whereas rifampicin had no affect on bioluminescence in mice infected with mutant H481Y. CONCLUSIONS The mutant with low-level rifampicin resistance appears to be better adapted to in vivo growth than the mutant that has high-level rifampicin resistance. Moreover, the former mutant may actually have a slight competitive advantage over the rifampicin-susceptible strain (parental), raising awareness for the occurrence of such strains in clinical environments.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/15743898
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9055
      1. Author :
        Ketonis, Constantinos; Barr, Stephanie; Adams, Christopher S; Hickok, Noreen J; Parvizi, Javad
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Clinical orthopaedics and related research
      6. Products :
      7. Volume :
        468
      8. Issue :
        8
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Anti-Bacterial Agents; Biofilms; Bioware; Bone Substitutes; Bone Transplantation; Prostheses and Implants; Prosthesis-Related Infections; Staphylococcal Infections; Staphylococcus aureus; Transplantation, Homologous; Vancomycin; Xen36
      12. Abstract :
        BACKGROUND Bone grafts are frequently used to supplement bone stock and to establish structural stability. However, graft-associated infection represents a challenging complication leading to increased patient morbidity and healthcare costs. QUESTIONS/PURPOSES We therefore designed this study to (1) determine if increasing initial S. aureus inoculation of bone allograft results in a proportionate increase in colonization; (2) assess if antibiotics decrease colonization and if antibiotic tethering to allograft alters its ability to prevent bacterial colonization; and (3) determine if covalent modification alters the allograft topography or its biological properties. METHODS Allograft bone and vancomycin-modified bone (VAN-bone) was challenged with different doses of S. aureus for times out to 24 hours in the presence or absence of solution vancomycin. Bacterial colonization was assessed by fluorescence, scanning electron microscopy (SEM), and by direct colony counting. Cell density and distribution of osteoblast-like cells on control and modified allograft were then compared. RESULTS Bacterial attachment was apparent within 6 hours with colonization and biofilm formation increasing with time and dose. Solution vancomycin failed to prevent bacterial attachment whereas VAN-bone successfully resisted colonization. The allograft modification did not affect the attachment and distribution of osteoblast-like cells. CONCLUSIONS Allograft bone was readily colonized by S. aureus and covered by a biofilm with especially florid growth in natural topographic niches. Using a novel covalent modification, allograft bone was able to resist colonization by organisms while retaining the ability to allow adhesion of osteoblastic cells. CLINICAL RELEVANCE Generation of allograft bone that can resist infection in vivo would be important in addressing one of the most challenging problems associated with the use of allograft, namely infection.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20361282
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9981
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2007
      5. Publication :
        Journal of immunology (Baltimore, Md.: 1950)
      6. Products :
      7. Volume :
        179
      8. Issue :
        9
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Amine Oxidase (Copper-Containing); Animals; Bacterial Adhesion; Bioware; Cell Adhesion Molecules; Coxsackievirus Infections; Immunity, Mucosal; Immunoglobulin A; Lymphocyte Count; Lymphocytes; Lymphoid Tissue; Mice; Mice, Inbred C57BL; Mice, Knockout; Peyer's Patches; Receptors, Lymphocyte Homing; Staphylococcal Vaccines; Staphylococcus aureus; Xen36
      12. Abstract :
        VAP-1, an ecto-enzyme expressed on the surface of endothelial cells, is involved in leukocyte trafficking between the blood and tissues under physiological and pathological conditions. In this study, we used VAP-1-deficient mice to elucidate whether absence of VAP-1 alters the immune system under normal conditions and upon immunization and microbial challenge. We found that VAP-1-deficient mice display age-dependent paucity of lymphocytes, in the Peyer's patches of the gut. IgA concentration in serum was also found to be lower in VAP-1(-/-) animals than in wild-type mice. Although there were slightly less CD11a on B and T cells isolated from VAP-1-deficient mice than on those from wild-type mice, there were no differences in the expression of gut-homing-associated adhesion molecules or chemokine receptors. Because anti-VAP-1 therapies are being developed for clinical use to treat inflammation, we determined the effect of VAP-1 deletion on useful immune responses. Oral immunization with OVA showed defective T and B cell responses in VAP-1-deficient mice. Antimicrobial immune responses against Staphylococcus aureus and coxsackie B4 virus were also affected by the absence of VAP-1. Importantly, when the function of VAP-1 was acutely neutralized using small molecule enzyme inhibitors and anti-VAP-1 Abs rather than by gene deletion, no significant impairment in antimicrobial control was detected. In conclusion, VAP-1-deficient mice have mild deviations in the mucosal immune system and therapeutic targeting of VAP-1 does not appear to cause a generalized increase in the risk of infection.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/17947691
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9984
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