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      1. Author :
        Hart, Emily; Azzopardi, Kristy; Taing, Heng; Graichen, Florian; Jeffery, Justine; Mayadunne, Roshan; Wickramaratna, Malsha; O'Shea, Mike; Nijagal, Brunda; Watkinson, Rebecca; O'Leary, Stephen; Finnin, Barrie; Tait, Russell; Robins-Browne, Roy
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        The Journal of antimicrobial chemotherapy
      6. Products :
      7. Volume :
        65
      8. Issue :
        5
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Anti-Bacterial Agents; Bioware; Colony Count, Microbial; Disease Models, Animal; Female; Foreign Bodies; Humans; Mice; Mice, Inbred BALB C; Ofloxacin; Polymers; Prosthesis-Related Infections; Staphylococcal Infections; Staphylococcus aureus; Xen29
      12. Abstract :
        OBJECTIVES To assess support discs, comprising polyethylene terephthalate (PET), coated with different polymer/levofloxacin combinations for antimicrobial activity in an animal model of infection, in order to explore the use of specific polymer coatings incorporating levofloxacin as a means of reducing device-related infections. METHODS Aliphatic polyester-polyurethanes containing different ratios of poly(lactic acid) diol and poly(caprolactone) diol were prepared, blended with levofloxacin and then used to coat support discs. The in vitro levofloxacin release profiles from these discs were measured in aqueous solution. Mice were surgically implanted with the coated discs placed subcutaneously and infection was initiated by injection of 10(6) cfu of Staphylococcus aureus into the subcutaneous pocket containing the implant. After 5, 10, 20 and 30 days, the discs were removed, and the number of bacteria adhering to the implant and the residual antimicrobial activity of the discs were determined. RESULTS In vitro, the release of levofloxacin from the coated discs occurred at a constant rate and then reached a plateau at different timepoints, depending on the polymer preparation used. In vivo, none of the discs coated with polymer blends containing levofloxacin was colonized by S. aureus, whereas 94% of the discs coated with polymer alone were infected. All discs coated with levofloxacin-blended polymers displayed residual antimicrobial activity for at least 20 days post-implantation. CONCLUSIONS Bioerodable polyester-polyurethane polymer coatings containing levofloxacin can prevent bacterial colonization of implants in an intra-operative model of device-related infections.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20233779
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9035
      1. Author :
        Heit, Bryan; Robbins, Stephen M; Downey, Charlene M; Guan, Zhiwen; Colarusso, Pina; Miller, B Joan; Jirik, Frank R; Kubes, Paul
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2008
      5. Publication :
        Nature immunology
      6. Products :
      7. Volume :
        9
      8. Issue :
        7
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Arthritis, Experimental; Bioware; Chemotaxis, Leukocyte; Humans; Inflammation; Mice; Mice, Transgenic; Neutrophils; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phosphatidylinositol Phosphates; Protein Transport; PTEN Phosphohydrolase; Xen29
      12. Abstract :
        Neutrophils encounter and 'prioritize' many chemoattractants in their pursuit of bacteria. Here we tested the possibility that the phosphatase PTEN is responsible for the prioritization of chemoattractants. Neutrophils induced chemotaxis by two separate pathways, the phosphatidylinositol-3-OH kinase (PI(3)K) phosphatase and tensin homolog (PTEN) pathway, and the p38 mitogen-activated protein kinase pathway, with the p38 pathway dominating over the PI(3)K pathway. Pten(-/-) neutrophils could not prioritize chemoattractants and were 'distracted' by chemokines when moving toward bacterial chemoattractants. In opposing gradients, PTEN became distributed throughout the cell circumference, which inhibited all PI(3)K activity, thus permitting 'preferential' migration toward bacterial products via phospholipase A(2) and p38. Such prioritization was defective in Pten(-/-) neutrophils, which resulted in defective bacterial clearance in vivo. Our data identify a PTEN-dependent mechanism in neutrophils to prioritize, 'triage' and integrate responses to multiple chemotactic cues.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/18536720
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9048
      1. Author :
        Kadurugamuwa, Jagath L; Sin, Lin V; Yu, Jun; Francis, Kevin P; Purchio, Tony F; Contag, Pamela R
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2004
      5. Publication :
        Antimicrobial agents and chemotherapy
      6. Products :
      7. Volume :
        48
      8. Issue :
        6
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Antibiotics, Antitubercular; Biofilms; Bioware; Colony Count, Microbial; Diagnostic Imaging; DNA-Directed RNA Polymerases; Luminescent Measurements; Mice; Rifampin; Staphylococcal Infections; Staphylococcus aureus; Xen29
      12. Abstract :
        Eradication of Staphylococcus aureus biofilms after rifampin treatment was tested in a mouse model of device-related infection by using biophotonic imaging. Following treatment, the bioluminescent signals decreased to undetectable levels, irrespective of the age of the biofilm. After the final treatment, the signals rebounded in a time-dependent manner and reached those for the untreated mice. Readministration of rifampin was unsuccessful in eradicating reestablished infections, with the rifampin MICs for such bacteria being increased and with the bacteria having point mutations in the rpoB gene.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/15155235
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9056
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Annals of the New York Academy of Sciences
      6. Products :
      7. Volume :
        1192
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Biofilms; Bioware; Bone Density Conservation Agents; Chronic Disease; Cytokines; Drug Evaluation, Preclinical; Humans; Immunity; Incidence; Jaw Diseases; Mice; Neovascularization, Physiologic; Osteoclasts; Osteomyelitis; Osteonecrosis; Staphylococcal Infections; Xen29
      12. Abstract :
        The effects of antiresorptive agents (e.g., alendronate [Aln], osteoprotegerin [OPG]) on bone infection are unknown. Thus, their effects on implant-associated osteomyelitis (OM) were investigated in mice using PBS (placebo), gentamycin, and etanercept (TNFR:Fc) controls. None of the drugs affected humoral immunity, angiogenesis, or chronic infection. However, the significant (P < 0.05 vs. PBS) inhibition of cortical osteolysis and decreased draining lymph node size in Aln- and OPG-treated mice was associated with a significant (P < 0.05) increase in the incidence of high-grade infections during the establishment of OM. In contrast, the high-grade infections in TNFR:Fc-treated mice were associated with immunosuppression, as evidenced by the absence of granulomas and presence of Gram(+) biofilm in the bone marrow. Collectively, these findings indicate that although antiresorptive agents do not exacerbate chronic OM, they can increase the bacterial load during early infection by decreasing lymphatic drainage and preventing the removal of necrotic bone that harbors the bacteria.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20392222
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9034
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2008
      5. Publication :
        Journal of orthopaedic research: official publication of the Orthopaedic Research Society
      6. Products :
      7. Volume :
        26
      8. Issue :
        1
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Antibody Formation; Bacterial Proteins; Bioware; Disease Models, Animal; DNA, Bacterial; Endonucleases; Female; Mice; Mice, Inbred C57BL; Micrococcal Nuclease; Osteolysis; Osteomyelitis; Prosthesis-Related Infections; Reverse Transcriptase Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus aureus; Tibia; Xen29
      12. Abstract :
        Although osteomyelitis (OM) remains a serious problem in orthopedics, progress has been limited by the absence of an in vivo model that can quantify the bacterial load, metabolic activity of the bacteria over time, immunity, and osteolysis. To overcome these obstacles, we developed a murine model of implant-associated OM in which a stainless steel pin is coated with Staphylococcus aureus and implanted transcortically through the tibial metaphysis. X-ray and micro-CT demonstrated concomitant osteolysis and reactive bone formation, which was evident by day 7. Histology confirmed all the hallmarks of implant-associated OM, namely: osteolysis, sequestrum formation, and involucrum of Gram-positive bacteria inside a biofilm within necrotic bone. Serology revealed that mice mount a protective humoral response that commences with an IgM response after 1 week, and converts to a specific IgG2b response against specific S. aureus proteins by day 11 postinfection. Real-time quantitative PCR (RTQ-PCR) for the S. aureus specific nuc gene determined that the peak bacterial load occurs 11 days postinfection. This coincidence of decreasing bacterial load with the generation of specific antibodies is suggestive of protective humoral immunity. Longitudinal in vivo bioluminescent imaging (BLI) of luxA-E transformed S. aureus (Xen29) combined with nuc RTQ-PCR demonstrated the exponential growth phase of the bacteria immediately following infection that peaks on day 4, and is followed by the biofilm growth phase at a significantly lower metabolic rate (p < 0.05). Collectively, these studies demonstrate the first quantitative model of implant-associated OM that defines the kinetics of microbial growth, osteolysis, and humoral immunity following infection.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/17676625
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9047
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2008
      5. Publication :
        Microbes and infection / Institut Pasteur
      6. Products :
      7. Volume :
        10
      8. Issue :
        3
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Bacterial Proteins; Biofilms; Bioware; Catheterization, Central Venous; Male; Mice; Point Mutation; Sigma Factor; Staphylococcal Infections; Staphylococcus aureus; Virulence; Xen29
      12. Abstract :
        The impact of the alternative sigma factor sigma B (SigB) on pathogenesis of Staphylococcus aureus is not conclusively clarified. In this study, a central venous catheter (CVC) related model of multiorgan infection was used to investigate the role of SigB for the pathogenesis of S. aureus infections and biofilm formation in vivo. Analysis of two SigB-positive wild-type strains and their isogenic mutants revealed uniformly that the wild-type was significantly more virulent than the SigB-deficient mutant. The observed difference in virulence was apparently not linked to the capability of the strains to form biofilms in vivo since wild-type and mutant strains were able to produce biofilm layers inside of the catheter. The data strongly indicate that the alternative sigma factor SigB plays a role in CVC-associated infections caused by S. aureus.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/18328762
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9046
      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
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