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      1. Author :
        Bendaoud, M.; Vinogradov, E.; Balashova, N. V.; Kadouri, D. E.; Kachlany, S. C.; Kaplan, J. B.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        J Bacteriol
      6. Products :
      7. Volume :
        193
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Xen29, Xen 29, Staphylococcus aureus Xen29, IVISBacterial Physiological Phenomena/drug effects; Bacterial Proteins/genetics/metabolism; Biofilms/*drug effects; *Down-Regulation/drug effects; Fungi/drug effects/physiology; Kingella kingae/chemistry/genetics/*metabolism; Molecular Sequence Data; Polysaccharides, Bacterial/biosynthesis/chemistry/*pharmacology
      12. Abstract :
        Cell-free extracts prepared from Kingella kingae colony biofilms were found to inhibit biofilm formation by Aggregatibacter actinomycetemcomitans, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Candida albicans, and K. kingae. The extracts evidently inhibited biofilm formation by modifying the physicochemical properties of the cell surface, the biofilm matrix, and the substrate. Chemical and biochemical analyses indicated that the biofilm inhibition activity in the K. kingae extract was due to polysaccharide. Structural analyses showed that the extract contained two major polysaccharides. One was a linear polysaccharide with the structure -->6)-alpha-d-GlcNAcp-(1-->5)-beta-d-OclAp-(2-->, which was identical to a capsular polysaccharide produced by Actinobacillus pleuropneumoniae serotype 5. The second was a novel linear polysaccharide, designated PAM galactan, with the structure -->3)-beta-d-Galf-(1-->6)-beta-d-Galf-(1-->. Purified PAM galactan exhibited broad-spectrum biofilm inhibition activity. A cluster of three K. kingae genes encoding UDP-galactopyranose mutase (ugm) and two putative galactofuranosyl transferases was sufficient for the synthesis of PAM galactan in Escherichia coli. PAM galactan is one of a growing number of bacterial polysaccharides that exhibit antibiofilm activity. The biological roles and potential technological applications of these molecules remain unknown.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/21602333
      14. Call Number :
        PKI @ kd.modi @ 17
      15. Serial :
        10446
      1. Author :
        Bernthal, N. M.; Stavrakis, A. I.; Billi, F.; Cho, J. S.; Kremen, T. J.; Simon, S. I.; Cheung, A. L.; Finerman, G. A.; Lieberman, J. R.; Adams, J. S.; Miller, L. S.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        PLoS One
      6. Products :
      7. Volume :
        5
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Animals; Anti-Bacterial Agents/*therapeutic use; Arthroplasty/*adverse effects; Disease Models, Animal; Humans; Joint Diseases/drug therapy/*microbiology/surgery; Joints/microbiology/surgery; Male; Mice; Mice, Inbred C57BL; Minocycline/therapeutic use; Postoperative Complications/drug therapy/microbiology/*prevention &; control; Prostheses and Implants; Rifampin/therapeutic use; Staphylococcal Infections/drug therapy/microbiology/*prevention &; control/surgery; Staphylococcus aureus/drug effects/genetics/*physiology
      12. Abstract :
        BACKGROUND: Post-arthroplasty infections represent a devastating complication of total joint replacement surgery, resulting in multiple reoperations, prolonged antibiotic use, extended disability and worse clinical outcomes. As the number of arthroplasties in the U.S. will exceed 3.8 million surgeries per year by 2030, the number of post-arthroplasty infections is projected to increase to over 266,000 infections annually. The treatment of these infections will exhaust healthcare resources and dramatically increase medical costs. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate novel preventative therapeutic strategies against post-arthroplasty infections, a mouse model was developed in which a bioluminescent Staphylococcus aureus strain was inoculated into a knee joint containing an orthopaedic implant and advanced in vivo imaging was used to measure the bacterial burden in real-time. Mice inoculated with 5x10(3) and 5x10(4) CFUs developed increased bacterial counts with marked swelling of the affected leg, consistent with an acute joint infection. In contrast, mice inoculated with 5x10(2) CFUs developed a low-grade infection, resembling a more chronic infection. Ex vivo bacterial counts highly correlated with in vivo bioluminescence signals and EGFP-neutrophil fluorescence of LysEGFP mice was used to measure the infection-induced inflammation. Furthermore, biofilm formation on the implants was visualized at 7 and 14 postoperative days by variable-pressure scanning electron microscopy (VP-SEM). Using this model, a minocycline/rifampin-impregnated bioresorbable polymer implant coating was effective in reducing the infection, decreasing inflammation and preventing biofilm formation. CONCLUSIONS/SIGNIFICANCE: Taken together, this mouse model may represent an alternative pre-clinical screening tool to evaluate novel in vivo therapeutic strategies before studies in larger animals and in human subjects. Furthermore, the antibiotic-polymer implant coating evaluated in this study was clinically effective, suggesting the potential for this strategy as a therapeutic intervention to combat post-arthroplasty infections.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20830204
      14. Call Number :
        PKI @ kd.modi @ 5
      15. Serial :
        10447
      1. Author :
        Jadert, C.; Petersson, J.; Massena, S.; Ahl, D.; Grapensparr, L.; Holm, L.; Lundberg, J. O.; Phillipson, M.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        Free Radic Biol Med
      6. Products :
      7. Volume :
        N/A
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29
      12. Abstract :
        Nitric oxide (NO) generated by vascular NO synthases can exert anti-inflammatory effects, partly through its ability to decrease leukocyte recruitment. Inorganic nitrate and nitrite, from endogenous or dietary sources, have emerged as alternative substrates for NO formation in mammals. Bioactivation of nitrate is believed to require initial reduction to nitrite by oral commensal bacteria. Here we investigated the effects of inorganic nitrate and nitrite on leukocyte recruitment in microvascular inflammation and in NSAID-induced small-intestinal injury. We show that leukocyte emigration in response to the proinflammatory chemokine MIP-2 is reduced by 70% after 7days of dietary nitrate supplementation as well as by acute intravenous nitrite administration. Nitrite also reduced leukocyte adhesion to a similar extent and this effect was inhibited by the soluble guanylyl cyclase inhibitor ODQ, whereas the effect on emigrated leukocytes was not altered by this treatment. Further studies in TNF-alpha-stimulated endothelial cells revealed that nitrite dose-dependently reduced the expression of ICAM-1. In rats and mice subjected to a challenge with diclofenac, dietary nitrate prevented the increase in myeloperoxidase and P-selectin levels in small-intestinal tissue. Antiseptic mouthwash, which eliminates oral nitrate reduction, markedly blunted the protective effect of dietary nitrate on P-selectin levels. Despite attenuation of the acute immune response, the overall ability to clear an infection with Staphylococcus aureus was not suppressed by dietary nitrate as revealed by noninvasive IVIS imaging. We conclude that dietary nitrate markedly reduces leukocyte recruitment to inflammation in a process involving attenuation of P-selectin and ICAM-1 upregulation. Bioactivation of dietary nitrate requires intermediate formation of nitrite by oral nitrate-reducing bacteria and then probably further reduction to NO and other bioactive nitrogen oxides in the tissues.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/22178413
      14. Call Number :
        PKI @ kd.modi @ 18
      15. Serial :
        10452
      1. Author :
        Hasenpusch, G.; Pfeifer, C.; Aneja, M. K.; Wagner, K.; Reinhardt, D.; Gilon, M.; Ohana, P.; Hochberg, A.; Rudolph, C.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        PLoS One
      6. Products :
      7. Volume :
        6
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Administration, Inhalation; Aerosols; Animals; Cell Line, Tumor; Cell Proliferation/drug effects; Cell Transformation, Neoplastic; Humans; Lung Neoplasms/drug therapy/genetics/*pathology/*secondary; Mice; Oncogenes/genetics; Plasmids/*administration & dosage/chemistry/*pharmacology; Polyethyleneimine/chemistry
      12. Abstract :
        Despite numerous efforts, drug based treatments for patients suffering from lung cancer remains poor. As a promising alternative, we investigated the therapeutic potential of BC-819 for the treatment of lung cancer in mouse tumor models. BC-819 is a novel plasmid DNA which encodes for the A-fragment of Diphtheria toxin and has previously been shown to successfully inhibit tumor growth in human clinical study of bladder carcinoma. In a first set of experiments, we examined in vitro efficacy of BC-819 in human lung cancer cell-lines NCI-H460, NCI-H358 and A549, which revealed >90% reduction of cell growth. In vivo efficacy was examined in an orthotopic mouse xenograft lung cancer model and in a lung metastasis model using luminescent A549-C8-luc adenocarcinoma cells. These cells resulted in peri- and intra-bronchiolar tumors upon intrabronchial application and parenchymal tumors upon intravenous injection, respectively. Mice suffering from these lung tumors were treated with BC-819, complexed to branched polyethylenimine (PEI) and aerosolized to the mice once per week for a period of 10 weeks. Using this regimen, growth of intrabronchially induced lung tumors was significantly inhibited (p = 0.01), whereas no effect could be observed in mice suffering from lung metastasis. In summary, we suggest that aerosolized PEI/BC-819 is capable of reducing growth only in tumors arising from the luminal part of the airways and are therefore directly accessible for inhaled BC-819.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/21687669
      14. Call Number :
        PKI @ kd.modi @ 9
      15. Serial :
        10450
      1. Author :
        Hertlein, T.; Sturm, V.; Kircher, S.; Basse-Lusebrink, T.; Haddad, D.; Ohlsen, K.; Jakob, P.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        PLoS One
      6. Products :
      7. Volume :
        6
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Animals; Female; Magnetic Resonance Imaging/*methods; Mice; Mice, Inbred BALB C; Staphylococcal Infections/*pathology; Staphylococcus aureus/*pathogenicity; Thigh/*microbiology/*pathology
      12. Abstract :
        BACKGROUND: During the last years, (19)F-MRI and perfluorocarbon nanoemulsion (PFC) emerged as a powerful contrast agent based MRI methodology to track cells and to visualize inflammation. We applied this new modality to visualize deep tissue abscesses during acute and chronic phase of inflammation caused by Staphylococcus aureus infection. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, a murine thigh infection model was used to induce abscess formation and PFC or CLIO (cross linked ironoxides) was administered during acute or chronic phase of inflammation. 24 h after inoculation, the contrast agent accumulation was imaged at the site of infection by MRI. Measurements revealed a strong accumulation of PFC at the abscess rim at acute and chronic phase of infection. The pattern was similar to CLIO accumulation at chronic phase and formed a hollow sphere around the edema area. Histology revealed strong influx of neutrophils at the site of infection and to a smaller extend macrophages during acute phase and strong influx of macrophages at chronic phase of inflammation. CONCLUSION AND SIGNIFICANCE: We introduce (19)F-MRI in combination with PFC nanoemulsions as a new platform to visualize abscess formation in a murine thigh infection model of S. aureus. The possibility to track immune cells in vivo by this modality offers new opportunities to investigate host immune response, the efficacy of antibacterial therapies and the influence of virulence factors for pathogenesis.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/21455319
      14. Call Number :
        PKI @ kd.modi @ 2
      15. Serial :
        10451
      1. Author :
        Lorenz, U.; Schafer, T.; Ohlsen, K.; Tiurbe, G. C.; Buhler, C.; Germer, C. T.; Kellersmann, R.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        Eur J Vasc Endovasc Surg
      6. Products :
      7. Volume :
        41
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Acetates; Animals; *Biofilms; Bioprosthesis; Blood Vessel Prosthesis/*microbiology; Cattle; Colony Count, Microbial; Luminescent Measurements/*methods; Mice; Microbial Viability; Pericardium; *Photons; Polyesters; Polytetrafluoroethylene; Prospective Studies; Prosthesis-Related Infections/*diagnosis; Random Allocation; Silver Compounds; Staphylococcus aureus/isolation & purification/*physiology
      12. Abstract :
        OBJECTIVES: Biophotonic imaging was compared to standard enumeration method both for counting Staphylococcus aureus in biofilm and bacterial susceptibility tests of different graft materials. DESIGN: Prospective, randomized, controlled animal study. MATERIAL AND METHODS: Five types of vascular grafts were placed subcutaneously in 35 mice and challenged with bioluminescent S. aureus. The mice were divided into equal groups as follows: group A (polyester), group B (polytetrafluoroethylene), group C and D (two types of silver acetate-coated polyester) and group E (bovine pericardium). Controls were given only the bacteria. The bioluminescence signal of S. aureus, able to predict number of viable bacteria in biofilm without any manipulation, was measured at different time points. Five days postinfection, regular cultures of adherent bacteria on grafts were obtained. Comparative analyses between bioluminescence activity and culture enumeration were performed. RESULTS: The number of viable bacteria on silver-coated prostheses was the slightest, indicating superior bacterial resistance. The density of bacteria on polytetrafluoroethylene and polyester was comparable, with a non-significant advantage for polytetrafluoroethylene. Moreover, bioluminescence detected the number of viable S. aureus in biofilm more exactly compared to enumeration of bacteria. CONCLUSION: Bioluminescence imaging can be considered a useful tool to characterize susceptibility of any graft material to bacterial biofilm prior to implantation.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20943422
      14. Call Number :
        PKI @ kd.modi @ 12
      15. Serial :
        10453
      1. Author :
        Panizzi, P.; Nahrendorf, M.; Figueiredo, J. L.; Panizzi, J.; Marinelli, B.; Iwamoto, Y.; Keliher, E.; Maddur, A. A.; Waterman, P.; Kroh, H. K.; Leuschner, F.; Aikawa, E.; Swirski, F. K.; Pittet, M. J.; Hackeng, T. M.; Fuentes-Prior, P.; Schneewind, O.; Bock, P. E.; Weissleder, R.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        Nat Med
      6. Products :
      7. Volume :
        17
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Animals; Coagulase/metabolism; Endocarditis, Bacterial/*diagnosis; Mice; Microscopy, Fluorescence; Positron-Emission Tomography; Protein Engineering; Prothrombin/*diagnostic use/*metabolism; Quorum Sensing/physiology; Staphylococcus aureus/*metabolism/pathogenicity
      12. Abstract :
        Coagulase-positive Staphylococcus aureus (S. aureus) is the major causal pathogen of acute endocarditis, a rapidly progressing, destructive infection of the heart valves. Bacterial colonization occurs at sites of endothelial damage, where, together with fibrin and platelets, the bacteria initiate the formation of abnormal growths known as vegetations. Here we report that an engineered analog of prothrombin could be used to detect S. aureus in endocarditic vegetations via noninvasive fluorescence or positron emission tomography (PET) imaging. These prothrombin derivatives bound staphylocoagulase and intercalated into growing bacterial vegetations. We also present evidence for bacterial quorum sensing in the regulation of staphylocoagulase expression by S. aureus. Staphylocoagulase expression was limited to the growing edge of mature vegetations, where it was exposed to the host and co-localized with the imaging probe. When endocarditis was induced with an S. aureus strain with genetic deletion of coagulases, survival of mice improved, highlighting the role of staphylocoagulase as a virulence factor.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/21857652
      14. Call Number :
        PKI @ kd.modi @ 16
      15. Serial :
        10454
      1. Author :
        Pettersson, U. S.; Christoffersson, G.; Massena, S.; Ahl, D.; Jansson, L.; Henriksnas, J.; Phillipson, M.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2011
      5. Publication :
        PLoS One
      6. Products :
      7. Volume :
        6
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xen29, Xen 29, Staphylococcus aureus Xen29, Animals; Blood Glucose/metabolism; Cell Adhesion/drug effects; Cell Count; Cell Movement/drug effects; Chemokine CXCL2/pharmacology; Diabetes Mellitus, Type 1/blood/complications/*immunology/microbiology; Diabetes Mellitus, Type 2/blood/complications/*immunology/microbiology; Diet, High-Fat/adverse effects; Disease Models, Animal; Hyperglycemia/chemically induced/complications; Inflammation/blood/complications/immunology/microbiology; Leukocytes/cytology/drug effects/*immunology/microbiology; Male; Mice; Mice, Inbred C57BL; Phagocytes/cytology/drug effects/microbiology; Staphylococcus aureus/physiology
      12. Abstract :
        BACKGROUND: Patients suffering from diabetes show defective bacterial clearance. This study investigates the effects of elevated plasma glucose levels during diabetes on leukocyte recruitment and function in established models of inflammation. METHODOLOGY/PRINCIPAL FINDINGS: Diabetes was induced in C57Bl/6 mice by intravenous alloxan (causing severe hyperglycemia), or by high fat diet (moderate hyperglycemia). Leukocyte recruitment was studied in anaesthetized mice using intravital microscopy of exposed cremaster muscles, where numbers of rolling, adherent and emigrated leukocytes were quantified before and during exposure to the inflammatory chemokine MIP-2 (0.5 nM). During basal conditions, prior to addition of chemokine, the adherent and emigrated leukocytes were increased in both alloxan- (62+/-18% and 85+/-21%, respectively) and high fat diet-induced (77+/-25% and 86+/-17%, respectively) diabetes compared to control mice. MIP-2 induced leukocyte emigration in all groups, albeit significantly more cells emigrated in alloxan-treated mice (15.3+/-1.0) compared to control (8.0+/-1.1) mice. Bacterial clearance was followed for 10 days after subcutaneous injection of bioluminescent S. aureus using non-invasive IVIS imaging, and the inflammatory response was assessed by Myeloperoxidase-ELISA and confocal imaging. The phagocytic ability of leukocytes was assessed using LPS-coated fluorescent beads and flow cytometry. Despite efficient leukocyte recruitment, alloxan-treated mice demonstrated an impaired ability to clear bacterial infection, which we found correlated to a 50% decreased phagocytic ability of leukocytes in diabetic mice. CONCLUSIONS/SIGNIFICANCE: These results indicate that reduced ability to clear bacterial infections observed during experimentally induced diabetes is not due to reduced leukocyte recruitment since sustained hyperglycemia results in increased levels of adherent and emigrated leukocytes in mouse models of type 1 and type 2 diabetes. Instead, decreased phagocytic ability observed for leukocytes isolated from diabetic mice might account for the impaired bacterial clearance.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/21799868
      14. Call Number :
        PKI @ kd.modi @ 20
      15. Serial :
        10455