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      1. Author :
        Hardy, Jonathan; Chu, Pauline; Contag, Christopher H
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Disease models & mechanisms
      6. Products :
      7. Volume :
        2
      8. Issue :
        1-2
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Bioware; Bone Marrow; Bone Marrow Cells; Disease Models, Animal; Female; Host-Pathogen Interactions; Humans; Knee Joint; Listeria monocytogenes; Listeriosis; Mice; Mice, Inbred BALB C; Mutation; pXen-5; Tibia
      12. Abstract :
        Murine listeriosis is one of the most comprehensive and well-studied models of infection, and Listeria monocytogenes has provided seminal information regarding bacterial pathogenesis. However, many aspects of the mouse model remain poorly understood, including carrier states and chronic colonization which represent important features of the spectrum of host-pathogen interaction. Bone marrow has recently been shown to harbor L. monocytogenes, which spreads from this location to the central nervous system. Bone could, therefore, be an important chronic reservoir, but this infection is difficult to study because it involves only a few bacteria and the extent of infection cannot be assessed until after the animal is sacrificed. We employed in vivo bioluminescence imaging to localize L. monocytogenes bone infections over time in live mice, revealing that the bacteria grow in discrete foci. These lesions can persist in many locations in the legs of mice and are not accompanied by a histological indication such as granuloma or a neutrophil infiltratate. We demonstrate that highly attenuated hly mutants, which have defective intracellular replication, are capable of prolonged focal infection of the bone marrow for periods of up to several weeks. These results support the recently proposed hypothesis that the bone marrow is a unique niche for L. monocytogenes.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19132117
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9018
      1. Author :
        Harms, Jerome S; Durward, Marina A; Magnani, Diogo M; Splitter, Gary A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Journal of immune based therapies and vaccines
      6. Products :
      7. Volume :
        7
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Bioware; pXen-13
      12. Abstract :
        BACKGROUND There is no safe, effective human vaccine against brucellosis. Live attenuated Brucella strains are widely used to vaccinate animals. However these live Brucella vaccines can cause disease and are unsafe for humans. Killed Brucella or subunit vaccines are not effective in eliciting long term protection. In this study, we evaluate an approach using a live, non-pathogenic bacteria (E. coli) genetically engineered to mimic the brucellae pathway of infection and present antigens for an appropriate cytolitic T cell response. METHODS E. coli was modified to express invasin of Yersinia and listerialysin O (LLO) of Listeria to impart the necessary infectivity and antigen releasing traits of the intracellular pathogen, Brucella. This modified E. coli was considered our vaccine delivery system and was engineered to express Green Fluorescent Protein (GFP) or Brucella antigens for in vitro and in vivo immunological studies including cytokine profiling and cytotoxicity assays. RESULTS The E. coli vaccine vector was able to infect all cells tested and efficiently deliver therapeutics to the host cell. Using GFP as antigen, we demonstrate that the E. coli vaccine vector elicits a Th1 cytokine profile in both primary and secondary immune responses. Additionally, using this vector to deliver a Brucella antigen, we demonstrate the ability of the E. coli vaccine vector to induce specific Cytotoxic T Lymphocytes (CTLs). CONCLUSION Protection against most intracellular bacterial pathogens can be obtained mostly through cell mediated immunity. Data presented here suggest modified E. coli can be used as a vaccine vector for delivery of antigens and therapeutics mimicking the infection of the pathogen and inducing cell mediated immunity to that pathogen.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19126207
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9029
      1. Author :
        Engelsman, A. F.; Mei, H. C. van der; Francis, K. P.; Busscher, H. J.; Ploeg, R. J.; Dam, G. M. van
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        J Biomed Mater Res B Appl Biomater
      6. Products :
      7. Volume :
        88
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Bioware; IVIS, Xenogen; Xen29
      12. Abstract :
        Infection is the main cause of biomaterials-related failure. A simple technique to test in-vivo new antimicrobial and/or nonadhesive implant coatings is unavailable. Current in vitro methods for studying bacterial adhesion and growth on biomaterial surfaces lack the influence of the host immune system. Most in vivo methods to study biomaterials-related infections routinely involve implant-removal, preventing comprehensive longitudinal monitoring. In vivo imaging circumvents these drawbacks and is based on the use of noninvasive optical imaging of bioluminescent bacteria. Staphylococcus aureus Xen29 is genetically modified to be stably bioluminescent, by the introduction of a modified full lux operon onto its chromosome. Surgical meshes with adhering S. aureus Xen29 were implanted in mice and bacterial growth and spread into the surrounding tissue was monitored longitudinally from bioluminescence with a highly sensitive CCD camera. Distinct spatiotemporal bioluminescence patterns, extending beyond the mesh area into surrounding tissues were observed. After 10 days, the number of living organisms isolated from explanted meshes was found to correlate with bioluminescence prior to sacrifice of the animals. Therefore, it is concluded that in vivo imaging using bioluminescent bacteria is ideally suited to study antimicrobial coatings taking into account the host immune system. In addition, longitudinal monitoring of infection in one animal will significantly reduce the number of experiments and animals.
      13. URL :
        http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18618733
      14. Call Number :
        137698
      15. Serial :
        7462
      1. Author :
        De Kwaadsteniet, Michele
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        N/A
      6. Products :
      7. Volume :
        N/A
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Antibiotics -- Therapeutic use; Bacteriocins; Bioware; Dissertations -- Microbiology; Drug resistance in microorganisms; Nisin; Respiratory infections -- Treatment; Skin -- Infections -- Treatment; Staphylococcus aureus; Theses -- Microbiology; Xen29
      12. Abstract :
        Multidrug resistant strains of Staphylococcus aureus is presenting an increasing threat, especially immune compromised individuals. Many of these strains have developed resistance to newly approved drugs such as quinupristin-dalfopristin, linezolid and daptomycin. The search for alternative treatment, including bacteriocins (ribosomally synthesized antimicrobial peptides) of lactic acid bacteria is increasing . Lactococcus lactis subsp. lactis F10, isolated from freshwater catfish, produced a new nisin variant active against clinical strains of S. aureus. The operon encoding nisin F is located on a plasmid and the structural gene has been sequenced. The lantibiotic is closely related to nisin Z, except at position 30 where valine replaced isoleucine. The antimicrobial activity of nisin F against S. aureus was tested in the respiratory tract of Wistar rats. Non-immunosuppressed and immunosuppressed rats were intranasally infected with S. aureus K and then treated with either nisin F or sterile physiological saline. Nisin F protected immunosuppressed rats against S. aureus, as symptoms of an infection were only detected in the trachea and lungs of immunosuppressed rats treated with saline. The safety of intranasally administered nisin F was also evaluated and proved to have no adverse side effects. The potential of nisin F as an antimicrobial agent to treat subcutaneous skin infections was evaluated by infecting C57BL/6 mice with a bioluminescent strain of S. aureus (Xen 36). Immunosuppressed mice were treated with either nisin F or sterile physiological saline 24 h and 48 h after infection with subcutaneously injected S. aureus Xen 36. Histology and bioluminescence flux measurements revealed that nisin F was ineffective in the treatment of deep dermal staphylococcal infections. Non-infected and infected mice treated with nisin F had an influx of polymorphonuclear cells in the deep stroma of the skin tissue. This suggested that nisin F, when injected subcutaneously, may have modulated the immune system. Nisin F proved an effective antimicrobial agent against S. aureus-related infections in the respiratory tract, but not against subcutaneous infections. The outcome of nisin F treatment thus depends on the route of administration and site of infection.
      13. URL :
        http://scholar.sun.ac.za/handle/10019.1/1285
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9042
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Journal of orthopaedic research: official publication of the Orthopaedic Research Society
      6. Products :
      7. Volume :
        27
      8. Issue :
        8
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Acinetobacter baumannii; Acinetobacter Infections; Animals; Anti-Bacterial Agents; Bioware; Colistin; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Female; Fractures, Bone; Mice; Mice, Inbred C57BL; Osteomyelitis; Xen29
      12. Abstract :
        Osteomyelitis (OM) from multidrug-resistant (MDR) Acinetobacter has emerged in >30% of combat-related injuries in Iraq and Afghanistan. While most of these strains are sensitive to colistin, the drug is not available in bone void fillers for local high-dose delivery. To address this, we developed a mouse model with MDR strains isolated from wounded military personnel. In contrast to S. aureus OM, which is osteolytic and characterized by biofilm in necrotic bone, A. baumannii OM results in blastic lesions that do not contain apparent biofilm. We also found that mice mount a specific IgG response against three proteins (40, 47, and 56 kDa) regardless of the strain used, suggesting that these may be immuno-dominant antigens. PCR for the A. baumannii-specific parC gene confirmed a 100% infection rate with 75% of the MDR strains, and in vitro testing confirmed that all strains were sensitive to colistin. We also developed a real-time quantitative PCR (RTQ-PCR) assay that could detect as few as 10 copies of parC in a sample. To demonstrate the efficacy of colistin prophylaxis in this model, mice were treated with either parenteral colistin (0.2 mg colistinmethate i.m. for 7 days), local colistin (PMMA bead impregnated with 1.0 mg colistin sulfate), or an unloaded PMMA bead control. While the parenteral colistin failed to demonstrate any significant effects versus the placebo, the colistin PMMA bead significantly reduced the infection rate such that only 29.2% of the mice had detectable levels of parC at 19 days (p < 0.05 vs. i.m. colistin and placebo).
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19173261
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9043
      1. Author :
        Ghali, Shadi; Bhatt, Kirit A; Dempsey, Marlese P; Jones, Deidre M; Singh, Sunil; Aarabi, Shahram; Arabi, Shahram; Butler, Peter E; Gallo, Robert L; Gurtner, Geoffrey C
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Plastic and reconstructive surgery
      6. Products :
      7. Volume :
        123
      8. Issue :
        4
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Bioware; Cathelicidins; Chronic Disease; Drug Carriers; Genetic Engineering; Male; Rats; Rats, Inbred F344; Surgical Flaps; Wound Infection; Xen29
      12. Abstract :
        BACKGROUND The success of antimicrobial therapy has been impaired by the emergence of resistant bacterial strains. Antimicrobial peptides are ubiquitous proteins that are part of the innate immune system and are successful against such antibiotic-resistant microorganisms. The authors have previously demonstrated the feasibility of protein delivery via microvascular free flap gene therapy and here they examine this approach for recalcitrant infections. METHODS The authors investigated the production of the human cathelicidin antimicrobial peptide-LL37, delivered by ex vivo transduction of the rodent superficial inferior epigastric free flap with Ad/CMV-LL37. The vascular permeabilizing agent vascular endothelial growth factor (VEGF) was co-administered during ex vivo transduction with adenoviral vectors in an attempt to augment transduction efficiency. A rodent model of chronic wound/foreign body infection seeded with bioluminescent Staphylococcus aureus was used to assess the biological efficacy of delivering therapeutic antimicrobial genes using this technology. RESULTS The authors were successful in demonstrating significant LL37 expression, which persisted for 14 days after ex vivo transduction with Ad/CMV-LL37. Transduction efficiency was significantly improved with the co-administration of 5 micrograms of VEGF during transduction without significantly increasing systemic dissemination of adenovirus or systemic toxicity. They were able to demonstrate in the rodent model of chronic wound/foreign body infections a significant reduction in bacterial loads from infected catheters following transduction with Ad/CMV-LL37 and increased bacterial clearance. CONCLUSION This study demonstrates for the first time that microbicidal gene therapy via microvascular free flaps is able to clear chronic infections such as occurs with osteomyelitis resulting from trauma or an infected foreign body [corrected]
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19337084
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9040
      1. Author :
        N/A
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Infection and immunity
      6. Products :
      7. Volume :
        77
      8. Issue :
        7
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Animal Structures; Animals; Antibodies, Bacterial; Antigens, Bacterial; Bacterial Proteins; Bioware; Cell Wall; Colony Count, Microbial; Female; Humans; Mice; Mice, Inbred BALB C; Neutrophils; Opsonin Proteins; Proteome; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Staphylococcal Infections; Staphylococcal Vaccines; Staphylococcus aureus; Vaccines, Subunit; Vaccines, Synthetic; Whole Body Imaging; Xen29
      12. Abstract :
        Staphylococcus aureus is an important human pathogen with increasing clinical impact due to the extensive spread of antibiotic-resistant strains. Therefore, development of a protective polyvalent vaccine is of great clinical interest. We employed an intravenous immunoglobulin (IVIG) preparation as a source of antibodies directed against anchorless S. aureus surface proteins for identification of novel vaccine candidates. In order to identify such proteins, subtractive proteome analysis (SUPRA) of S. aureus anchorless cell wall proteins was performed. Proteins reacting with IVIG but not with IVIG depleted of S. aureus-specific opsonizing antibodies were considered vaccine candidates. Nearly 40 proteins were identified by this preselection method using matrix-assisted laser desorption ionization--time of flight analysis. Three of these candidate proteins, enolase (Eno), oxoacyl reductase (Oxo), and hypothetical protein hp2160, were expressed as glutathione S-transferase fusion proteins, purified, and used for enrichment of corresponding immunoglobulin Gs from IVIG by affinity chromatography. Use of affinity-purified anti-Eno, anti-Oxo, and anti-hp2160 antibodies resulted in opsonization, phagocytosis, and killing of S. aureus by human neutrophils. High specific antibody titers were detected in mice immunized with recombinant antigens. In mice challenged with bioluminescent S. aureus, reduced staphylococcal spread was measured by in vivo imaging. The recovery of S. aureus CFU from organs of immunized mice was diminished 10- to 100-fold. Finally, mice immunized with hp2160 displayed statistically significant higher survival rates after lethal challenge with clinically relevant S. aureus strains. Taken together, our data suggest that anchorless cell wall proteins might be promising vaccine candidates and that SUPRA is a valuable tool for their identification.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19364833
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9039
      1. Author :
        Li, Min; Rigby, Kevin; Lai, Yuping; Nair, Vinod; Peschel, Andreas; Schittek, Birgit; Otto, Michael
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Antimicrobial agents and chemotherapy
      6. Products :
      7. Volume :
        53
      8. Issue :
        10
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Anti-Bacterial Agents; Bioware; Blotting, Southern; Chromatography, Thin Layer; Computational Biology; Cytochromes c; Genetic Complementation Test; Humans; Microscopy, Electron, Scanning; Microscopy, Immunoelectron; Mutagenesis; Peptides; Phospholipids; Polymerase Chain Reaction; Staphylococcus aureus; Xen36
      12. Abstract :
        Antimicrobial peptides (AMPs) form an important part of the innate host defense. In contrast to most AMPs, human dermcidin has an anionic net charge. To investigate whether bacteria have developed specific mechanisms of resistance to dermcidin, we screened for mutants of the leading human pathogen, Staphylococcus aureus, with altered resistance to dermcidin. To that end, we constructed a plasmid for use in mariner-based transposon mutagenesis and developed a high-throughput cell viability screening method based on luminescence. In a large screen, we did not find mutants with strongly increased susceptibility to dermcidin, indicating that S. aureus has no specific mechanism of resistance to this AMP. Furthermore, we detected a mutation in a gene of unknown function that resulted in significantly increased resistance to dermcidin. The mutant strain had an altered membrane phospholipid pattern and showed decreased binding of dermcidin to the bacterial surface, indicating that dermcidin interacts with membrane phospholipids. The mode of this interaction was direct, as shown by assays of dermcidin binding to phospholipid preparations, and specific, as the resistance to other AMPs was not affected. Our findings indicate that dermcidin has an exceptional value for the human innate host defense and lend support to the idea that it evolved to evade bacterial resistance mechanisms targeted at the cationic character of most AMPs. Moreover, they suggest that the antimicrobial activity of dermcidin is dependent on the interaction with the bacterial membrane and might thus assist with the determination of the yet unknown mode of action of this important human AMP.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19596877
      14. Call Number :
        PKI @ catherine.lautenschlager @
      15. Serial :
        9983
      1. Author :
        Pozo, J. L. del; Rouse, M. S.; Mandrekar, J. N.; Sampedro, M. F.; Steckelberg, J. M.; Patel, R.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Antimicrobial Agents and Chemotherapy
      6. Products :
      7. Volume :
        53
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        IVIS, Xenogen, Xen30, Xen5, Xen41
      12. Abstract :
        Bacterial biofilms are resistant to conventional antimicrobial agents. Prior in vitro studies have shown that electrical current (EC) enhances the activities of aminoglycosides, quinolones, and oxytetracycline against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus epidermidis, Escherichia coli, and Streptococcus gordonii. This phenomenon, known as the bioelectric effect, has been only partially defined. The purpose of this work was to study the in vitro bioelectric effect on the activities of 11 antimicrobial agents representing a variety of different classes against P. aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and S. epidermidis. An eight-channel current generator/controller and eight chambers delivering a continuous flow of fresh medium with or without antimicrobial agents and/or EC to biofilm-coated coupons were used. No significant decreases in the numbers of log10 CFU/cm2 were seen after exposure to antimicrobial agents alone, with the exception of a 4.57-log-unit reduction for S. epidermidis and trimethoprim-sulfamethoxazole. We detected a statistically significant bioelectric effect when vancomycin plus 2,000 microamperes EC were used against MRSA biofilms (P = 0.04) and when daptomycin and erythromycin were used in combination with 200 or 2,000 microamperes EC against S. epidermidis biofilms (P = 0.02 and 0.0004, respectively). The results of these experiments indicate that the enhancement of the activity of antimicrobial agents against biofilm organisms by EC is not a generalizable phenomenon across microorganisms and antimicrobial agents.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/18725436
      14. Call Number :
        137347
      15. Serial :
        5991
      1. Author :
        Pozo, J. L. del; Rouse, M. S.; Mandrekar, J. N.; Steckelberg, J. M.; Patel, R.
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Antimicrob Agents Chemother
      6. Products :
      7. Volume :
        53
      8. Issue :
        N/A
      9. Page Numbers :
        N/A
      10. Research Area :
        N/A
      11. Keywords :
        Aza Compounds/pharmacology, Biofilms/drug effects/*growth & development, Electricity/*adverse effects, Pseudomonas/drug effects/*growth & development, Quinolines/pharmacology, Staphylococcus/drug effects/*growth & development, Tobramycin/pharmacology IVIS, Xenogen, Xen30
      12. Abstract :
        The activity of electrical current against planktonic bacteria has previously been demonstrated. The short-term exposure of the bacteria in biofilms to electrical current in the absence of antimicrobials has been shown to have no substantial effect; however, longer-term exposure has not been studied. A previously described in vitro model was used to determine the effect of prolonged exposure (i.e., up to 7 days) to low-intensity (i.e., 20-, 200-, and 2,000-microampere) electrical direct currents on Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis biofilms. Dose- and time-dependent killing was observed. A maximum of a 6-log(10)-CFU/cm(2) reduction was observed when S. epidermidis biofilms were exposed to 2,000 microamperes for at least 2 days. A 4- to 5-log(10)-CFU/cm(2) reduction was observed when S. aureus biofilms were exposed to 2,000 microamperes for at least 2 days. Finally, a 3.5- to 5-log(10)-CFU/cm(2) reduction was observed when P. aeruginosa biofilms were exposed to electrical current for 7 days. A higher electrical current intensity correlated with greater decreases in viable bacteria at all time points studied. In conclusion, low-intensity electrical current substantially reduced the numbers of viable bacteria in staphylococcal or Pseudomonas biofilms, a phenomenon we have labeled the “electricidal effect.”
      13. URL :
        http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18955534
      14. Call Number :
        137350
      15. Serial :
        7845
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