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You searched for subject:(implant associated infection). Showing records 1 – 3 of 3 total matches.

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1. Johnson, Christopher T. Lysostaphin-delivering hydrogels to treat orthopaedic device infections.

Degree: PhD, Biomedical Engineering (Joint GT/Emory Department), 2018, Georgia Tech

Orthopaedic hardware infections are a significant clinical problem with current therapies limited to surgical debridement and systemic antibiotic regimens. Lysostaphin is a bacteriolytic enzyme with high anti-staphylococcal activity. We engineered a lysostaphin-delivering injectable poly(ethylene glycol) (PEG) hydrogel to treat Staphylococcus aureus infections in bone fractures and segmental defections. The injectable hydrogel formulation conforms and adheres to the injury and surrounding tissue, ensuring efficient, local delivery of lysostaphin. The objective of this work is to engineer novel lysostaphin-delivering hydrogels to reduce infection and enhance bone repair in murine models of implant-associated orthopaedic infection. The central hypothesis is that controlled delivery of lysostaphin from our osseo-repartive hydrogels will reduce infection and allowing for bone repair to occur. We engineered PEG hydrogels that release active lysostaphin in response to local environmental cues. The hydrogel delivery vehicle enhances lysostaphin stability thereby preserving antimicrobial activity. Lysostaphin-delivering hydrogels eradicate S. aureus infection and support fracture healing of a pin-stabilized fracture infection model. Co-delivery of lysostaphin and BMP-2 to a model of segmental bone defect infection results in the simultaneous elimination of bacteria and bone regeneration. BMP-2 loaded lysostaphin-delivering hydrogels regenerated bone with mechanical integrity. Importantly, these hydrogels restore the local inflammatory environment, as assessed by cytokine and inflammatory cell profiling, to that of a sterile wound by one week. Administration of lysostaphin-delivering hydrogel therapy to established S. aureus infections results in an infection reduction that is potentiated with the addition of systemic antibiotic therapy. These findings support the further development of lysostaphin delivering hydrogels to treat device associated infections. This work is innovative and significant because it establishes a local strategy to effectively reduce bacterial infections while simultaneously supporting bone healing. Advisors/Committee Members: García, Andrés J. (advisor), Donlan, Rodney M. (committee member), Guldberg, Robert E. (committee member), Westblade, Lars F. (committee member), Botchwey, Edward A. (committee member).

Subjects/Keywords: Orthopaedic implant infection; Biomaterials associated infection; Lysostaphin; Hydrogel; Bone repair; Drug delivery

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Johnson, C. T. (2018). Lysostaphin-delivering hydrogels to treat orthopaedic device infections. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61143

Chicago Manual of Style (16th Edition):

Johnson, Christopher T. “Lysostaphin-delivering hydrogels to treat orthopaedic device infections.” 2018. Doctoral Dissertation, Georgia Tech. Accessed December 04, 2020. http://hdl.handle.net/1853/61143.

MLA Handbook (7th Edition):

Johnson, Christopher T. “Lysostaphin-delivering hydrogels to treat orthopaedic device infections.” 2018. Web. 04 Dec 2020.

Vancouver:

Johnson CT. Lysostaphin-delivering hydrogels to treat orthopaedic device infections. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2020 Dec 04]. Available from: http://hdl.handle.net/1853/61143.

Council of Science Editors:

Johnson CT. Lysostaphin-delivering hydrogels to treat orthopaedic device infections. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/61143


Clemson University

2. Uzair, Unaiza. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.

Degree: PhD, Chemistry, 2020, Clemson University

Implant-associated infection is a leading cause of fixation failures and these infections are resistant to antibiotics especially after mature biofilms have been established on the implant surface. These infections can also be challenging to detect, especially at early stages or during antibiotic treatment, due to lack of symptoms and specific tests to detect localized infection. Low pH is believed to be associated with infection as bacteria and inflammatory responses can cause a pH drop in the affected area. Detecting changes in pH on the implant surface can provide a better understanding and help to detect, treat and monitor such infections more effectively thereby reducing the need for revision surgeries. We developed a novel X-ray Excited Luminescence Chemical Imaging (XELCI) technique to measure surface specific chemical concentrations with sub-millimeter spatial resolution. A focused X-ray beam (~0.3 mm) passes through tissue and irradiates scintillators coated on an orthopedic implant; these scintillators generate visible and near infrared light which is partially absorbed by a pH indicator film (e.g., bromocresol green or bromothymol blue pH dye encapsulated in a PEG hydrogel) altering the luminescence spectrum in a pH-dependent manner. Images are acquired by scanning the beam point-by-point and measuring the spectrum at each point. We developed, synthesized and tested pH indicator films and measured the signal intensity, noise level, and knife-edge spatial resolution through varying thicknesses of chicken breast tissue and through 11 mm of human cadaveric tissue in a tibial fixation specimen. For example, we observed a knife-edge (80/20) spatial resolution of ~0.5 mm through up to 1 cm of tissue and an average pH noise level of 0.25 ±0.05 pH units. We also implanted the pH sensor in rabbits to image pH during infection. The in vivo studies found that the sensors continued to function well for the 11-day experiments. During infection, the pH did not significantly drop compared to uninfected implants on opposite legs (<0.5 pH unit change). For sensors that were initially acidic and infected, the pH neutralized in time, and this neutralization could be delayed by enclosing the implant in cavity with a 1 mm aperture to slow perfusion and diffusion. These studies show applicability provide useful insight into the pH changes that occur on implant surface during infection and can have important implications for antibiotic treatments. Future directions include improving the collection efficiency, adding an X-ray chopper to measure background signal and luminescence lifetime, scanning scintillator nanoparticles in three dimensions for tomography, detecting additional analytes, and studying pH changes on the device surface during infection followed by antibiotic treatment in animal models and to develop a model for pH changes during osteomyelitis. Advisors/Committee Members: Jeffrey N Anker, Tzuen-Rong Tzeng, Stephen Creager, Carlos D Garcia, Jason D McNeil.

Subjects/Keywords: bioimaging; implant associated infection; in vivo pH mapping; pH sensing; X-ray scintillation; XELCI

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Uzair, U. (2020). A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2655

Chicago Manual of Style (16th Edition):

Uzair, Unaiza. “A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.” 2020. Doctoral Dissertation, Clemson University. Accessed December 04, 2020. https://tigerprints.clemson.edu/all_dissertations/2655.

MLA Handbook (7th Edition):

Uzair, Unaiza. “A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.” 2020. Web. 04 Dec 2020.

Vancouver:

Uzair U. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Dec 04]. Available from: https://tigerprints.clemson.edu/all_dissertations/2655.

Council of Science Editors:

Uzair U. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2655


University of Gothenburg / Göteborgs Universitet

3. Zaborowska, Magdalena N. On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants.

Degree: 2018, University of Gothenburg / Göteborgs Universitet

Orthopaedic implants enable the restitution of locomotor function and improve the quality of life of many people. However, biomaterial-associated infection may occur due to the propensity of microorganisms to adhere and colonize implant surfaces. The objective was to gain knowledge on the pathogenesis of infections associated with percutaneous osseointegrated implants for lower limb amputation prostheses. The aims were to design in vitro methods for the evaluation of antimicrobial surface properties, evaluate a novel method for biofilm-susceptibility testing and characterising virulence factors in bacterial isolates from patients with implant-associated osteomyelitis, and to investigate extracellular vesicle (EV)-host cell and EV-bacterial cell interactions. Results demonstrated that several methods, tailored to the specific surface modification and antimicrobial mode of action, should be applied to provide complementary information when evaluating the prophylactic and treatment effects of antimicrobial surfaces on planktonic and biofilm bacteria. The majority of clinical isolates of Staphylococcus spp. and Enterococcus spp. causing osteomyelitis were biofilm producers that required higher antimicrobial concentrations compared with non-producers. The biofilm susceptibility testing method may be useful to guide antimicrobial treatment decisions in orthopaedic implant-associated infection. All staphylococcal strains were able to produce EVs in vitro. A significantly higher level of cytotoxicity was induced in THP-1 monocytes by EVs compared with unstimulated controls. THP-1 cells internalised EVs and secreted proinflammatory cytokines to a greater degree than controls. Sub-inhibitory concentrations of gentamycin increased secretion of EVs and their protein content in S. epidermidis. EVs may play a role as survival factors by modulating cell growth and adherence to surfaces. In conclusion, isolates from implant-associated infection reveal multiple virulence traits relevant for understanding and treating these infections. This thesis proposes EVs as a novel pathogenic mechanism of biomaterial-associated infection, requiring further research focus.

Subjects/Keywords: osseointegration; amputation prosthesis; implant-associated infection; biofilm; staphylococci; extracellular vesicles; host defence; cytokines; cell death

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zaborowska, M. N. (2018). On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants. (Thesis). University of Gothenburg / Göteborgs Universitet. Retrieved from http://hdl.handle.net/2077/56926

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Zaborowska, Magdalena N. “On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants.” 2018. Thesis, University of Gothenburg / Göteborgs Universitet. Accessed December 04, 2020. http://hdl.handle.net/2077/56926.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Zaborowska, Magdalena N. “On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants.” 2018. Web. 04 Dec 2020.

Vancouver:

Zaborowska MN. On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants. [Internet] [Thesis]. University of Gothenburg / Göteborgs Universitet; 2018. [cited 2020 Dec 04]. Available from: http://hdl.handle.net/2077/56926.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zaborowska MN. On the pathogenesis of infections associated with percutaneous osseointegrated orthopaedic implants. [Thesis]. University of Gothenburg / Göteborgs Universitet; 2018. Available from: http://hdl.handle.net/2077/56926

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.