Papers by Amanda H . Loftin
The Journal of bone and joint surgery. American volume, Jan 20, 2016
Postoperative infection is a devastating complication following arthroplasty. The goals of this s... more Postoperative infection is a devastating complication following arthroplasty. The goals of this study were to introduce a "smart" implant coating that combines passive elution of antibiotic with an active-release mechanism that "targets" bacteria, and to use an established in vivo mouse model of post-arthroplasty infection to longitudinally evaluate the efficacy of this polymer implant coating in decreasing bacterial burden. A novel, biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics both passively and actively. In vitro-release kinetics were studied using high-performance liquid chromatography (HPLC) quantification in conditions representing both the physiologic environment and the more oxidative, hyperinflammatory environment of periprosthetic infection. The in vivo efficacy of the PEG-PPS coating delivering vancomycin and tigecycline was tested using an established mouse mode...
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, Jan 26, 2016
Post-operative spine infections are a challenge, as hardware must often be retained to prevent de... more Post-operative spine infections are a challenge, as hardware must often be retained to prevent destabilization of the spine, and bacteria form biofilm on implants, rendering them inaccessible to antibiotic therapy and immune cells. A model of posterior-approach spinal surgery was created in which a stainless steel k-wire was transfixed into the L4 spinous process of 12-week-old C57BL/6 mice. Mice were then randomized to receive either one of three concentrations (1 × 10(2) , 1 × 10(3) , and 1 × 10(4) colony forming units (CFU)) of a bioluminescent strain of Staphylococcus aureus or normal saline at surgery. The mice were then longitudinally imaged for bacterial bioluminescence to quantify infection. The 1 × 10(2) CFU group had a decrease in signal down to control levels by POD 25, while the 1 × 10(3) and 1 × 10(4) CFU groups maintained a 10-fold higher signal through POD 35. Bacteria were then harvested from the pin and surrounding tissue for confirmatory CFU counts. All mice in the...
Metastatic Bone Disease, 2016
Journal of Investigative Medicine
Journal of Investigative Medicine
Journal of Investigative Medicine
Background: Vancomycin and Cefazolin are both widely used for intravenous prophylaxis against sur... more Background: Vancomycin and Cefazolin are both widely used for intravenous prophylaxis against surgical implant infections. The aim of this study was to compare the efficacy of low and high dose intravenous vancomycin or cefazolin alone and in combination with subcutaneous rifampin given as prophylactic therapy against a Staphylococcus epidermidis surgical implant infection model in mice. Methods: S. epidermidis was used to inoculate titaninum discs which were subsequently implanted subcutaneously. The efficacies of low versus high dose vancomycin (10 and 110mg/kg) and cefazolin (50 and 200mg/kg) intravenous prophylaxis plus/minus rifampin (25mg/kg) combination therapy were evaluated. Thesegroups were compared using in vivo bioluminescence imaging and ex vivo bacterial counts. Results: Low dose cefazolin resulted in decreased in vivo bioluminescent signals and lower CFUs harvested from both capsules and implants compared with sham treated mice (p<0.01). Low dose vancomycin had bio...
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2015
The purpose of this study was to determine what orthopaedic surgery department leadership charact... more The purpose of this study was to determine what orthopaedic surgery department leadership characteristics are most closely correlated with securing NIH funding and increasing scholarly productivity. Scopus database was used to identify number of publications/h-index for 4,328 faculty, department chairs (DC), and research directors (RD), listed on departmental websites from 138 academic orthopaedic departments in the United States. NIH funding data was obtained for the 2013 fiscal year. While all programs had a DC, only 46% had a RD. Of $54,925,833 in NIH funding allocated to orthopaedic surgery faculty in 2013, 3% of faculty and 31% of departments were funded. 16% of funded institutions had a funded DC whereas 65% had a funded RD. Department productivity and funding were highly correlated to leadership productivity and funding(p < 0.05). Mean funding was $1.70 million for departments with a NIH-funded RD, $104,000 for departments with an unfunded RD, and $72,000 for departments w...
The Scientific World Journal, 2013
Periprosthetic joint infections are devastating complications for patients and for our health sys... more Periprosthetic joint infections are devastating complications for patients and for our health system. With growing demand for arthroplasty, the incidence of these infections is projected to increase exponentially. This paper is a review of existing animal models to study periprosthetic infection aimed at providing scientists with a succinct presentation of strengths and weaknesses of available in vivo systems. These systems represent the tools available to investigate novel antimicrobial therapies and reduce the clinical and economic impact of implant infections.
Antimicrobial Agents and Chemotherapy, 2014
The incidence of infections related to cardiac devices (such as permanent pacemakers) has been in... more The incidence of infections related to cardiac devices (such as permanent pacemakers) has been increasing out of proportion to implantation rates. As management of device infections typically requires explantation of the device, optimal prophylactic strategies are needed. Cefazolin and vancomycin are widely used as single agents for surgical prophylaxis against cardiac device-related infections. However, combination antibiotic prophylaxis may further reduce infectious complications. To model a localized subcutaneous implant-related infection, a bioluminescent strain of Staphylococcus epidermidis was inoculated onto a medical-procedure-grade titanium disc, which was placed into a subcutaneous pocket in the backs of mice.
Journal of Nature and Science, Apr 1, 2015
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Papers by Amanda H . Loftin