Total knee arthroplasty (TKA) is the largest major surgical procedure by volume for Medicare, and infection is the largest reason for TKA revision. Irrigation and debridement (I&D) with long-term antibiotics is the preferred method to manage periprosthetic joint infection (PJI; infected TKA). I&D fails in approximately 60% of cases. The high failure rate of I&D is a result of the high tolerance of biofilm to antibiotics. There is a large gap in knowledge in how biofilm develops antibiotic tolerance, how it is regulated, and there are no strategies to disrupt this tolerance in PJI. The hypothesis of this proposal is that bacterial persisters, a subpopulation of bacteria phenotypically resistant to antibiotics, are a major factor responsible for this tolerance and the high failure rate of I&D. In other diseases of chronic infection (ie tuberculosis and cystic fibrosis), bacterial persisters have been well-recognized to increase biofilm tolerance to antibiotics and prevent eradication of the infection. Demonstrating bacterial persisters are present in PJI biofilm is the first step in developing treatment strategies.
The aims i nclude establishing the presence of bacterial persisters in biofilm of PJI and identify potential therapeutic strategies to decrease biofilm antibiotic tolerance for later clinical trials. Preliminary results in this proposal demonstrate bacterial persisters provide a major contribution to biofilm antibiotic tolerance, and that this tolerance is associated with increased toxin-antitoxin expression in vitro.
In Aim 1, a clinical study will be completed to determine whether these same results are observed on clinical samples.
In Aim 2, we will determine the role of toxin-antitoxin systems in PJI biofilm antibiotic tolerance in the animal model we have developed.
In Aim 3, the efficacy of a new class of antibiotics, ADEP4, that is not dependent on active metabolism or a positive energy state to eradicate bacteria will be quantified. This will add further evidence to the role of bacterial persisters in PJI and offer an additional new therapeutic strategy for later clinical trials. The research plan is tightly integrated with a five-year career development plan where Dr. Urish will be mentored by a multidisciplinary team of research and clinical investigators in orthopaedic surgery, microbiology, and biostatistics. Mentors were selected based on already existing relationships, methodological expertise, and success in mentoring previous junior investigators. The mentoring team is a tremendous strength in this proposal as they compromise a diverse and complimentary skill set. To achieve his training objectives, a combination of classes, workshops, and conferences scheduled throughout the proposal will provide the foundation to acquire new skills in advanced bacterial genetic techniques, analysis, and their application into translational clinical studies. Together, the generated preliminary data and mentoring will create a foundation for Dr. Urish?s transition to independence with R01 funded research.

Public Health Relevance

The most severe complication in total knee arthroplasty is periprosthetic joint infection, and the preferred treatment option, debridement with component retention, has a high failure rate at 60%. In part, this high failure rate is secondary to the high antibiotic tolerance of the biofilm established on the implant. Understanding biofilm antibiotic tolerance in periprosthetic joint infection will contribute to novel therapies that can improve treatment and outcomes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Clinical Investigator Award (CIA) (K08)
Project #
1K08AR071494-01
Application #
9293639
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Program Officer
Washabaugh, Charles H
Project Start
2017-06-01
Project End
2022-04-30
Budget Start
2017-06-01
Budget End
2018-04-30
Support Year
1
Fiscal Year
2017
Total Cost
$166,016
Indirect Cost
$12,216
Name
University of Pittsburgh
Department
Orthopedics
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Khare, Rahul; Jaramaz, Branislav; Hamlin, Brian et al. (2018) Implant orientation accuracy of a hand-held robotic partial knee replacement system over conventional technique in a cadaveric test. Comput Assist Surg (Abingdon) 23:8-13
Casper, Michael; Mitra, Riddhit; Khare, Rahul et al. (2018) Accuracy assessment of a novel image-free handheld robot for Total Knee Arthroplasty in a cadaveric study. Comput Assist Surg (Abingdon) 23:14-20
Urish, Kenneth L; Qin, Yongmei; Li, Benjamin Y et al. (2018) Predictors and Cost of Readmission in Total Knee Arthroplasty. J Arthroplasty 33:2759-2763
Urish, Kenneth L; Bullock, Andrew G; Kreger, Alexander M et al. (2018) A Multicenter Study of Irrigation and Debridement in Total Knee Arthroplasty Periprosthetic Joint Infection: Treatment Failure Is High. J Arthroplasty 33:1154-1159
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