Purpose: This study aims to use proteomic profiling of sonicate fluid samples to compare host response during Staphylococcus aureus-associated periprosthetic joint infection (PJI) and non-infected arthroplasty failure (NIAF) and investigate novel biomarkers to increase diagnostic accuracy. Experimental Design: In this pilot study, eight sonicate fluid samples (four from NIAF and four from Staphylococcus aureus PJI) were studied. Samples were reduced, alkylated and trypsinized overnight, followed by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) on a high-resolution Orbitrap Eclipse mass spectrometer. MaxQuant software suite was used for protein identification, filtering, and label-free quantitation. Results: Principal component analysis of the identified proteins clearly separated S. aureus PJI and NIAF samples. Overall, 810 proteins were quantified in any three samples from each group and 35 statistically significant differentially abundant proteins (DAPs) were found (2-sample t-test p-values ≤0.05 and log2fold-change values ≥2 or ≤-2). Gene ontology pathway analysis found that microbial defense responses, specifically those related to neutrophil activation, were increased in S. aureus PJI compared to NIAF samples. Conclusion and Clinical Relevance: Proteomic profiling of sonicate fluid using LC-MS/MS, alone or in combination with complementary protein analyses, differentiated S. aureus PJI and NIAF in this pilot study.

RP reports grants from ContraFect, TenNor Therapeutics Limited, and BioFire. RP is a consultant to PhAST, Torus Biosystems, Day Zero Diagnostics, Mammoth Biosciences, and HealthTrackRx; monies are paid to Mayo Clinic. Mayo Clinic and RP have a relationship with Pathogenomix. RP has research supported by Adaptive Phage Therapeutics. Mayo Clinic has a royalty-bearing know-how agreement and equity in Adaptive Phage Therapeutics. RP is also a consultant to Netflix, Abbott Laboratories, and CARB-X. In addition, RP has a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued. RP receives honoraria from the NBME, Up-to-Date and the Infectious Diseases Board Review Course. MPA receives royalties from Stryker on certain hip and knee products and serve on the AAOS Board of Directors. All other authors report no conflicts of interest.

This research was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number NIH R01 AR056647. CF was supported by the Mayo Clinic Graduate School of Biomedical Sciences and the Ph.D. Training Grant in Basic Immunology (NIAID T32 AI07425-25). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

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The Institutional Review Board of Mayo Clinic gave ethical approval of this work (#09-000808).

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The mass spectrometry proteomics data have been deposited to the Proteome Xchange Consortium via the PRIDE partner repository with the dataset identifier PXD038928.