322. Evaluation of the BioFire® Bone and Joint Infection (BJI) Panel for the Detection of Microorganisms and Antimicrobial Resistance Genes in Synovial Fluid Specimens

Abstract

Conclusion: MSKI in PWID continue to be found in younger persons with relatively few comorbidities. The infections predominantly involve the axial skeleton and are caused most often by Staphylococcus aureus. Gram-negative infections also occur and are due to environmental bacteria. Spinal infections were managed medically whereas infections of peripheral joints were also managed with surgery. An unfortunate number had relapse of infection, died or were lost to follow-up at 1 year, demonstrating the challenges of managing MSKI in this unique population Disclosures: All Authors: No reported disclosures 322 Session: P-10. Bone and Joint Background: Bone and Joint Infections (BJIs) present with non-specific symptoms that may include pain, swelling, and fever and are associated with high morbidity and significant risk of mortality. BJIs can be caused by a variety of bacteria and fungi, including anaerobes and microorganisms that can be challenging to culture or identify by traditional microbiological methods. Clinicians primarily rely on culture to identify the pathogen(s) responsible for infection. The BioFire ® Bone and Joint Infection (BJI) Panel (BioFire Diagnostics, Salt Lake City, UT) is designed to detect 15 gram-positive bacteria (includ-ing seven anaerobes), 14 gram-negative bacteria (including one anaerobe), two yeast, and eight antimicrobial resistance (AMR) genes from synovial fluid specimens in about an hour. The objective of this study was to evaluate the performance of an Investigational Use Only (IUO) version of the BioFire BJI Panel compared to various reference methods. S234 • OFID 2020:7 (Suppl 1) • Poster Abstracts Methods: Remnant synovial fluid specimens, which were collected for routine clinical care at 13 study sites in the US and Europe, underwent testing using an IUO version of the BioFire BJI Panel. Performance of this test was determined by comparison to Standard of Care (SoC) consisting of bacterial culture performed at each study site according to their routine procedures. Results: A total of 1544 synovial fluid specimens were collected and tested with the BioFire BJI Panel. The majority of specimens were from knee joints (77.9%) and arthrocentesis (79.4%) was the most common collection method. Compared to SoC culture, overall sensitivity was 90.2% and specificity was 99.8%. The BioFire BJI Panel yielded a total of 268 Detected results, whereas SoC yielded a total of 215 positive results for on-panel analytes. Conclusion: The BioFire BJI Panel is a sensitive, specific, and robust test for rapid detection of a wide range of analytes in synovial fluid specimens. The number of microorganisms and resistance genes included in the BioFire BJI Panel, together with a reduced time-to-result and increased diagnostic yield compared to culture, is expected to aid in the timely diagnosis and appropriate management of BJIs. Session: P-10. Bone and Joint Background: Nocardia are Gram-positive filamentous bacteria that cause Nocardiosis, a rare opportunistic infection. The most common site of infection is the lungs, with metastatic spread usually to the central nervous system. Prosthetic joint infection due to Nocardia is very rare. Methods: We report the first case of prosthetic joint infection due to Nocardia veteran-elegans, and review the literature regarding Nocardia septic arthritis, with particular attention to prosthetic joint infection. Results: The patient was a 35 year old male with history of Hodgkin's Lymphoma for which he received chemotherapy previously, poorly controlled diabetes, motor vehicle accident in 2003 with right open tibial plateau fracture requiring hardware placement, who was admitted with a two week history of right knee pain and swelling. Knee aspiration revealed purulent fluid and synovial culture grew Nocardia species. He underwent right knee arthrotomy and debridement with removal of hardware. The Nocardia species was speciated as N. veterana-elegans, sensitive to trimethoprim/ sulfamethoxazole, linezolid, clarithromycin, imipenem and amikacin. He was placed on oral linezolid for four weeks, which was then switched to oral trimethoprim/sulfa-methoxazole, with a plan for a six month course of therapy. He has completed two months of therapy thus far and is doing well clinically. Nocardia is an uncommon cause of septic arthritis. We found only 37 cases reported in the English literature thus far. Amongst these, only six involved prosthetic joints, including our case, which is the first one to be caused by N. veterana-elegans.