SAT0696-HPR THE PREVALENCE OF SEPTIC ARTHRITIS AT A LARGE UNIVERSITY TEACHING HOSPITAL
Authors: Caroline Atherton, Kathryn Mccall, Neal L. Millar, Yianni Joannidis, Tom Evans, Iain Mcinnes
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Septic arthritis (SA) is a rheumatological emergency requiring early treatment to prevent lasting joint damage. Treatment outcomes depend on prompt diagnosis, which currently rests on clinical suspicison, riased non-specifc inflammaotry markers and identification of a pathogen from synovial fluid. <h3>Objectives:</h3> To establish the prevalence of SA in a large University teaching hospital. To review the microbiology results and identified pathogens in each positive case along with subsequent treatment regimes utilising outpatinet parenteral antimicrobial therapy (OPAT) with adherence to local guidelines. <h3>Methods:</h3> Retrospective data collection of all samples identified as synovial fluid or joint aspiration sent to microbiology lab between 1<sup>st</sup>January 2016 and 31<sup>st</sup> December 2016. Electronic review of microbiology results to identify the causal pathogen and case notes to review treatment and outcomes. <h3>Results:</h3> There were 364 samples identified as joint aspirate or synovial fluid, 54 of these grew a pathogen. Positive aspirates from native joints totaled 35 in 31 patients. Twenty-three of these patients accounting for 25 of the positive samples were treated clinically as SA. Sub analysis of this group revealed <i>Staph.aureus</i> was the most commonly identified pathogen in 14 cases (56%). There were however 8 other pathogens identified in the 25 positive samples. Fifteen patients (65%) underwent a joint washout in theatre, 7 of these patients had multiple washouts. Duration of antibiotic therapy was 5 weeks in 8 cases; 13 cases had therapy for &gt;5 weeks and 2 cases with SA in the upper limb had treatment for &lt; 5 weeks. There were 10 positive samples taken from 8 native joints that grew a pathogen and were not treated as SA. These were identified on enrichment culture only n=3 or an alternative clinical diagnosis was clearly documented n=4. One case was incorrectly labeled as a joint aspirate. The remaining positive samples, 17 in 12 patients, came from prosthetic joint aspirates. <h3>Conclusion:</h3> In line with known literature, <i>staph.aureus</i> was the most common pathogen<sup>1</sup>, however there were a number of other bacteria identified which needs to be taken into account when formulating local antimicrobial guidelines. Current literature reports surgical treatment as not superior to medical<sup>2</sup>, yet 65% of cases here under went joint lavage in theatre. This information will be used to inform local clinical practice, and, guide recruitment targets for a large multi-centre study collecting data and samples from patients presenting with a hot swollen joint, with the aim of identifying a specific biomarker for SA. <h3>References</h3> [1] Rutherford A I, Kleymann A, Ibrahim F, Galloway J. The increasing incidence of septic arthritis in England between 1998 and 2013. Rheumatology April 2016 55(1):i51-i52 [2] Ravindran V, Logan I, Bourke B E. Medical vs Surgical treatment for the native joint in septic arthritis: A 6 year, single UK academic centre experience. RheumatologyOct200948(10):1320-1322 <h3>Disclosure of Interests:</h3> Caroline Atherton: None declared, Kathryn McCall: None declared, Neal L Millar: None declared, Yianni Joannidis: None declared, Tom Evans: None declared, Iain McInnes Grant/research support from: AstraZeneca, Celgene, Compugen, Novartis, Roche, UCB Pharma, Consultant for: AbbVie, Celgene, Galvani, Lilly, Novartis, Pfizer, UCB Pharma