252. Joint Decisions: Optimal Duration of Chronic Suppressive Antibiotics in Adults with Prosthetic Joint Infections Who Underwent Debridement, Antibiotics, Irrigation, and Retention of Prostheses

Background

Hip and knee arthroplasties are associated with complications including prosthetic joint infections (PJI). Management ranges from explantation to debridement, antibiotics, irrigation, and retention of prostheses (DAIR). In DAIR, patients receive intravenous antibiotics followed by chronic suppressive antibiotics. Current guidelines on suppressive antibiotic use after DAIR are unclear and based on expert consensus. This study seeks to elucidate the optimal duration of chronic suppressive antibiotics after DAIR.

Methods

This is a retrospective cohort study of adults in the Southern California Kaiser Permanente System with hip and knee prosthetic joint infections who underwent DAIR from 2007-2017. Culture data and durations of suppressive antibiotics were collected and patients were followed for 1 year after completion. Treatment failure was determined by mortality, re-infection, or prosthesis removal. Patients who received no antibiotics vs. less than 3 months vs 3 to 6 months vs greater than 1 year were compared.

Results

350 charts were reviewed and 145 patients were included. There were 87 knee and 58 hip PJIs with 32 patients (22%) who failed treatment. There were more cases of failure when patients didn’t receive suppressive antibiotics (27%) vs those who received any (19%), however the results were not significant. There were no significant differences in failure rates between short vs longer suppressive antibiotic courses regardless of the duration (Staph vs non-Staph, hip vs knee). Patients with Staphyloccocal infections and knee infections were significantly more likely to fail treatment (p=0.0196 & 0.0150, logistic regression).

Conclusion

This study shows the importance of suppression with oral antibiotics after PJIs are treated with DAIR. The lack of difference in treatment failure between the durations of suppressive antibiotics makes it prudent to consider shorter courses of antibiotics, while placing attention on patients with knee and Staphylococcal infections as they are more likely to fail treatment. Limitations include sample size, difficulty in quantifying extent of initial infection and debridement, and provider dependent prolonging of antibiotic duration.

Disclosures

All Authors: No reported disclosures

Mycobacterium scrofulaceum disease: experience from a tertiary medical centre and review of the literature

Introduction: Mycobacterium scrofulaceum infection has been identified in cases of paediatric cervical lymphadenitis but is less well defined in adults. To further characterize manifestations of M. scrofulaceum disease and treatment approaches, we reviewed our medical centre's experience and other published reports. Methods: We performed a retrospective chart review of patients at our medical centre with a positive M. scrofulaceum culture over a 15-year period. We compare our findings with those published in the literature to identify commonalities in disease presentations and treatment outcomes. Results: We identified 17 patients in our centre with positive M. scrofulaceum cultures, 10 of whom were diagnosed with clinical infection. The types of disease encountered included pulmonary and pleural infection (4), bone and joint infections with a foreign body (2), skin and soft tissue infection (2), brain abscess (1) and paediatric cervical adenitis (1). Structural lung disease was a common finding in cases of pulmonary infection. All adult patients except those with bone and joint infections had some type of immunomodulatory condition and/or structural lung disease. In seven patients, M. scrofulaceum was isolated in urinary or respiratory cultures without signs of clinical disease. Conclusion: M. scrofulaceum is a rare cause of non-tuberculosis mycobacterial infection in humans but can infect any tissue. Adults with pulmonary disease often have underlying structural lung disease, and those with extrapulmonary disease commonly have immunosuppressive conditions or foreign body-associated infections. Treatment outcomes are generally favourable; however, in patients with pulmonary M. scrofulaceum disease prognosis is more guarded.