2285. Emergence of perioperative antibiotic non-susceptible pathogens causing prosthetic joint infections in monomicrobial Gram-negative and polymicrobial infections.

Background Current recommendations by Infectious diseases society of America (IDSA) endorse cefazolin for perioperative use. What is less known currently is the emergence of resistance in Gram-positive (GP) and Gram-negative (GN) prosthetic joint infections (PJIs) in the setting of perioperative use of antibiotics. Methods A retrospective multi-centric cohort was studied at three hospitals from January 2012 to December 2018. Patients with PJIs were identified using ICD codes. We reviewed electronic medical records and identified PJIs which followed primary arthroplasties. We included cases where perioperative antibiotics records were available. Results 66 infected PJIs with available preoperative records were included. 40 (61%) patients were females, and 42 (64%) were caucasians. Indications for undergoing arthroplasty were degenerative joint disease (DJD) in 52 (78%), trauma in 13 (20%) and avascular necrosis in 1 (1.5%). Sites for arthroplasty were knee in 33 (50%), hip 28 (42.5%), shoulder 4 (6%), and ankle in 1(1.5%). 43 (65%) had GP monomicrobial, 6 (9%) had GN monomicrobial and 17 (26%) had polymicrobial infections. 40 (60.5%) patients received cefazolin, 25 (38%) received vancomycin and 1 (1.5%) received ceftriaxone as perioperative prophylaxis. 7 (11%) PJIs among monomicrobial infections and 6 (35%) among polymicrobial infections had non-susceptible (NS) organisms (Figure 1 and 2). 8 (47%) polymicrobial PJIs had a mixed susceptibility profile with drug susceptible and resistant organisms. Conclusion In general, when monomicrobial GP pathogens are causative for PJI, current use of cefazolin as perioperative drug of choice is sound and we agree with the current perioperative recommendations. It should be recognized that in situations where the PJI is due to GN or is polymicrobial, resistance to perioperative antibiotics may be present at a greater rate. From this study we conclude that in cases where the pathogen is known to be GN or polymicrobial from a diagnostic aspiration, then a broader antibiotic selection may be of benefit perioperatively. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]