424. Risk Factors for Infection or Colonization with Piperacillin-tazobactam (TZP) Resistant <i>P. aeruginosa</i> (PSA) with Increasing Degrees of β-lactam Resistance

Abstract Background Resistance to β-lactams amongst PSA is common with roughly 20% of isolates demonstrating resistance TZP. This can lead delays in the time appropriate empiric therapy. While rapid diagnostics identify at earlier points, they fail detect β-lactam mechanisms this pathogen. Though risk factors for TZP (TZP-R) have been identified, co-resistance traditional anti-PSA common, so decisions turn other or novel agents presence such predictors are unclear. study aims find unique varying degrees TZP-R inform these decisions. Methods was a retrospective case-case-case-control all non-cystic fibrosis patients isolated from culture 2015-2021 Michigan Medicine. Four groups were created based on susceptibility profile PSA: susceptible (TZP-S), only (TZP-R ONLY), addition 1 2 PLUS), and (pan resistance, PBR). Bivariate multivariate analyses performed compare each degree TZP-S group. Results then compared across models assess uniqueness given resistant phenotype. 2365 included, results listed table. The sole predictor ONLY recent ceftriaxone cefotaxime use. Independent PLUS community acquired infection, ICU residence, exposure aztreonam. Most identified either PBR shared between including history PSA, multiple antibiotics. Multivariate Models ONLY, PLUS, Conclusion analysis demonstrates that previously P. aeruginosa greater resistance. Given findings, consideration needs be escalation isolation, rather than β-lactams. Disclosures Owen Albin, MD, Charles River Laboratory: Advisor/Consultant|Cipla Pharmaceuticals: Advisor/Consultant|Shionogi Inc: Advisor/Consultant Keith S. Kaye, GSK: Advisor/Consultant|merck: Stocks/Bonds|Qpex: Advisor/Consultant|Shionogi: Advisor/Consultant|Spero: jason M. Pogue, PharmD, consultant Venatorx, Merck, Shionogi, QPex Biopharma, Utility, GSK, Entasis.: Advisor/Consultant.