P-857. Serratia Bacteremia: Risk Factors, Complications and Outcomes
Authors: Monardo Roberta , Park Larry , Ruffin Felicia , Korn Rachel E , Farahani Parisa , Castagna Antonella , Ripa Marco , Fowler Vance G , Thaden Joshua T , Maskarinec Stacey 
Published: January 2025

Abstract

Background
Previously considered a rare opportunistic pathogen, Serratia is now an emerging cause of bacteremia. However, the demographics and outcomes of patients with Serratia bacteremia remain poorly understood. We thus compared the risk factors and outcomes of patients with Serratia bacteremia relative to other Enterobacterales species in a prospectively ascertained cohort of hospitalized patients.
Rates of device infection in patients with medical devices.
Rates of device infection in patients with medical devices stratified by device type. P values ≤0.05 are considered statistically significant and indicated (*).

Methods
Patients with gram-negative bacteremia (GNB) were prospectively enrolled from 2002-2021 at Duke University. Clinical characteristics and outcomes were compared among patients with bacteremia due to Serratia and other Enterobacterales. Multivariable logistic regression models were used to determine features independently associated with outcomes.
Risk factors associated with device-associated infection.
Risk factors associated with device-associated infection. The multivariable models of factors associated with underlying device infection in patients with any medical device (A) and only cardiac devices (B) and gram-negative bacteremia are shown. P values ≤0.05 are considered statistically significant and indicated (*).

Results
Among 2676 patients with GNB, 173 (6.5%) had Serratia bacteremia. Patients with Serratia bacteremia, relative to GNB caused by other Enterobacterales, were more likely to have a medical device (59% vs 35.6%; P&lt; 0.001), device-associated infection (42.2% vs. 21.3%, P&lt; 0.001), and persistent bacteremia (23.2% vs. 12.9%; P&lt; 0.001). Among all patients with a medical device (n = 993; 37.1%), Serratia was associated with an increased risk of any device infection in an adjusted model (odds ratio (OR) 2.031; 95% confidence interval (CI), 1.234-3.343). The risk for device infection was highest among patients with cardiac devices (OR 3.947, 95% CI 1.449-10.751).

Conclusion
Compared to patients with GNB due to other Enterobacterales, patients with Serratia bacteremia were more likely to have a device infection in general, a cardiac device-associated infection in particular, and persistent bacteremia.

Disclosures
Antonella Castagna, MD, Bristol-Myers Squibb: Advisor/Consultant|Gilead Sciences, Inc.: Advisor/Consultant|Gilead Sciences, Inc.: Grant/Research Support|Gilead Sciences, Inc.: Honoraria|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Janssen: Honoraria|Merck Sharp & Dohme: Advisor/Consultant|Merck Sharp & Dohme: Grant/Research Support|Merck Sharp & Dohme: Honoraria|ViiV Healthcare: Advisor/Consultant|ViiV Healthcare: Grant/Research Support|ViiV Healthcare: Honoraria Vance G. Fowler, MD, MHS, Affinergy: Advisor/Consultant|ArcBio: Stocks/Bonds (Private Company)|Armata: Advisor/Consultant|Astra Zeneca: Advisor/Consultant|Astra Zeneca: Grant/Research Support|Basilea: Advisor/Consultant|Basilea: Grant/Research Support|ContraFect: Advisor/Consultant|ContraFect: Grant/Research Support|Debiopharm: Advisor/Consultant|Destiny: Advisor/Consultant|EDE: Grant/Research Support|Genentech: Advisor/Consultant|Genentech: Grant/Research Support|GSK: Advisor/Consultant|Janssen: Advisor/Consultant|Karius: Grant/Research Support|MedImmune: Grant/Research Support|Merck: Grant/Research Support|sepsis diagnostics: Patent pending|UptoDate: Royalties|Valanbuio: Stocks/Bonds (Private Company)|Valanbuio: Stocks/Bonds (Private Company) Joshua T. Thaden, MD, PhD, National Institutes of Health K08 AI171183 (Thaden): Grant/Research Support Stacey Maskarinec, MD, PHD, National Institutes of Health K23 HL159275 (Maskarinec): Grant/Research Support