187. Risk Factors and Outcomes of Patients with Serratia Bacteremia at an Academic Medical Center

Abstract

Abstract Background The majority of reported Serratia infective endocarditis (SIE) in recent years are healthcare-associated. At our urban institution with a high prevalence of people who inject drugs (PWID), we noted an increasing number of Serratia bacteremias (SB) and SIE over the past decade. Our study describes patient factors associated with SB and SIE. Methods We evaluated charts of patients with SB at our institution between 2010 and 2022 to determine risk factors and clinical outcomes. Results There were 157 episodes of SB in 153 patients. The majority were male (57%), white (57%) with a mean age 53. The most common source of infection was catheter- line-associated infection (CLABSI) (27%), followed by primary bacteremia (19%). Twenty-six % were PWID with younger mean age (41 years). PWID had lower mortality than non-PWID (23% vs 44%, p=0.023). Sixty-nine (46%) were admitted to the intensive care unit (ICU) with significantly higher mortality associated with ICU admission (48% vs 8%, p=0.015). Echocardiograms were performed in 59% (93/157) of SB episodes and 14% had SIE (13/93). Most SIE (69%) occurred after 2017 with 89% in PWID (8/9). The most common comorbidity with SIE was injection drug use (IDU) (69%). All non-IDU SIE were CLABSI-related; 75% had hemodialysis catheters. Tricuspid valves were infected in 46%. Sixty-two % of those with SIE had septic emboli. Most SIE (69%) required ICU admission. Overall mortality was 31%. Only 2% (3/153) of patients with SB developed antibiotic resistance on therapy. Clinical worsening or failure occurred in 20% (32/157). Only 5% (7/157) had microbiologic recurrence within 30 days. 32% of discharged patients re-presented to the hospital within 30 days. Almost all deaths (92%) occurred during initial admission. Conclusion Patients with SB were quite ill with a high rate of in-hospital mortality; over half of the patients had antibiotic exposures prior to developing SB or presented within 90 days of a prior hospitalization. The majority of SB were line-associated, including all episodes of non-IDU SIE. IDU was the second most common comorbidity and PWID with SB had a higher rate of SIE, with most IDU-associated SIE diagnosed after 2017. This aligns with other recent studies documenting the increased prevalence of SB, especially in PWID. Disclosures Madeline King, PharmD, La Jolla: Advisor/Consultant|Shionogi: Advisor/Consultant