P-819. Epidemiology of <i>Serratia marcescens</i> Bloodstream Infections in a Hospital System in the Southeast U.S

Abstract Background Serratia marcescens (Sm) is an environmental gram-negative bacilli that can cause a variety of serious human infections. Sm is frequently attributed as a hospital acquired infection. However, there is not extensive documentation as to the common etiologies of Serratia bloodstream infections (BSI), frequency of antibiotic resistance, and risk factors for recurrent infection or mortality. Methods We conducted a retrospective chart review of a cohort of patients (pts) ≥ 18 years old with Serratia marcescens BSI from 5/2016 to 10/2022 at our hospital system. Sm BSI was defined as ≥ 1 blood culture positive for Sm. Multidrug resistance was defined according to Centers for Disease Control (CDC) criteria. Patients were assessed for outcomes of recurrence of bacteremia (positive blood culture with same isolate within 3 months of clearance) and 30-day mortality. Results A total of 243 patients had Sm BSI during the study period. The most frequent etiology was central line-associated BSI (38%) followed by skin and soft tissue infection (12%). The majority (96%) of isolates were not multidrug resistant. Most patients had a repeat blood culture (67%), and of these patients, 15% had recurrence of bacteremia. A total of 44 patients (18%) died within 30 days. Echocardiogram was performed in 60% of our patients, with 7 patients diagnosed as having endocarditis or device endocarditis. Current active or history of injection drug use occurred in 7.5% of patients. Conclusion Our retrospective study demonstrates a low burden of antibiotic resistance in Sm at our hospital system. Similar to prior studies, CLABSI is a frequent cause of Sm BSI, and foreign materials/devices are common in patients with Sm BSI. Our patient population has a lower rate of IVDU compared to other studies of Sm BSI, and endocarditis is not common. Further analysis is needed to evaluate treatment regimens and other risk factors for recurrent BSI and mortality. Disclosures All Authors: No reported disclosures