1681: Evaluating Clinical Outcomes of Gram-Negative Bacteremia and Presence of Id Consult

Introduction: Gram-negative bloodstream infections (GN-BSIs) are associated with significant morbidity and mortality, especially with the rising incidence of multidrug-resistant organisms. While infectious diseases (ID) consultation has demonstrated improved outcomes in gram-positive infections, its impact in GN-BSIs is less well established. This study aimed to describe the treatment patterns, clinical outcomes, and role of ID consultation in patients with GN-BSI at a large academic center. Methods: This retrospective cohort study included adult and pediatric patients with first episodes of monomicrobial aerobic GN-BSI across three University of Kentucky hospitals from July 1, 2022, to December 31, 2024. Demographic data, clinical variables, microbiologic results, antimicrobial therapy, and ID consultation status were collected. The primary outcome was 30-day all-cause mortality. Statistical analyses included chi-square tests, t-tests, and CART modeling. Results: Among 970 patients with GN-BSI, 416 (42.9%) were admitted to the ICU. These patients had a median age of 61.5 years and BMI of 27.3. The median hospital length of stay was 18.5 days, with a median ICU stay of 7.1 days. Just over half were male (54.3%), and 50% of the infections were community-acquired. The overall ICU mortality rate was 26.4%. Only 37.3% of ICU patients received an ID consultation. Although not statistically significant, ID consultation was associated with a lower mortality rate (21.3% vs 29.5%, p=0.066). E. coli was the most common pathogen (35.8%), followed by K. pneumoniae (16.6%) and P. aeruginosa (12.3%). Resistance testing identified CTX-M in 9.1% of isolates, with only one case of VIM detected. Mortality varied notably by organism, highest with P. aeruginosa (43.1%) and S. marcescens (40.7%), and lowest with E. cloacae (12.0%). Higher mortality was strongly associated with elevated qPITT, CCI, and SOFA scores (p< 0.001). Conclusions: GN-BSIs in critically ill patients are associated with substantial mortality, particularly in infections caused by P. aeruginosa and S. marcescens. ID consultation was associated with lower mortality, although this finding did not reach statistical significance. These results support the potential role of ID involvement in improving outcomes for patients with GN-BSIs.