P-846. A Single-Institution Retrospective Analysis on the Administration of Beta-lactam Antibiotics Prior to Vancomycin in Bacteremic Patients

Abstract Background According to the 2021 IDSA Surviving Sepsis Guidelines, prompt administration of antibiotics is an essential recommendation for patients with bacteremia. Similarly to a recent study published by Amoah et al., we sought to determine if the sequence of antibiotic administration impacted 30-day mortality. Methods We conducted a single-institution retrospective study at Baylor Scott & White Medical Center in Temple, Texas, on patients greater than 18 years of age admitted with sepsis and confirmed bacteremia from January 1st, 2021, to July 1st, 2023 who received sequential antibiotic administration with a Beta-lactam and vancomycin within the first 6 hours of admission time. Our primary endpoint was odds ratio for 30-day mortality. Results Of 6143 patients generated from electronic search, 222 patients were included in the Beta-lactam first group and 16 were included in the vancomycin first group. Of these 238 patients, 132 patients were admitted to the ICU upon admission. The most common Beta-lactam antibiotic administered was piperacillin-tazobactam (58.40%) followed by Cefepime (25.47%), then Ceftriaxone (13.03%). For patients with monomicrobial bacteremia, the most common organisms isolated were Escherichia coli (25.21%), Methicillin resistant Staphylococcus aureus (MRSA) (13.45%), Methicillin sensitive Staphylococcus aureus (MSSA) (11.34%), and Proteus mirabilis (7.56%). The calculated odds ratio for 30-day mortality was 0.40 (95% CI 0.089-1.831), indicating a decreased occurrence of mortality within 30 days for patients who received Beta-lactam antibiotics first, though this result was not statistically significant due to limited sample size, particularly within the vancomycin first group. Conclusion Although not statistically significant, our results suggest that prompt administration of Beta-lactam antibiotics prior to vancomycin may have mortality benefit in patients with bacteremia. Further confirmatory studies will be required to investigate this principle. Disclosures All Authors: No reported disclosures