Comparison between culture-positive and culture-negative septic shock in patients in the emergency department

Culture results of patients with septic shock affect their management strategies, including antibiotic administration. This study aimed to compare clinical characteristics and outcomes of patients with culture-negative septic shock (CNSS) and culture-positive septic shock (CPSS) in the emergency department. We also assessed the differences in duration and de-escalation timing of antibiotic administration between the two groups. This single-center, retrospective, case-control study included adult patients diagnosed with septic shock in the emergency department between January 1, 2019 and March 31, 2020. They were divided into the CNSS and CPSS groups based on their culture results. The baseline characteristics, infection sites, culture types, and clinical outcomes were recorded and compared. Patients with CPSS (63.7%, 311/488) and CNSS (36.3%, 177/488) were identified. The CPSS and CNSS groups had comparable clinical outcomes, including mechanical ventilation (29.6% vs. 32.8%, p = 0.46), renal replacement therapy (19.3% vs. 23.2%, p = 0.31), 30-day mortality (35.7% vs. 36.7%, p = 0.82), and in-hospital mortality (39.5% vs. 41.8%, p = 0.63). The CNSS group had a significantly shorter duration (13 [8 - 19] vs. 16 [10 - 23], days, p = 0.04) and earlier de-escalation timing (5 [2 - 9] vs. 9 [7 - 12], day, p = 0.02) of antibiotic administration than the CPSS group. Patients with CNSS and CPSS had similar clinical characteristics and proportion of adverse outcomes. Physicians can evaluate the feasibility of early de-escalation or discontinuation of antibiotic administration in patients with CNSS showing clinical improvement.