The Correlation Between the Types of Initial Bacterial Infection and Clinical Prognosis in Patients With Septic AKI

BACKGROUND: Acute kidney injury (AKI) is a common complication of sepsis and is an independent risk factor for mortality. It is unclear whether different bacteria play different roles in the occurrence and development of sepsis-associated AKI (S-AKI). We observed the clinical characteristics and outcomes of patients that have types of bacterial infection, and different infections sites before the occurrence of AKI, respectively. METHODS: Data of patients who were diagnosed with sepsis and later developed AKI from 2008 to 2019 were retrieved from the MIMIC-IV 1.0 database. Patients were first divided into the two groups according to the bacterial culture results obtained prior to AKI occurrence: bacterial cultured positive (N = 1,785) and bacterial cultured negative (N = 8,777). Patients with bacteria culture positive were divided into culture bacteria Gram-positive (CGP, N = 1248) and Gram-negative (CGN, N = 537) groups. RESULTS: Overall, 1,785 patients were included in the present analysis. The patients in CGN group were older (70 vs. 66, p < 0.001), had lower body mass index (BMI) (27.0 vs. 28.4, p < 0.001), higher acute physiology III (APS III) score (63.0 vs. 58, p = 0.001), shorter time from positive microbial culture to diagnosis of AKI (2.94 vs. 3.16 days, p = 0.013) and longer intensive care unit (ICU) stay time (5.94 vs. 4.77 days, p < 0.001) compared with those in the CGP group (n = 1,248). In the culture gram-negative bacteria in patients with positive blood cultures (CGNb) group, the rate of vasopressors using (73.1 vs. 56.4%, P = 0.007), the Sequential Organ Failure Assessment (SOFA) score (10 vs. 9, p = 0.005), and the level of lactate (3.7 vs. 2.5, p = 0.001) were higher than those in the culture gram-positive bacteria in patients with positive blood cultures (CGPb) group. The time from positive microbial culture to the diagnosis of AKI was shorter (2.23 vs. 3 days, p = 0.001) in the CGNb group. However, there was no significant difference in the continuous renal replacement treatment (CRRT) application or short-term mortality rates between CGN and CGP groups. CONCLUSION: The Gram types of bacteria cultured prior to S-AKI occurrence was not related to AKI stage, CRRT application, and short-term mortality. Compared with the Gram-positive bacterial infections, Gram-negative bacterial infections take a shorter time to develop into AKI, and had a higher disease severity score.