Introduction:
Acute kidney injury (AKI) is a potential complication of systemic infection. Optimising antimicrobial dosing in this dynamic state can be challenging with sub- or supra-therapeutic dosing risking treatment failure or toxicity, respectively. Locally, unadjusted renal dosing for the first 48 hours of infection is recommended; this analysis aims to determine the outcomes associated with this dosing strategy.

Methods:
A retrospective cohort analysis was undertaken in patients treated for Gram-negative bacteraemia with concurrent non-filtration dependent AKI from a single-centre NHS acute hospital (April 2016-March 2020). Patient demographics, microbiology data, antimicrobial treatment and patient outcome (in-hospital mortality, and kidney function) were analysed.

Results:
647 episodes of Gram-negative bacteraemia (608 patients) were included; 305/608(50.2%) were male with median age 71years(range 18–100years). AKI was present in 235/647(36.3%); 78/647(12.1%) and 45/647(7.0%) having Kidney Disease Improving Global Outcomes (KDIGO)-defined injury(stage 2) or failure(stage 3), respectively. In-hospital 30-day mortality was 25/352(7.1%), 14/112(12.5%), 26/123(21.1%) and 11/60(18.3%) in patients with normal renal function, AKI stage 1, AKI stage ≥2 and established CKD, respectively. Recovery of renal function at day21 or discharge was present in 105/106 surviving patients presenting with AKI≥2. Time to recovery of AKI was similar in patients receiving full, low or no aminoglycoside (3days versus4days versus 3days, p=0.612) and those receiving full and low-dose beta-lactam (3days versus 5days, p=0.077).

Conclusion:
There is a high burden of AKI in patients with Gram-negative bacteraemia. Dose adjustments of beta-lactams may not be necessary in the first 48-hours of infection-induced AKI and single-dose aminoglycosides may be considered for early empiric coverage.