Flucloxacillin worsens while imipenem-cilastatin protects against vancomycin-induced kidney injury in a translational rat model

Comparison of piperacillin-tazobactam and vancomycin (TZP-VAN) with piperacillin-tazobactam and teicoplanin (TZP-TEI) for the risk of acute kidney injury (CONCOMITANT): A prospective observational, multinational, multi-centre cohort study

OBJECTIVE

Both vancomycin (VAN) and teicoplanin (TEI) augment the risk of acute kidney injury (AKI) when combined with piperacillin-tazobactam (TZP). We aimed to compare the risk of AKI among patients receiving TZP-VAN vs. TZP-TEI.

METHODS

This was a prospective, multinational, multicentre cohort study conducted in 12 centres from Turkiye, Italy, and Spain between 1 June 2022, and 31 December 2023. The primary outcome was the occurrence of AKI between the first day of antibiotic treatment and the third day after completing therapy, according to the Kidney Disease Improving Global Outcomes criteria. Multivariable logistic regression and propensity-score match analyses were employed to adjust for confounding variables. Stratified Kaplan-Meier analysis was used to assess the time-to-AKI between the comparison groups.

RESULTS

Of 187 patients (TZP-TEI, n = 102; TZP-VAN, n = 85), the AKI occurred in 21 patients (24.7%) who received TZP-VAN and in 15 patients (14.7%) with TZP-TEI (unadjusted odds ratio [OR], 1.90; 95% CI: 0.91-3.97; P = 0.087). After adjusting for confounding variables with multivariable analysis, TZP-VAN was not associated with increased odds of AKI compared with TZP-TEI; with an adjusted OR of 2.24 (95% CI: 0.78-6.42; P = 0.133). In propensity-score matched analysis (n = 49 pairs), the AKI risk was similar between the two groups (OR, 2.10; 95% CI: 0.67-6.50; P = 0.199). The stratified Kaplan-Meier analysis indicated no difference between the treatment groups in terms of time-to-AKI (log-rank test, P = 0.107).

CONCLUSIONS

The risk of AKI in TZP-VAN was similar to that in TZP-TEI. These results should be confirmed in randomized controlled trials.

Protamine protects against vancomycin-induced kidney injury

Vancomycin causes kidney injury by accumulating in the proximal tubule, likely mediated by megalin uptake. Protamine is a putative megalin inhibitor that shares binding sites with heparin and is approved for the treatment of heparin overdose. We employed a well-characterized Sprague-Dawley rat model to assess kidney injury and function in animals that received vancomycin, protamine alone, or vancomycin plus protamine over 5 days. Urinary KIM-1 was used as the primary measure for kidney injury, while plasma iohexol clearance was calculated to assess kidney function. Animals had samples drawn pre-treatment in order to serve as their own controls. Additionally, since protamine is not a known nephrotoxin, the protamine group also served as a control. Cellular inhibition studies were performed to assess the ability of protamine to inhibit organic anion transporter (OAT1 and OAT3) and organic cation transporter-2 (OCT2). Rats that received vancomycin alone had significantly increased urinary KIM-1 on day 2 (24.9 ng/24 h, 95% CI 1.87-48.0) compared to the protamine alone group. By day 4, animals that received protamine with their vancomycin had KIM-1 amounts that were elevated compared to protamine alone as a base comparison (KIM-1 29.0 ng/24 h, 95% CI 5.0-53.0). No statistically observed differences were identified for iohexol clearance changes between drug groups or when comparing clearance change from baseline (P > 0.05). No substantial inhibition of OAT1, OAT3, or OCT2 was observed with protamine. IC50 values for protamine were 0.1 mM for OAT1 and OAT3 and 0.043 mM for OCT2. Protamine, when added to vancomycin therapy, delays vancomycin-induced kidney injury as defined by urinary KIM-1 in the rat model by 1-3 days. Protamine putatively acts through the blockade of megalin and does not appear to have significant inhibition on OAT1, OAT3, or OCT2. Since protamine is an approved FDA medication, it has clinical potential as a therapeutic to reduce vancomycin-related kidney injury; however, greater utility may be found by pursuing compounds with fewer adverse event liabilities.

Nut Cracked? Does the ACORN Trial End the Debate Surrounding Vancomycin and Piperacillin-Tazobactam Combination Therapy and Increased Risk for Acute Kidney Injury?

Observational data published over the past decade have suggested that concomitant receipt of piperacillin-tazobactam with vancomycin significantly increases the risk for vancomycin-associated acute kidney injury. Importantly, however, there is significant controversy surrounding this association, and debate continues about the veracity of the risk. Given this ongoing debate, the recently published "Cefepime vs Piperacillin-Tazobactam in Adults Hospitalized With Acute Infection: The ACORN Randomized Clinical Trial" is of tremendous interest to the infectious diseases community. In ACORN, the authors conclude that there was no association between receipt of cefepime or piperacillin-tazobactam and the primary outcome of acute kidney injury or death by day 14, despite the fact that >75% of the population received concomitant vancomycin. In this perspective, we provide a brief history on the controversy, provide a critical analysis of the ACORN findings, and ultimately discuss how these data help inform the ongoing debate.