Optimal Empiric Polymyxin B Treatment of Patients Infected with Gram-Negative Organisms Detected Using a Blood Antimicrobial Surveillance Network in China

Prevention and management of antibiotic associated acute kidney injury in critically ill patients: new insights

PURPOSE OF REVIEW

Drug associated kidney injury (D-AKI) occurs in 19-26% of hospitalized patients and ranks as the third to fifth leading cause of acute kidney injury (AKI) in the intensive care unit (ICU). Given the high use of antimicrobials in the ICU and the emergence of new resistant organisms, the implementation of preventive measures to reduce the incidence of D-AKI has become increasingly important.

RECENT FINDINGS

Artificial intelligence is showcasing its capabilities in early recognition of at-risk patients for acquiring AKI. Furthermore, novel synthetic medications and formulations have demonstrated reduced nephrotoxicity compared to their traditional counterparts in animal models and/or limited clinical evaluations, offering promise in the prevention of D-AKI. Nephroprotective antioxidant agents have had limited translation from animal studies to clinical practice. The control of modifiable risk factors remains pivotal in avoiding D-AKI.

SUMMARY

The use of both old and new antimicrobials is increasingly important in combating the rise of resistant organisms. Advances in technology, such as artificial intelligence, and alternative formulations of traditional antimicrobials offer promise in reducing the incidence of D-AKI, while antioxidant medications may aid in minimizing nephrotoxicity. However, maintaining haemodynamic stability using isotonic fluids, drug monitoring, and reducing nephrotoxic burden combined with vigilant antimicrobial stewardship remain the core preventive measures for mitigating D-AKI while optimizing effective antimicrobial therapy.

Polymyxin B therapy based on therapeutic drug monitoring in carbapenem-resistant organisms sepsis: the PMB-CROS randomized clinical trial

BACKGROUND

The appropriate administration regimen of polymyxin B is yet controversial. The present study aimed to explore the optimal dose of polymyxin B under therapeutic drug monitoring (TDM) guidance.

METHODS

In China's Henan province, 26 hospitals participated in a randomized controlled trial. We included patients with sepsis caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) susceptible to polymyxin B. The patients were randomly divided into a high-dose (HD) group or a low-dose (LD) group and received 150 mg loading dose, 75 mg every 12 h and 100 mg loading dose, 50 mg every 12 h, respectively. TDM was employed to determine if the dose of polymyxin B needs adjustment based on the area under the concentration-time curve across 24 h at a steady state (ssAUC0-24) of 50-100 mg h/L. The primary outcome was the 14-day clinical response, and the secondary outcomes included 28- and 14-day mortality.

RESULTS

This trial included 311 patients, with 152 assigned to the HD group and 159 assigned to the LD group. Intention-to-treat analysis showed that the 14-day clinical response was non-significant (p = 0.527): 95/152 (62.5%) in the HD group and 95/159 (59.7%) in the LD group. Kaplan-Meier's 180-day survival curve showed survival advantage in the HD group than in the LD group (p = 0.037). More patients achieved the target ssAUC0-24 in the HD than in the LD group (63.8% vs. 38.9%; p = 0.005) and in the septic shock subgroup compared to all subjects (HD group: 71.4% vs. 63.8%, p = 0.037; LD group: 58.3% vs. 38.9%, p = 0.0005). Also, the target AUC compliance was not correlated with clinical outcomes but with acute kidney injury (AKI) (p = 0.019). Adverse events did not differ between the HD and LD groups.

CONCLUSION

A fixed polymyxin B loading dose of 150 mg and a maintenance dose of 75 mg every 12 h was safe for patients with sepsis caused by CR-GNB and improves long-term survival. The increased AUC was associated with increased incidence of AKI, and TDM results were valued to prevent AKI. Trial registration Trial registration ClinicalTrials.gov: ChiCTR2100043208, Registration date: January 26, 2021.

Cost-effectiveness analysis of ceftazidime-avibactam as definitive treatment for treatment of carbapenem-resistant Klebsiella pneumoniae bloodstream infection

Background

Ceftazidime-avibactam (CAZ-AVI) is a novel antibiotic that has been confirmed in the United States and China for use in patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI). However, the cost-effectiveness of CAZ-AVI is unknown in China. This study aimed to evaluate the cost-effectiveness of CAZ-AVI compared to polymyxin B (PMB) monotherapy or PMB-based therapy for the treatment of CRKP BSI from the Chinese healthcare perspective.

Methods

A hybrid decision tree and Markov model were constructed for a hypothetical cohort of patients with CRKP BSI. The time horizon of the Markov model was 5 years with an annual discount rate of 5% used in both costs and quality-adjusted life-years (QALYs). The model data was derived from published literature and publicly available database. Regimens with an incremental cost-effectiveness ratio (ICER) lower than the willingness-to-pay (WTP) threshold of $ 11,600 per QALY were considered cost-effective. Deterministic and probabilistic sensitivity analyses were performed to examine the robustness of model analysis.

Results

In the base-analysis, CAZ-AVI provided an additional 60 QALYs and reduced the cost by $ 2,218,300, yielding an ICER of $ -36,730.9/QALY, well below the WTP threshold of $ 11,600 per QALY when compared with PMB-based therapy. CAZ-AVI provided an additional 350 QALYs and increased the cost of $ 208,400, producing an ICER of $ 591.7/QALY that was below the WTP threshold compared to PMB monotherapy. At a $ 11,600/QALY threshold, results were sensitive to the cost of PMB-based strategy, the cost of CAZ-AVI strategy, the probability of cure with CAZ-AVI, and the probability of cure with PMB or PMB-based therapy. CAZ-AVI was an optimal regimen in 76.9% and 80.8% of 10,000 Monte Carlo simulations at $ 11,600/QALY and $ 34,800/QALY, respectively. Meanwhile, CAZ-AVI was cost-effective at the WTP thresholds of all 31 Chinese provinces in 61.4% (Gansu) to 83.1% (Beijing) of simulations.

Conclusions

Ceftazidime-avibactam is expected to be a cost-effective treatment compared with PMB monotherapy or PMB-based therapy for CRKP BSI from the Chinese healthcare perspective.

Pharmacokinetic/Pharmacodynamic Based Breakpoints of Polymyxin B for Bloodstream Infections Caused by Multidrug-Resistant Gram-Negative Pathogens

The latest PK/PD findings have demonstrated negligible efficacy of intravenous polymyxins against pulmonary infections. We investigated pharmacokinetic/pharmacodynamic (PK/PD)-based breakpoints of polymyxin B for bloodstream infections and the rationality of the recent withdrawal of polymyxin susceptibility breakpoints by the CLSI. Polymyxin B pharmacokinetic data were obtained from a phase I clinical trial in healthy Chinese subjects and population pharmacokinetic parameters were employed to determine the exposure of polymyxin B at steady state. MICs of 1,431 recent clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae collected from across China were determined. Monte-Carlo simulations were performed for various dosing regimens (0.42–1.5 mg/kg/12 h via 1 or 2-h infusion). The probability of target attainment, PK/PD breakpoints and cumulative fraction of response were determined for each bacterial species. MIC₉₀ of polymyxin B was 1 mg/L for P. aeruginosa and 0.5 mg/L for A. baumannii and K. pneumoniae. With the recommended polymyxin B dose of 1.5–2.5 mg/kg/day, the PK/PD susceptible breakpoints for P. aeruginosa, A. baumannii and K. pneumoniae were 2, 1 and 1 mg/L respectively for bloodstream infection. For Chinese patients, polymyxin B dosing regimens of 0.75–1.5 mg/kg/12 h for P. aeruginosa and 1–1.5 mg/kg/12 h for A. baumannii and K. pneumoniae were appropriate. Breakpoint determination should consider the antimicrobial PK/PD at infection site and delivery route. The recent withdrawal of polymyxin susceptible breakpoint by CLSI primarily based on poor efficacy against lung infections needs to be reconsidered for bloodstream infections.