Vancomycin With Concomitant Piperacillin/Tazobactam vs. Cefepime or Meropenem Associated Acute Kidney Injury in General Ward Patients: A Multicenter Propensity Score-Matched Study

Background: Concurrent administration of vancomycin and piperacillin/tazobactam (VAN+PTZ) may increase the risk of acute kidney injury (AKI) in hospitalized patients. Comprehensive characterization of VAN+PTZ associated AKI and recovery patterns remains lacking in previous reports. Objective: To compare the incidence of AKI associated with VAN+PTZ compared to either cefepime (CEF) or meropenem (MER) with VAN in adult general ward patients. Methods: A multicenter, retrospective, propensity score cohort study was conducted in non-critically ill adult patients. Included patients were concurrently administered VAN+PTZ or VAN+CEF/MER. Patients developing AKI ≤48 hours following combination therapy were excluded. The primary endpoint was to compare the incidence of AKI between study groups. Multivariable Cox regression modeling in predicting AKI was also conducted. Results: A total of 3199 patients met inclusion criteria and were evaluated. The incidence of AKI in VAN+PTZ and VAN+CEF/MER groups were 16.4% and 8.7%, respectively (P < .001). The onset to AKI was 1.8 days earlier with VAN+PTZ compared to VAN+CEF/MER (P < .001). Multivariable prediction model showed concomitant VAN+PTZ was identified as an independent risk factor of developing AKI (HR 2.34, 1.82-3.01, P < .001). The VAN+PTZ group experienced significantly higher rates of severe AKI (stage II or III) compared to the VAN+CEF/MER group (P = .002). No differences in the AKI recovery patterns were found between study groups. Conclusions: Concomitant VAN+PTZ in adult general ward patients was independently associated with an increased risk of AKI overall. More severe AKI was also associated with VAN+PTZ.

Comparison of Methicillin-Resistant Staphylococcus aureus Nasal Screening Predictive Value in the Intensive Care Unit and General Ward

BACKGROUND

The clinical utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening appears promising for antimicrobial stewardship programs. However, a paucity of data remains on the diagnostic performance of culture-based MRSA screen in the intensive care unit (ICU) for pneumonia and bacteremia.

OBJECTIVE

The objective of this study was to compare the predictive value of culture-based MRSA nasal screening for pneumonia and bacteremia in ICU and general ward patients.

METHODS

This multicenter, retrospective study was conducted over a 23-month period. Adult patients with MRSA nasal screening ≤48 hours of collecting a respiratory and/or blood culture with concurrent initiation of anti-MRSA therapy were included. The primary endpoint was to compare the negative predictive value (NPV) associated with culture-based MRSA nasal screening between ICU and general ward patients with suspected pneumonia.

RESULTS

A total of 5106 patients representing the ICU (n = 2515) and general ward (n = 2591) were evaluated. The NPV of the MRSA nares for suspected pneumonia was not significantly different between ICU and general ward patient populations (98.3% and 97.6%, respectively; P = 0.41). The MRSA nares screening tool also had a high NPV for suspected bacteremia in ICU (99.8%) and general ward groups (99.7%) (P = 0.56). The overall positive MRSA nares rates in the ICU and general ward patient populations were 9.1% and 8.2%, respectively (P = 0.283). Moreover, MRSA-positive respiratory and blood cultures among ICU patients were 5.8% and 0.8%, respectively.

CONCLUSION AND RELEVANCE

Our findings support the routine use of MRSA nasal screening using the culture-based method in ICU patients with pneumonia. Further research on the clinical performance for MRSA bacteremia in the ICU is warranted.

Performance of Bayesian Area Under the Concentration-Time Curve-Based Pharmacokinetic Dosing Based on a One-Compartment Model and Trough-Only Monitoring for Vancomycin

A novel Bayesian method was developed to interpret serum vancomycin concentrations (SVCs) following the administration of one or more vancomycin doses with potential varying doses and intervals based on superposition principles. The method was evaluated using retrospective data from 442 subjects from three hospitals. The patients were required to receive vancomycin for more than 3 days, have stable renal function (fluctuation in serum creatinine of ≤0.3 mg/dL), and have at least 2 trough concentrations reported. Pharmacokinetic parameters were predicted using the first SVC, and the fitted parameters were then used to predict subsequent SVCs. Using only covariate-adjusted population prior estimates, the first two SVC prediction errors were 47.3 to 54.7% for the scaled mean absolute error (sMAE) and 62.1 to 67.8% for the scaled root mean squared error (sRMSE). "Scaled" refers to the division of the MAE or RMSE by the mean value. The Bayesian method had minimal errors for the first SVC (by design), and for the second SVC, the sMAE was 8.95%, and the sRMSE was 36.5%. The predictive performance of the Bayesian method did degrade with subsequent SVCs, which we attributed to time-dependent pharmacokinetics. The 24-h area under the concentration-time curve (AUC) was determined from simulated concentrations before and after the first SVC was reported. Prior to the first SVC, 170 (38.4%) patients had a 24-h AUC of <400 mg · h/L, 186 (42.1%) had a 24-h AUC within the target range, and 86 (19.5%) had a 24-h AUC of >600 mg · h/L. After the first SVC was reported, 322 (72.9%) had a 24-h AUC within the target range, 68 (15.4%) had low values, and 52 (11.8%) had high values based on the model simulation. Target attainments were 38% before the first SVC and 73% after the first SVC. The hospitals had no policies or procedures in place for targeting 24-h AUCs, although the trough target was typically 13 to 17 mg/L. Our data provide evidence of time-dependent pharmacokinetics, which will require regular therapeutic drug monitoring regardless of the method used to interpret SVCs.

667. Real-world Experience of Cefiderocol with Pseudomonas aeruginosa in the PROVE (Retrospective Cefiderocol Chart Review) Study

Background

Gram-negative (GN) bacterial resistance is an urgent global health problem. Cefiderocol (CFDC) is active against many resistant GN pathogens, including Pseudomonas aeruginosa (PA). PROVE is an ongoing international, retrospective study assessment of CFDC use for Gram-negative infections (GNI).

Methods

Patients were eligible if they received ≥ 72 hours of CFDC. Patient and pathogen characteristics, hospital course, and antibiotic treatment patterns were described. All-cause mortality (ACM) at 14 and 30 days and clinical cure were examined as outcomes, overall, and by key characteristics such as pathogen susceptibility (determined at the local level), patient demographics, infection site, and severity of illness. Serious adverse drug reactions (SADR) were recorded.

Results

To date, 123 patients treated with CFDC at 12 sites were included. Sixty-five patients had PA as a pathogen, either alone (N=45) or in combination with another pathogen (N=20) attributed to starting CFDC. The median age was 54 years; 68% were male. The most prevalent comorbidity was diabetes with end stage organ damage (N=15, 23%). CFDC was given in an ICU setting in 54 (82%) patients. Vasopressors and mechanical ventilation were required in 42% and 62%, respectively. Most (91%) PA were carbapenem resistant. The median time from a positive culture to start of CFDC was 6 days. CFDC monotherapy was used in 75%. The most common GN antibiotic class used concurrently with CFDC was aminoglycosides (N=7). Targeted therapy with CFDC against pathogens of known susceptibility with or without prior GN antibiotics accounted for 80% of use. The remainder was used for salvage (15%) or empirically (2%). Susceptibility testing to CFDC, available for 54 cultures (54 patients), showed 94% (51/54) were susceptible. Post-CFDC initiation 14- and 30-day all-cause mortality (ACM) was 9% (95% CI: 3%-19%) and 23% (95% CI: 14%-35%) respectively. Clinical resolution was achieved in 66% (95% CI: 53% -77%). Thirty-day ACM for susceptible pathogens was 25% (13/51).

Cefiderocol Use Patterns in Pseudomonas aeruginosa

Conclusion

Real-world use of CFDC for PA demonstrated that most patients had multiple comorbidities and were severely ill. These data suggest that CFDC is being used appropriately with little empirical use in patients with few treatment options.

Disclosures

Stephen Marcella, MD, MPH, Shionogi: Shionogi employee|Shionogi, Inc: Employee Amy L. Carr, PharmD, BCIDP, Shionogi: Advisory Board Sean Nguyen, n/a, Shionogi: Employee Anan Zhou, MPH, Shionogi, Inc: contracting work for Shionogi, Inc.

666. Outcomes Using Cefiderocol for the Treatment of Acinetobacter baumannii Infections from the PROVE (Real-World Evidence) Study

Background

PROVE is an ongoing international, retrospective study assessing cefiderocol (CFDC) for Gram-negative (GN) infections. Carbapenem-resistant Acinetobacter baumannii (CRAB) infections are difficult-to-treat with limited treatment options. CFDC is a novel sidero cephalosporin with activity against CRAB. This analysis describes the outcomes and treatment patterns of CFDC treatment in CRAB infections from this study.

Methods

Patients were eligible if they received ≥ 72 hours of CFDC. Key patient characteristics, infecting pathogen susceptibility, illness severity, and treatment patterns were assessed. Fourteen and 30-day all-cause mortality (ACM) and clinical cure were examined as outcomes. Susceptibility testing was performed locally. Serious adverse drug reactions (SADR) were recorded.

Results

To date,123 patients treated with CFDC at 12 sites were included. Forty-one had monomicrobial (n=29) or polymicrobial (n=12) Acinetobacter baumannii (AB) infection. All but one were CRAB. The median age was 53 years; 71% were male. The most prevalent comorbidity was severe burns (N=9, 22%). Sixty-one percent of patients received CFDC in the ICU, 51% required mechanical ventilation, and 34% required vasopressor support. The median time from positive culture to CFDC initiation was 5 days. CFDC monotherapy was used in 61%. Tetracyclines were the most common concurrent GN antibiotics used with CFDC (N = 8, 19.5%). Targeted therapy with or without prior GN antibiotics was used in 76%, salvage in 20%, and empirical in 2%. Susceptibility results were available for 28 AB cultures from 28 patients of which 82% were susceptible to CFDC. Post-CFDC 14- and 30-day ACM was 12% (95% CI: 4%-26%) and 22% (95% CI: 11%-38%), respectively. Clinical resolution was achieved in 59% (95% CI: 42% -74%). Thirty-day ACM varied by susceptibility to CFDC: 26% for susceptible, 40% for resistant. One SADR (interstitial nephritis) was reported.

Cefiderocol Use Patterns in Acinetobacter baumannii

Conclusion

Real-world use of CFDC for AB demonstrates that most patients were complex with multiple comorbidities and severe illness prior to treatment. It was used mostly as targeted therapy. CFDC may be a treatment option in these difficult-to-treat infections.

Disclosures

Stephen Marcella, MD, MPH, Shionogi: Shionogi employee|Shionogi, Inc: Employee Amy L. Carr, PharmD, BCIDP, Shionogi: Advisory Board Benjamin Georgiades, PharmD, Shionogi, Inc: Employee Caroline Margiotta, MA, Shionogi, Inc: contracting work for Shionogi, Inc.

Vancomycin with concomitant piperacillin/tazobactam vs. cefepime or meropenem associated acute kidney injury in the critically ill: A multicenter propensity score-matched study

PURPOSE

The risk of acute kidney injury (AKI) associated with concomitant vancomycin and piperacillin/tazobactam in the intensive care unit (ICU) remains controversial. The aim of this study was to compare the AKI incidence associated with concomitant vancomycin and piperacillin/tazobactam compared to either cefepime or meropenem with vancomycin in the ICU.

MATERIALS AND METHODS

A multicenter, retrospective, propensity score-matched cohort study was conducted in adult ICU patients administered vancomycin in combination with either piperacillin/tazobactam, cefepime, or meropenem were included. Patients developing AKI ≤48 h following combination therapy initiation were excluded. The primary endpoint was to compare the incidence of AKI associated with concomitant antimicrobial therapy. Multivariable Cox regression modeling in predicting AKI was also conducted.

RESULTS

A total of 1044 patients were matched. The AKI incidence in vancomycin- piperacillin/tazobactam and vancomycin-cefepime/meropenem groups were 21.9% and 16.8%, respectively (p = 0.068). Multivariable prediction models showed concomitant vancomycin-piperacillin/tazobactam was an independent risk factor of AKI using serum creatinine only (HR 1.52, 1.10-2.10, p = 0.011) and serum creatinine with urine output-based KDIGO criteria (HR 1.77, 1.18-2.67, p = 0.006). No significant differences between groups were observed for AKI recovery patterns or mortality.

CONCLUSION

Concomitant vancomycin and piperacillin/tazobactam administration in adult ICU patients was independently associated with an increased risk of AKI.

Cefiderocol Pharmacokinetics in a Patient Receiving Continuous Venovenous Hemodiafiltration

Antimicrobial dosing in patients receiving continuous renal replacement therapy is a continued clinical challenge. We describe a case of a patient receiving cefiderocol 2 g intravenously every 8 hours as a 3-hour infusion for a multidrug-resistant Pseudomonas aeruginosa pneumonia and bacteremia while undergoing continuous venovenous hemodiafiltration. The clinical course and cefiderocol pharmacokinetics are described.