Continuous Infusion Versus Intermittent Bolus of Beta-Lactams in Critically Ill Patients with Respiratory Infections: A Systematic Review and Meta-analysis

A Systematic Review of the Pharmacokinetics and Pharmacodynamics of Novel Beta-Lactams and Beta-Lactam with Beta-Lactamase Inhibitor Combinations for the Treatment of Pneumonia Caused by Carbapenem-Resistant Gram-Negative Bacteria

BACKGROUND

Novel beta-lactams show activity against many multidrug-resistant Gram-negative bacteria that cause severe lung infections. Understanding pharmacokinetic/pharmacodynamic characteristics of these agents may help optimise outcomes in the treatment of pneumonia.

OBJECTIVES

To describe and appraise studies that report pulmonary pharmacokinetic and pharmacodynamic data of cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/cilastatin/relebactam and meropenem/vaborbactam.

METHODS

MEDLINE (PubMed), Embase, Web of Science and Scopus libraries were used for the literature search. Pulmonary population pharmacokinetic and pharmacokinetic/pharmacodynamic studies on adult patients receiving cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/cilastatin/relebactam, and meropenem/vaborbactam published in peer-reviewed journals were included. Two independent authors screened, reviewed and extracted data from included articles. A reporting guideline for clinical pharmacokinetic studies (ClinPK statement) was used for bias assessment. Relevant outcomes were included, such as population pharmacokinetic parameters and probability of target attainment of dosing regimens.

RESULTS

Twenty-four articles were included. There was heterogeneity in study methods and reporting of results, with diversity across studies in adhering to the ClinPK statement checklist. Ceftolozane/tazobactam was the most studied agent. Only two studies collected epithelial lining fluid samples from patients with pneumonia. All the other phase I studies enrolled healthy subjects. Significant population heterogeneity was evident among available population pharmacokinetic models. Probabilities of target attainment rates above 90% using current licensed dosing regiments were reported in most studies.

CONCLUSIONS

Although lung pharmacokinetics was rarely described, this review observed high target attainment using plasma pharmacokinetic data for all novel beta-lactams. Future studies should describe lung pharmacokinetics in patient populations at risk of carbapenem-resistant pathogen infections.

Population pharmacokinetics of flucloxacillin as intermittent bolus infusion in patients with Staphylococcus aureus bloodstream infection

BACKGROUND

Optimal antibiotic dosing for Staphylococcus aureus bloodstream infections (BSI) is still controversial. One reason is inter-individual variation in pharmacokinetics, which may be influenced by various patient-related factors, particularly in critically ill patients.

OBJECTIVES

To describe the population pharmacokinetics (PopPK) of the antibiotic flucloxacillin in patients with S. aureus BSI. Subsequently, we sought to translate the model into a user-friendly app for generating a priori and a posteriori time-concentration curves and dose recommendations to optimize dosing regimens.

METHODS

Total and unbound flucloxacillin concentrations were included from 49 patients from a prospective cohort study conducted during clinical routine, including non-critically ill and critically ill individuals who received intermittent bolus applications. These data were analysed using non-linear mixed-effects modelling.

RESULTS

Most patients (98%) were treated with 2 g of flucloxacillin every 4 h. We developed a joint model that simultaneously described total and unbound concentrations. The model included an allometric effect of glomerular filtration rate on clearance and albumin on the albumin dissociation constant. The latter was especially important, as in our population the unbound fraction was higher at 11.5% (16.7% for critically ill patients) compared with reported values of approximately 5%. Based on our joint model, we developed a web-based app for optimizing dosing regimens of flucloxacillin.

CONCLUSIONS

By utilizing data from clinical routine, we were able to create a predictive PopPK model of flucloxacillin and identify influential covariates. The web-based app is currently being validated in a clinical trial.

Usage of Meropenem Continuous Infusion for Treatment of Infectious Complications in Orthopedic Elderly Patients with Anemia: A Case Series

Background and Objectives: The prolonged infusion of meropenem is recommended by guidelines for the treatment of sepsis. However, studies provide controversial data on the advantages of prolonged infusions over intermittent ones. In our opinion, this can be related to age, which possibly distorts the final data, as older people have age-related characteristics. In our study, we analyzed the ventilatory status, laboratory tests and vital signs of the patient and carried out microbiological cultures. Materials and Methods: This was a prospective single-center case series investigation conducted from June 2022 to June 2023. The objective of this study was to evaluate the effectiveness of continuous infusion in elderly patients with severe infectious complications after orthopedic interventions. The primary endpoints were 28-day survival and the emergence of new multidrug-resistant strains. Secondary endpoints were long-term mortality and length of stay in the ICU. Results: Three patients (median age 65, 100% female) received a continuous infusion of meropenem. Two patients were alive at hospital discharge, and one patient died on the 105th day of hospitalization. Multi-resistant bacteria were observed in one patient. Conclusions: The use of a continuous meropenem infusion in the complex treatment of purulent-septic complications in elderly patients with periprosthetic infection and anemia probably led to clinical improvement in these case reports. However, the emergence of new pan-resistant strains and overall mortality using this infusion technique remains unclear. Further, high-quality RCTs for the elderly are needed.

Beta-lactam antibiotic concentrations in critically ill patients with standard and adjusted dosages: A prospective observational study

INTRODUCTION

Antibiotic concentration target attainment is known to be poor in critically ill patients. Dose adjustment is recommended in patients with altered clearance, obesity and those with bacterial species with intermediate susceptibility. The aim of this study was to investigate the variation of antibiotic concentration in critically ill patients with standard or adjusted dosing regimens.

METHODS

The concentration of three beta-lactam antibiotics used in the intensive care unit (ICU) setting, cefotaxime, piperacillin/tazobactam, and meropenem, was measured in patients with confirmed or suspected infection. Mid-dose and trough values were collected during a single dosing interval. The pharmacokinetic endpoints were a free antibiotic concentration that, during the whole dosing interval, was above MIC (100% ƒT > MIC, primary endpoint) or above four times MIC (100% ƒT > 4MIC, secondary endpoint). Non-species related MIC breakpoints were used (1 mg/L for cefotaxime, 8 mg/L for piperacillin/tazobactam, and 2 mg/L for meropenem).

RESULTS

We included 102 patients (38 cefotaxime, 30 piperacillin/tazobactam, and 34 meropenem) at a single ICU, with a median age of 66 years. In total, 73% were males, 40% were obese (BMI ≥30) and the median SAPS 3 score was 63 points. Of all patients, 78 patients (76%) reached the primary endpoint (100%ƒT > MIC), with 74% for cefotaxime, 67% for piperacillin/tazobactam and 88% for meropenem. Target attainment for 100% ƒT > 4MIC was achieved in 40 (39%) patients, overall, with 34% for cefotaxime, 30% for piperacillin/tazobactam and 53% for meropenem. In patients with standard dose 71% attained 100%ƒT > MIC and 37% for 100%ƒT > 4MIC. All patients with reduced dose attained 100%ƒT > MIC and 27% attained 100% ƒT > 4MIC. In patients with increased dose 79% attained 100%ƒT > MIC and 48% 100%ƒT > 4MIC respectively.

CONCLUSIONS

Beta-lactam antibiotics concentration vary widely in critically ill patients. The current standard dosing regimens employed during the study were not sufficient to reach 100% ƒT > MIC in approximately a quarter of the patients. In patients where dose adjustment was performed, the group with increased dose also had low target attainment, as opposed to patients with dose reduction, who all reached target. This suggests the need for further individualization of dosing where therapeutic drug monitoring can be an alternative to further increase target attainment.

Comparing prolonged infusion to intermittent infusion strategies for beta-lactam antibiotics in patients with gram-negative bacterial infections: a systematic review and meta-analysis

INTRODUCTION

Our objective is to determine whether prolonged infusion (PI) of beta-lactam antibiotics yields superior outcomes compared to intermittent infusion (II) in patients with Gram-Negative Bacterial (GNB) infections.

METHODS

We systematically searched papers from PubMed, the Cochrane Library, Embase, and Clinicaltrials.gov, targeting mortality as the primary outcome and looking at the clinical cure rate, hospital and intensive care unit (ICU) stay lengths, antibiotic treatment duration, and mechanical ventilation (MV) duration as secondary outcomes.

RESULTS

Our meta-analysis of 18 studies, including 5 randomized control trials and 13 observational studies, with a total of 3,035 patients-1,510 in the PI group and 1,525 in the II group, revealed significant findings. PI was associated with reduced mortality (RR, 0.67; 95% CI, 0.55-0.81; p = 0.001; I2 = 4.52%) and a shorter MV duration (SMD, -0.76; 95% CI, -1.37 to -0.16; p = 0.01; I2 = 87.81%) compared to II. However, no differences were found in clinical cure rates, antibiotic treatment duration, length of hospital stay, or length of ICU stay.

CONCLUSIONS

The PI approach for administering beta-lactam antibiotics in patients with suspected or confirmed GNB infections may be advantageous in reducing mortality rates and the duration of MV when compared to the II strategy.

Continuous infusion of beta-lactam antibiotics in pediatric intensive care unit: A monocenter before/after implementation study

CONTEXT

Beta-lactam continuous infusion (CI) is currently recommended in adult intensive care units to achieve target concentrations. In pediatric intensive care (PICU), few studies suggest the value of Beta-lactam CI to achieve target concentration. Our objective was to analyze the impact of Beta-lactam CI protocolization on the achievement of target concentration in PICU patients.

MATERIAL AND METHODS

We conducted a single-center retrospective study in patients with beta-lactam treatment for more than 2 days and at least one sample for therapeutic drug monitoring (TDM). From January 2018 to February 2022 (period 1, P1), BL were administered as an intermittent infusion with TDM upon request. From February to September 2022 (period 2, P2), Beta-lactam CI with TDM at day one was protocolized. The primary endpoint concerned achieving fT>4× Minimum Inhibitory Concentration = 100%.

RESULTS

In P1, 214 assays involved 103 patients; in P2, 199 assays involved 72 patients. Target concentration achievement was more frequent in P2 (P2 = 73.7% vs. P1 = 29.1%; p < 0.001). At day 5/6 after Beta-lactam initiation, c-reactive protein concentrations were P1 = 84.9 ± 79.2 mg/L; P2 = 53.7±49.8 mg/L (p < 0.05). In the multivariable logistic regression model: P2, BSA, and albumin were positively associated with target achievement; urea, and male sex were negatively associated with target achievement. The daily average cost of beta-lactam vial consumption per child was: P1 = 5.04 ± 2.6 € vs. P2 = 3.21 ± 2.7 € (p-value < 0.001). The daily average reconstitution time of Beta-lactam syringes per child was: P1 = 23.5 ± 8.7 min, P2 = 13.9 ± 9.2 min (p-value < 0.001).

CONCLUSION

Protocolization of Beta-lactam continuous infusion was associated with more frequent target concentration achievements in PICU. This implementation could be cost-effective and nurse time-saving.

β-Lactam Pharmacokinetic/Pharmacodynamic Target Attainment in Intensive Care Unit Patients: A Prospective, Observational, Cohort Study

BACKGROUND

The aims of this study were to describe pharmacokinetic/pharmacodynamic target attainment in intensive care unit (ICU) patients treated with continuously infused ß-lactam antibiotics, their associated covariates, and the impact of dosage adjustment.

METHODS

This prospective, observational, cohort study was performed in three ICUs. Four ß-lactams were continuously infused, and therapeutic drug monitoring (TDM) was performed at days 1, 4, and 7. The primary pharmacokinetic/pharmacodynamic target was an unbound ß-lactam plasma concentration four times above the bacteria's minimal inhibitory concentration during the whole dosing interval. The demographic and clinical covariates associated with target attainment were evaluated.

RESULTS

A total of 170 patients were included (426 blood samples). The percentages of empirical ß-lactam underdosing at D1 were 66% for cefepime, 43% for cefotaxime, 47% for ceftazidime, and 14% for meropenem. Indexed creatinine clearance was independently associated with treatment underdose if increased (adjusted odds ratio per unit, 1.01; 95% CI, 1.00 to 1.01; p = 0.014) or overdose if decreased (adjusted odds ratio per unit, 0.95; 95% CI, 0.94 to 0.97; p < 0.001). Pharmacokinetic/pharmacodynamic target attainment was significantly increased after ß-lactam dosage adjustment between day 1 and day 4 vs. no adjustment (53.1% vs. 26.2%; p = 0.018).

CONCLUSIONS

This study increases our knowledge on the optimization of ß-lactam therapy in ICU patients. A large inter- and intra-patient variability in plasmatic concentrations was observed, leading to inadequate exposure. A combined indexed creatinine clearance and TDM approach enables adequate dosing for better pharmacokinetic/pharmacodynamic target attainment.

Continuous infusion of beta-lactam antibiotics: narrative review of systematic reviews, and implications for outpatient parenteral antibiotic therapy

INTRODUCTION

Continuous infusion (CI) of beta-lactam antibiotics may be of benefit in some patients, particularly those with severe infections. However, most studies have been small and conflicting results have been reported. The best available evidence on clinical outcomes of beta-lactam CI comes from systematic reviews/meta-analyses that integrate the available data.

AREAS COVERED

A search of PubMed from inception to the end of February 2022 for systematic reviews of clinical outcomes with beta-lactam CI for any indication identified 12 reviews, all of which focused on hospitalized patients, most of whom were critically ill. A narrative overview of these systematic reviews/meta-analyses is provided. No systematic reviews evaluating the use of beta-lactam CI for outpatient parenteral antibiotic therapy (OPAT) were identified, as few studies have focused on this area. Relevant data are summarized, and consideration is given to issues that need to be addressed when using beta-lactam CI in the setting of OPAT.

EXPERT OPINION

Evidence from systematic reviews supports a role for beta-lactam CI in the treatment of hospitalized patients with severe/life-threatening infections. Beta-lactam CI can play a role in patients receiving OPAT for severe chronic/difficult-to-treat infections, but additional data are needed to clarify its optimal use.

Update on Therapeutic Drug Monitoring of Beta-Lactam Antibiotics in Critically Ill Patients—A Narrative Review

Beta-lactam antibiotics remain one of the most preferred groups of antibiotics in critical care due to their excellent safety profiles and their activity against a wide spectrum of pathogens. The cornerstone of appropriate therapy with beta-lactams is to achieve an adequate plasmatic concentration of a given antibiotic, which is derived primarily from the minimum inhibitory concentration (MIC) of the specific pathogen. In a critically ill patient, the plasmatic levels of drugs could be affected by many significant changes in the patient’s physiology, such as hypoalbuminemia, endothelial dysfunction with the leakage of intravascular fluid into interstitial space and acute kidney injury. Predicting antibiotic concentration from models based on non-critically ill populations may be misleading. Therapeutic drug monitoring (TDM) has been shown to be effective in achieving adequate concentrations of many drugs, including beta-lactam antibiotics. Reliable methods, such as high-performance liquid chromatography, provide the accurate testing of a wide range of beta-lactam antibiotics. Long turnaround times remain the main drawback limiting their widespread use, although progress has been made recently in the implementation of different novel methods of antibiotic testing. However, whether the TDM approach can effectively improve clinically relevant patient outcomes must be proved in future clinical trials.

Predictive Factors of Piperacillin Exposure and the Impact on Target Attainment after Continuous Infusion Administration to Critically Ill Patients

Critically ill patients undergo significant pathophysiological changes that affect antibiotic pharmacokinetics. Piperacillin/tazobactam administered by continuous infusion (CI) improves pharmacokinetic/pharmacodynamic (PK/PD) target attainment. This study aimed to characterize piperacillin PK after CI administration of piperacillin/tazobactam in critically ill adult patients with preserved renal function and to determine the empirical optimal dosing regimen. A total of 218 piperacillin concentrations from 106 patients were simultaneously analyzed through the population PK approach. A two-compartment linear model best described the data. Creatinine clearance (CL_CR) estimated by CKD-EPI was the covariate, the most predictive factor of piperacillin clearance (CL) interindividual variability. The mean (relative standard error) parameter estimates for the final model were: CL: 12.0 L/h (6.03%); central and peripheral compartment distribution volumes: 20.7 L (8.94%) and 62.4 L (50.80%), respectively; intercompartmental clearance: 4.8 L/h (26.4%). For the PK/PD target of 100% fT_>1×MIC, 12 g of piperacillin provide a probability of target attainment > 90% for MIC < 16 mg/L, regardless of CL_CR, but higher doses are needed for MIC = 16 mg/L when CL_CR > 100 mL/min. For 100% fT_>4×MIC, the highest dose (24 g/24 h) was not sufficient to ensure adequate exposure, except for MICs of 1 and 4 mg/L. Our model can be used as a support tool for initial dose guidance and during therapeutic drug monitoring.

Beta-lactam exposure and safety in intermittent or continuous infusion in critically ill children: an observational monocenter study

The aim of this study was to assess the pharmacokinetic (PK) exposure and clinical toxicity for three beta-lactams: cefotaxime, piperacillin/tazobactam, and meropenem, depending on two lengths of infusion: continuous and intermittent, in critically ill children. This single center observational prospective study was conducted in a pediatric intensive care unit. All hospitalized children who had one measured plasma concentration of the investigated antibiotics were included. Plasma antibiotic concentrations were interpreted by a pharmacologist, using a Bayesian approach based on previously published population pharmacokinetic models in critically ill children. Exposure was considered optimal, low, or high according to the PK target 100% fT_{> 4 × MIC} and a trough concentration below the toxic concentration (50 mg.L^-1 for cefotaxime, 150 mg.L^-1 for piperacillin, and 44 mg.L^-1 for meropenem). Between May 2019 and January 2020, 80 patients were included and received 106 antibiotic courses: 74 (70%) were administered in intermittent infusion (II) and 32 (30%) in continuous infusion (CI). Compared to II, CI provided more optimal PK exposure (n = 22/32, 69% for CI versus n = 35/74, 47% for II, OR 1.2, 95%CI 1.01-1.5, p = 0.04), less underexposure (n = 4/32, 13% for CI versus n = 36/74, 49% for II, OR 0.7, 95%CI 0.6-0.84, p < 0.001), and more overexposure (n = 6/32, 19% for CI versus n = 3/74, 4% for II, OR 1.2, 95%CI 1.03-1.3, p = 0.01). Five adverse events have been reported during the study period, although none has been attributed to beta-lactam treatment.

CONCLUSION

CI provided a higher probability to attain an optimal PK target compared to II, but also a higher risk for overexposure. Regular therapeutic drug monitoring is recommended in critically ill children receiving beta-lactams, regardless of the length of infusion.

WHAT IS KNOWN

• Since beta-lactams are time-dependent antibiotics, the probability to attain the pharmacokinetic target is higher with continuous infusion compared to that with intermittent infusion. • In daily practice, continuous or extended infusions are rarely used despite recent guidelines, and toxicity is hardly reported.

WHAT IS NEW

• Continuous infusion provided a higher probability to attain an optimal pharmacokinetic target compared to intermittent infusion, but also a higher risk of overexposure. • Regular therapeutic drug monitoring is recommended in critically ill children receiving beta-lactams, regardless of the length of infusion.

Optimizing antibiotic dosing regimens for nosocomial pneumonia: a window of opportunity for pharmacokinetic and pharmacodynamic modeling

INTRODUCTION

Determining antibiotic exposure in the lung and the threshold(s) needed for effective antibacterial killing is paramount during development of new antibiotics for the treatment of nosocomial pneumonia, as these exposures directly affect clinical outcomes and resistance development. The use of pharmacokinetic and pharmacodynamic modeling is recommended by regulatory agencies to evaluate antibiotic pulmonary exposure and optimize dosage regimen selection. This process has been implemented in newer antibiotic development.

AREAS COVERED

This review will discuss the basis for conducting pharmacokinetic and pharmacodynamic studies to support dosage regimen selection and optimization for the treatment of nosocomial pneumonia. Pharmacokinetic/pharmacodynamic data that supported recent hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia indications for ceftolozane/tazobactam, ceftazidime/avibactam, imipenem/cilastatin/relebactam, and cefiderocol will be reviewed.

EXPERT OPINION

Optimal drug development requires the integration of preclinical pharmacodynamic studies, healthy volunteers and ideally patient bronchoalveolar lavage pharmacokinetic studies, Monte-Carlo simulation, and clinical trials. Currently, plasma exposure has been successfully used as a surrogate for lung exposure threshold. Future studies are needed to identify the value of lung pharmacodynamic thresholds in nosocomial pneumonia antibiotic dosage optimization.

Suboptimal Concentrations of Ceftazidime/Avibactam (CAZ-AVI) May Select for CAZ-AVI Resistance in Extensively Drug-Resistant Pseudomonas aeruginosa: In Vivo and In Vitro Evidence

This study correlates in vivo findings in a patient with an extensively drug-resistant (XDR) P. aeruginosa infection who developed resistance to ceftazidime-avibactam (CAZ-AVI) with in vitro results of a 7-day hollow-fiber infection model (HFIM) testing the same bacterial strain. The patient was critically ill with ventilator-associated pneumonia caused by XDR P. aeruginosa ST175 with CAZ-AVI MIC of 6 mg/L and was treated with CAZ-AVI in continuous infusion at doses adjusted for renal function. Plasma concentrations of CAZ-AVI were analyzed on days 3, 7, and 10. In the HIFM, the efficacy of different steady-state concentrations (Css) of CAZ-AVI (12, 18, 30 and 48 mg/L) was evaluated. In both models, a correlation was observed between the decreasing plasma levels of CAZ-AVI and the emergence of resistance. In the HIFM, a Css of 30 and 48 mg/L (corresponding to 5× and 8× MIC) had a bactericidal effect without selecting resistant mutants, whereas a Css of 12 and 18 mg/L (corresponding to 2× and 3× MIC) failed to prevent the emergence of resistance. CAZ/AVI resistance development was caused by the selection of a single ampC mutation in both patient and HFIM. Until further data are available, strategies to achieve plasma CAZ-AVI levels at least 4× MIC could be of interest, particularly in severe and high-inoculum infections caused by XDR P. aeruginosa with high CAZ-AVI MICs.

Stability Studies of 16 Antibiotics for Continuous Infusion in Intensive Care Units and for Performing Outpatient Parenteral Antimicrobial Therapy

The use of continuous infusion to improve the therapeutic efficacy of time-dependent antibiotics has been demonstrated. There is still a lack of data to safely perform these continuous infusions. The objectives in this study were to evaluate the stability by using stability-indicating methods (High-Performance Liquid Chromatography) of 16 antibiotics in concentrated solutions, especially for administration in intensive care units and solutions in elastomeric diffusers at 37 °C for outpatient parenteral antimicrobial therapy. The solutions were considered stable if the percentage of the drug was ≥90%, and the colour and clearness remained unchanged. In syringes, the stability data vary from 4 to 8 h (h) for meropenem in Dextrose 5% (D5W) and Normal Saline (NS), respectively, 6 h for cefotaxime, 12 h for cefoxitin, and 24 h for aztreonam, cefazolin, cefepime, cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam in NS and D5W, and in water for injection for cloxacillin. A stability period of 48 h has been validated for vancomycin (D5W), aztreonam, and piperacillin/tazobactam. Cefoxitin, cefazolin, cefepime, cefotaxime, cloxacillin, and piperacillin are unstable for diffuser administration. In diffusers, stability times vary from 6 h for cefiderocol, 8 h for ceftazidime, 12 h for ceftazidime/avibactam and ceftolozane/tazobactam (NS), 24 h for temocillin (NS) and piperacillin/tazobactam (D5W), up to 48 h for aztreonam and vancomycin. Solutions stored at 37 °C are less stable and allow the administration of seven antibiotics using diffusers.

Modelled target attainment after temocillin treatment in severe pneumonia: systemic and epithelial lining fluid pharmacokinetics of continuous versus intermittent infusions

Objectives: To describe the population pharmacokinetics of temocillin administered via continuous versus intermittent infusion in critically ill patients with pneumonia. Secondary objectives included characterization of epithelial lining fluid (ELF)/plasma penetration ratios and determination of the probability of target attainment (PTA) for a range of MICs. Methods: Thirty-two mechanically ventilated patients who were treated for pneumonia with 6g of temocillin daily for in vitro sensitive pathogens were assigned either to the II (2g every 8h over 0.5h) or to the CI (6g over 24h after a loading dose of 2g) group. A population pharmacokinetic model was developed using unbound plasma and total ELF concentrations of temocillin and related Monte Carlo simulations were performed to assess PTAs. Results: The AUC_0-24 ELF/plasma penetration ratio was 0.73, at steady-state, for both modes of infusion and whatever the level of creatinine clearance. Monte Carlo simulations showed for the minimal pharmacodynamic (PD) targets of 50% T> 1X MIC (II group) and 100% T > 1X MIC (CI group), PK/PD breakpoints of 4 mg/L in plasma and 2 mg/L in ELF and 4mg/L in plasma and ELF, respectively. The breakpoint was 8 mg/L in ELF for both modes of infusion in patients with CL_CR<60mL/min. Conclusion: While CI provides better PKPD indexes, the latter remain below available recommendations for systemic infections, except in case of moderate renal impairment, thereby warranting future clinical studies in order to determine the efficacy of temocillin in severe pneumonia.

Effect of Different Piperacillin-Tazobactam Dosage Regimens on Synergy of the Combination with Tobramycin against Pseudomonas aeruginosa for the Pharmacokinetics of Critically Ill Patients in a Dynamic Infection Model

We evaluated piperacillin-tazobactam and tobramycin regimens against Pseudomonas aeruginosa isolates from critically ill patients. Static-concentration time-kill studies (SCTK) assessed piperacillin-tazobactam and tobramycin monotherapies and combinations against four isolates over 72 h. A 120 h-dynamic in vitro infection model (IVM) investigated isolates Pa1281 (MICpiperacillin 4 mg/L, MICtobramycin 0.5 mg/L) and CR380 (MICpiperacillin 32 mg/L, MICtobramycin 1 mg/L), simulating the pharmacokinetics of: (A) tobramycin 7 mg/kg q24 h (0.5 h-infusions, t1/2 = 3.1 h); (B) piperacillin 4 g q4 h (0.5 h-infusions, t1/2 = 1.5 h); (C) piperacillin 24 g/day, continuous infusion; A + B; A + C. Total and less-susceptible bacteria were determined. SCTK demonstrated synergy of the combination for all isolates. In the IVM, regimens A and B provided initial killing, followed by extensive regrowth by 72 h for both isolates. C provided >4 log10 CFU/mL killing, followed by regrowth close to initial inoculum by 96 h for Pa1281, and suppressed growth to <4 log10 CFU/mL for CR380. A and A + B initially suppressed counts of both isolates to <1 log10 CFU/mL, before regrowth to control or starting inoculum and resistance emergence by 72 h. Overall, the combination including intermittent piperacillin-tazobactam did not provide a benefit over tobramycin monotherapy. A + C, the combination regimen with continuous infusion of piperacillin-tazobactam, provided synergistic killing (counts <1 log10 CFU/mL) of Pa1281 and CR380, and suppressed regrowth to <2 and <4 log10 CFU/mL, respectively, and resistance emergence over 120 h. The shape of the concentration-time curve was important for synergy of the combination.

Guidelines on Implementing Antimicrobial Stewardship Programs in Korea

These guidelines were developed as a part of the 2021 Academic R&D Service Project of the Korea Disease Control and Prevention Agency in response to requests from healthcare professionals in clinical practice for guidance on developing antimicrobial stewardship programs (ASPs). These guidelines were developed by means of a systematic literature review and a summary of recent literature, in which evidence-based intervention methods were used to address key questions about the appropriate use of antimicrobial agents and ASP expansion. These guidelines also provide evidence of the effectiveness of ASPs and describe intervention methods applicable in Korea.

Personalized ß-lactam dosing in patients with coronavirus disease 2019 (COVID-19) and pneumonia: A retrospective analysis on pharmacokinetics and pharmacokinetic target attainment

ABSTRACT

Pathophysiological changes are important risk factors for critically ill patients with pneumonia manifesting sub-therapeutic antibiotic exposures during empirical treatment. The effect of coronavirus disease 2019 (COVID-19) on antibiotic dosing requirements is uncertain. We aimed to determine the effect of COVID-19 on ß-lactam pharmacokinetics (PK) and PK target attainment in critically ill patients with a personalized dosing strategy.Retrospective, single-center analysis of COVID-19 ± critically ill patients with pneumonia (community-acquired pneumonia or hospital-acquired pneumonia) who received continuous infusion of a ß-lactam antibiotic with dosing personalized through dosing software and therapeutic drug monitoring. A therapeutic exposure was defined as serum concentration between (css) 4 to 8 times the EUCAST non-species related breakpoint).Data from 58 patients with pneumonia was analyzed. Nineteen patients were tested COVID-19-positive before the start of the antibiotic therapy for community-acquired pneumonia or hospital-acquired pneumonia. Therapeutic exposure was achieved in 71% of COVID-19 patients (68% considering all patients). All patients demonstrated css above the non-species-related breakpoint. Twenty percent exceeded css above the target range (24% of all patients). The median ß-lactam clearance was 49% compared to ß-lactam clearance in a standard patient without a significant difference regarding antibiotic, time of sampling or present COVID-19 infection. Median daily doses were 50% lower compared to standard bolus dosing.COVID-19 did not significantly affect ß-lactam pharmacokinetics in critically ill patients. Personalized ß-lactam dosing strategies were safe in critically ill patients and lead to high PK target attainment with less resources.

Continuous infusion, therapeutic drug monitoring and outpatient parenteral antimicrobial therapy with ceftazidime/avibactam: a retrospective cohort study

OBJECTIVES

Based on recent pharmacokinetic/pharmacodynamic (PK/PD) evidence, continuous-infusion (CI) β-lactam administration is increasingly recommended for serious infections. Since 2016, the combination ceftazidime/avibactam (CAZ/AVI) is administered as per the manufacturer's instructions as an intermittent infusion of 2.5 g every 8 h. Thus, CI has not yet been evaluated in clinical trials.

METHODS

We aimed to evaluate the use of CI of CAZ/AVI in a retrospective case series from December 2016 to October 2019. All isolates displayed in vitro susceptibility to CAZ/AVI according to EUCAST definitions. Patients were initially given CAZ/AVI as CI of 5 g every 12 h, and dosages were adjusted according to therapeutic drug monitoring of ceftazidime with a therapeutic goal of ≥4-5 × MIC in plasma and/or at the site of infection.

RESULTS

CAZ/AVI was administered by CI in 10 patients with infections mainly caused by multidrug-resistant Pseudomonas aeruginosa (54.5%) and Klebsiella pneumoniae (36.4%). Bacteraemia occurred in 30% of cases. Sepsis or septic shock was present in 20% of cases. CAZ/AVI was used as monotherapy in 60% of cases. Clinical cure and microbiological eradication were achieved in 80% and 90% of cases, respectively. The 30-day mortality after CAZ/AVI treatment onset was 10%. The therapeutic goals of ≥4-5 × MIC in plasma and/or at the site of infection were achieved in 100% and 87.5% of cases, respectively, without adverse events.

CONCLUSION

Despite a limited number of patients, CI of CAZ/AVI provided promising results after optimisation of PK/PD parameters both in plasma and at the site of infection.

Optimizing Pharmacokinetics-Pharmacodynamics of Antimicrobial Management in Patients with Sepsis: A Review

Critically ill patients with sepsis or septic shock are at an increased risk of death. Early and aggressive interventions are essential for improving clinical outcomes. There are a number of therapeutic and practical challenges in the management of antimicrobials in patients with sepsis. These include the timely selection and administration of appropriate antimicrobials, significant physiological alterations that can influence antimicrobial pharmacokinetics, and significant interpatient variability of antimicrobial concentrations using standard dosing approaches. Understanding the impact of these factors on the probability of attaining pharmacokinetic-pharmacodynamic target goals is essential to guide optimal therapy. Using rapid diagnostic technology could facilitate timely selection of antimicrobials, and therapeutic drug monitoring would provide a more individualized dosing approach. Using an interdisciplinary sepsis team would also be beneficial in coordinating efforts to overcome the challenges encountered during this critical period to ensure optimal care.

Quality of care indicators in the MAnageMent of BlOOdstream infections caused by Enterobacteriaceae (MAMBOO-E study): state of the art and research agenda

OBJECTIVES

The impact on outcome of five interventions was reviewed in order to investigate the state of the art for management of Enterobacteriaceae bloodstream infection (E-BSI).

METHODS

We searched for randomised controlled trials (RCTs) and observational studies published from January 2008 to March 2019 in PubMed, EMBASE and Cochrane Library. Populations consisted of patients with E-BSI. Interventions were as follows: (i) performance of imaging to assess BSI source and/or complications; (ii) follow-up blood cultures (FU-BCs); (iii) use of loading dose followed by extended/continuous infusion (E/CI) of β-lactams; (iv) duration of treatment (short- versus long-term); and (v) infectious diseases (ID) consultation. Patients without intervention were considered as controls. The main outcome was 30-day mortality. RoB 2.0 and ROBINS-I tools were used for bias assessment.

RESULTS

No study was eligible for interventions i, iii and v. For FU-BCs, one observational study including 901 patients with E-BSI was considered. Intervention consisted of repeating BCs within 2-7 days after index BCs. All-cause 30-day mortality was 14.2% (35/247) in the intervention group versus 14.7% (96/654) in the control group. For short treatment duration, two RCTs and six observational studies were included comprising 4473 patients with E-BSI. All-cause mortality was similar in the short and long treatment groups (OR = 1.10, 95% CI 0.83-1.44).

CONCLUSION

Of the assessed interventions, only short treatment duration in non-immunocompromised patients with E-BSI is supported by current data. Studies investigating the use of systematic imaging, FU-BCs, E/CI β-lactams and ID consultation in patients with E-BSI are needed.

A narrative review of predictors for β-lactam antibiotic exposure during empirical treatment in critically ill patients

INTRODUCTION

: Emerging studies suggest that antibiotic pharmacokinetics (PK) are difficult to predict in critically ill patients. The high intra- and inter-patient PK variability makes it challenging to accurately predict the appropriate dosage required for a given patient. Identifying patients at risk could help clinicians to consider more individualized dosing regimens and perform therapeutic drug monitoring. We provide an overview of relevant predictors associated with target (non-)attainment of β-lactam antibiotics in critically ill patients.

AREAS COVERED

: This narrative review summarizes patient and clinical characteristics that can help to predict the attainment of target serum concentrations and to provide guidance on antimicrobial dose optimization. Literature was searched using Embase and Medline database, focusing on β-lactam antibiotics in critically ill patients.

EXPERT OPINION

: Adequate concentration attainment can be anticipated in critically ill patients prior to initiating empiric β-lactam antibiotic therapy based on readily available demographic and clinical factors. Male gender, younger age, and augmented renal clearance were the most significant predictors for target non-attainment and should be considered in further investigations to develop dosing algorithms for optimal β-lactam therapy.

Clinical and pharmacokinetic/dynamic outcomes of prolonged infusions of beta-lactam antimicrobials: An overview of systematic reviews

OBJECTIVE

This overview of reviews aims to map and compare of objectives, methods, and findings of existing systematic reviews to develop a greater understanding of the information available about prolonged beta-lactam infusions in hospitalized patients with infection.

DESIGN

Overview of systematic reviews.

DATA SOURCES

Medline, Embase, PROSPERO and the Cochrane Library were systematically searched from January, 1990 to June, 2019 using a peer reviewed search strategy. Grey literature was also searched for relevant reviews.

ELIGIBILITY CRITERIA FOR SELECTING REVIEWS

Systematic reviews were sought that compared two or more infusion strategies for intravenous beta-lactam antimicrobials and report clinical cure or mortality. Populations of included reviews were restricted to hospitalized patients with infection, without restrictions on age, infection type, or disease.

DATA EXTRACTION AND ANALYSIS

Abstract screening, data extraction, quality and risk of bias assessment were conducted by two independent reviewers. Overlap between reviews was assessed using a modified corrected covered area. Overview findings are reported in accordance with Cochrane's recommendation for overview conduct. Clinical outcomes extracted included survival, clinical cure, treatment failure, microbiological cure, length of stay, adverse events, cost, and emergence of resistance.

RESULTS

The search strategy identified 3327 unique citations from which 21 eligible reviews were included. Reviews varied by population, intervention and outcomes studied. Between reviews, overlap of primary studies was generally high, methodologic quality generally low and risk of bias variable. Nine of 14 reviews that quantitatively evaluated mortality and clinical cure identified a benefit with prolonged infusions of beta lactams when compared with intermittent infusions. Evidence of mortality and clinical cure benefit was greater among critically ill patients when compared to less sick patients and lower in randomized controlled trials when compared with observational studies.

CONCLUSIONS

Findings from our review demonstrate a consistent and reproducible lack of harm with prolonged infusions of beta-lactam antibiotics with variability in effect size and significance of benefits. Despite 21 systematic reviews addressing prolonged infusions of beta-lactams, this overview supports the continued need for a definitive systematic review given variability in populations, interventions and outcomes in the current systematic reviews. Subsequent systematic reviews should have more rigorous and transparent methods, only include RCTs and evaluate the proposed benefits found in various subgroup-analyses-i.e. high risk of mortality.

TRIAL REGISTRATION

Prospero registry, CRD42019117118.

Rational dosage regimens for cephalothin and cefazolin using pharmacokinetics and pharmacodynamics analysis in healthy horses

BACKGROUND

First-generation cephalosporins have good activity against gram-positive bacteria and are extensively used in horses. There are few reports of pharmacokinetics and pharmacodynamics (PK/PD) analysis of cephalosporins in horses.

OBJECTIVE

To optimise the dosages of the two first-generation cephalosporins cephalothin (CET) and cefazolin (CEZ) in horses using PK/PD concepts.

STUDY DESIGN

Experimental study with single administration.

METHODS

Drug plasma concentrations following a single intravenous (i.v.) administration of 22 mg/kg bodyweight (bwt) CET in 12 horses and of 10 mg/kg bwt CEZ in six horses were measured using LC-MS/MS. Data were modelled using a nonlinear mixed effect modelling followed by Monte Carlo simulations. Minimum inhibitory concentrations (MICs) against Streptococcus zooepidemicus and Staphylococcus aureus isolated from horses were determined by the microbroth dilution method.

RESULTS

The percentages of CET and CEZ binding to serum proteins were 19.9% ± 8.4% and 15.2% ± 8.5% respectively. For both CET and CEZ, the MIC₉₀ against S. zooepidemicus was 0.12 mg/L and against S. aureus was 0.5 mg/L. For CET, to achieve a probability of target attainment (PTA) of 90% for a PK/PD target of a free serum plasma concentration exceeding the MIC₉₀ for 40% of the dosing interval, an empirical CET dosage regimen of 22 mg/kg bwt q8h and 22 mg/kg bwt q4h i.v. administration were required for S. zooepidemicus and S. aureus respectively. For CEZ, the corresponding dosage regimens were 10 mg/kg bwt q12h and 10 mg/kg bwt q8h.

MAIN LIMITATIONS

Small sample size only in healthy horses.

CONCLUSIONS

For CET, more frequent administration than that currently recommended (22 mg/kg bwt q6-12h) is required to empirically control S. aureus infection in horses. For CEZ, less frequent administration compared to the dosage regimen currently proposed (10-22 mg/kg bwt q6h) could control S. zooepidemicus and S. aureus infections in horses.

[Pharmacokinetic modifications and pharmacokinetic/pharmacodynamic optimization of beta-lactams in ICU]

Pharmacokinetic modifications in critically ill patients and those induced by ICU therapeutics raise a lot of issues about antibiotic dose adaptation. Beta-lactams are anti-infectious widely used in ICU. Frequent beta-lactam underdoses induce a risk of therapeutic failure potentially lethal and of emergence of bacterial resistance. Overdoses expose to a neurotoxic and nephrotoxic risk. Therefore, an understanding of pharmacokinetics modifications appears to be essential. A global pharmacokinetic/pharmacodynamic approach is required, including use of prolonged or continued beta-lactam infusions to optimise probability of pharmacokinetic/pharmacodynamic target attainment. Beta-lactam therapeutic drug monitoring should also be considered. Experts agree to target a free plasma betalactam concentration above four times the MIC of the causative bacteria for 100 % of the dosing interval. Bayesian methods could permit individualized doses adaptations.

A Population Pharmacokinetic Analysis of Continuous Infusion of Cloxacillin during Staphylococcus aureus Bone and Joint Infections

Intravenous administration of antibiotics is recommended during the early phase of methicillin-susceptible S. aureus (MSSA) bone and joint infection (BJI). We sought to compare the plasma concentrations of cloxacillin administered alternately by continuous and intermittent infusion (CI and ItI) in patients with MSSA BJI. In this prospective crossover trial, patients were randomly assigned to receive either 3 days of CI (two 75-mg/kg 12-h cloxacillin infusions per day) and then 3 days of ItI (four 37.5-mg/kg 1-h cloxacillin infusions per day) or vice versa. The drug concentration measurement was performed on day 3 of each type of administration at 1, 6, and 11 h and at 1, 2, 3, 4, and 6 h after the beginning of CI and ItI, respectively. We used the nonparametric algorithm NPAG to estimate population pharmacokinetic (PK) parameters. The final model was used to perform pharmacokinetic/pharmacodynamic (PK/PD) simulations and calculate the probabilities of target attainment (PTA) for several ItI and CI dosing regimens. We considered two PK/PD targets of time spent above the MIC for free cloxacillin concentrations (fT _>MIC): 50 and 100%. Eighty-four concentrations from 11 patients were analyzed. A two-compartment model adequately described the data. ItI with q6h regimens and short 1-h infusions of 2,000 or 3,000 mg were associated with low PTA, even for the low target (50% fT _>MIC) while 3-h infusions and continuous infusions (6 to 12 g/day) were associated with a PTA of >90% for an MIC up to 0.5 mg/liter. These results support the use of prolonged or continuous infusion of cloxacillin in patients with BJI.

Continuous infusion of cefepime and neurotoxicity: a retrospective cohort study

OBJECTIVES

Neurotoxicity related to cefepime is increasingly reported in the literature but specific data concerning continuous infusion (CI) of the drug are still lacking. Our primary objective was to evaluate the incidence of neurotoxicity related to CI of cefepime and the associated risk factors. Our secondary objectives were to analyse the plasma cefepime concentrations and to define the threshold above which neurotoxicity occurs.

METHODS

In this single-centre retrospective cohort study, all adult patients who underwent at least one cefepime therapeutic drug monitoring (TDM) and were treated with CI of 4 g/day between January 2017 and June 2019 were included. Neurotoxicity was evaluated according to a strict definition and was correlated with steady-state concentration at the time of toxicity presentation.

RESULTS

Ninety-eight patients with 201 cefepime TDM studies were included, with an incidence of neurotoxicity of 14.3% (14/98). Patients with neurotoxicity had more often underlying brain disease (35.7% (5/14) vs 11.9% (10/84), p = 0.030)) and higher steady-state concentrations (mean ± standard deviation 71.8 ± 32.9 mg/L vs 49.6 ± 30.6, p = 0.036) than the others. A receiver operating characteristic curve analysis yielded a cefepime steady-state concentration of 63.2 mg/L as the best cut-off point between patients with or without neurotoxicity. A mean steady-state concentration of 46.4 mg/L was achieved if the dosages of cefepime were adapted to renal function which was under our threshold concentration but above our highest pharmacokinetic/pharmacodynamic target of 32-40 mg/L.

CONCLUSIONS

Our results suggest that 4 g/day of cefepime adapted to renal function and infused over 24 h is a trade-off for the risk/benefit ratio, when used empirically.

Population Pharmacokinetics of Piperacillin following Continuous Infusion in Critically Ill Patients and Impact of Renal Function on Target Attainment

Pharmacokinetic changes are often seen in patients with severe infections. Administration by continuous infusion has been suggested to optimize antibiotic exposure and pharmacokinetic/pharmacodynamic (PK/PD) target attainment for β-lactams. In an observational study, unbound piperacillin concentrations (n = 196) were assessed in 78 critically ill patients following continuous infusion of piperacillin-tazobactam (ratio 8:1). The initial dose of 8, 12, or 16 g (piperacillin component) was determined by individual creatinine clearance (CRCL). Piperacillin concentrations were compared to the EUCAST clinical breakpoint MIC for Pseudomonas aeruginosa (16 mg/liter), and the following PK/PD targets were evaluated: 100% free time (fT) > 1× MIC and 100% fT > 4× MIC. A population pharmacokinetic model was developed using NONMEM 7.4.3 consisting of a one-compartment disposition model with linear elimination separated into nonrenal and renal (linearly increasing with patient CRCL) clearances. Target attainment was predicted and visualized for all individuals based on the utilized CRCL dosing algorithm. The target of 100% fT > 1× MIC was achieved for all patients based on the administered dose, but few patients achieved the target of 100% fT > 4× MIC. Probability of target attainment for a simulated cohort of patients showed that increasing the daily dose by 4-g increments (piperacillin component) did not result in substantially improved target attainment for the 100% fT > 4× MIC target. To conclude, in patients with high CRCL combined with high-MIC bacterial infections, even a continuous infusion (CI) regimen with a daily dose of 24 g may be insufficient to achieve therapeutic concentrations.

Clinical predictors and outcome impact of community-onset polymicrobial bloodstream infection

OBJECTIVES

Very few studies have characterised community-onset polymicrobial bloodstream infections (BSIs). This study determined the incidence, risk factors, and outcomes of polymicrobial BSI as compared with monomicrobial BSI in a cohort of patients with community-onset BSIs.

METHODS

This prospective cohort study enrolled consecutive patients with laboratory confirmed BSIs who were admitted to two tertiary emergency departments in Taiwan between 1 January 2015 and 31 December 2016. It assessed the independent impact of polymicrobial BSIs on survival by a propensity score weighting method. Subsequently, independent clinical predictors were identified with multivariate logistic regression model analysis with internal validation by 10-fold cross validation.

RESULTS

Among 1166 patients with community-onset BSI, 133 (10.9%) episodes of polymicrobial BSIs occurred. Anaerobe, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus spp., and Candida spp. were the most common isolated microorganisms in polymicrobial BSI. Polymicrobial BSIs were associated with an increased 90-day mortality rate (OR 2.20, 95% CI 1.98-2.60). A prediction model was built to predict polymicrobial BSI with moderate predictability (c statistic = 0.78). Significant predictors included biliary tract infection, nosocomial infection, nursing home residence, stroke, and afebrile presentation.

CONCLUSIONS

Polymicrobial BSI occurred in approximately 1 in 10 episodes of community-onset BSI and was independently associated with excess mortality. Clinical predictors identified in this study may help guide the prescription of empiric broad-spectrum antibiotics.

Therapeutic drug monitoring-guided continuous infusion of piperacillin/tazobactam significantly improves pharmacokinetic target attainment in critically ill patients: a retrospective analysis of four years of clinical experience

PURPOSE

Standard dosing and intermittent bolus application (IB) are important risk factors for pharmacokinetic (PK) target non-attainment during empirical treatment with β-lactams in critically ill patients, particularly in those with sepsis and septic shock. We assessed the effect of therapeutic drug monitoring-guided (TDM), continuous infusion (CI) and individual dosing of piperacillin/tazobactam (PIP) on PK-target attainment in critically ill patients.

METHODS

This is a retrospective, single-center analysis of a database including 484 patients [933 serum concentrations (SC)] with severe infections, sepsis and septic shock who received TDM-guided CI of PIP in the intensive care unit (ICU) of an academic teaching hospital. The PK-target was defined as a PIP SC between 33 and 64 mg/L [fT > 2-4 times the epidemiological cutoff value (ECOFF) of Pseudomonas aeruginosa (PSA)].

RESULTS

PK-target attainment with standard dosing (initial dose) was observed in 166 patients (34.3%), whereas only 49 patients (10.1%) demonstrated target non-attainment. The minimum PK-target of ≥ 33 mg/L was overall realized in 89.9% (n = 435/484) of patients after the first PIP dose including 146 patients (30.2%) with potentially harmful SCs ≥ 100 mg/L. Subsequent TDM-guided dose adjustments significantly enhanced PK-target attainment to 280 patients (62.4%) and significantly reduced the fraction of potentially overdosed (≥ 100 mg/L) patients to 4.5% (n = 20/449). Renal replacement therapy (RRT) resulted in a relevant reduction of PIP clearance (CL_PIP): no RRT CL_PIP 6.8/6.3 L/h (median/IQR) [SCs n = 752, patients n = 405], continuous veno-venous hemodialysis (CVVHD) CL_PIP 4.3/2.6 L/h [SCs n = 160, n = 71 patients], intermittent hemodialysis (iHD) CL_PIP 2.6/2.3 L/h [SCs n = 21, n = 8 patients]). A body mass index (BMI) of > 40 kg/m² significantly increased CL_PIP 9.6/7.7 L/h [SC n = 43, n = 18 patients] in these patients. Age was significantly associated with supratherapeutic PIP concentrations (p < 0.0005), whereas high CrCL led to non-target attainment (p < 0.0005). Patients with target attainment (33-64 mg/L) within the first 24 h exhibited the lowest hospital mortality rates (13.9% [n = 23/166], p < 0.005). Those with target non-attainment demonstrated higher mortality rates (≤ 32 mg/L; 20.8% [n = 10/49] ≥ 64 mg/L; 29.4% [n = 79/269]).

CONCLUSION

TDM-guided CI of PIP is safe in critically ill patients and improves PK-target attainment. Exposure to defined PK-targets impacts patient mortality while lower and higher than intended SCs may influence the outcome of critically ill patients. Renal function and renal replacement therapy are main determinants of PK-target attainment. These results are only valid for CI of PIP and not for prolonged or intermittent bolus administration of PIP.

Optimization of the treatment with beta-lactam antibiotics in critically ill patients-guidelines from the French Society of Pharmacology and Therapeutics (Société Française de Pharmacologie et Thérapeutique-SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation-SFAR)

BACKGROUND

Beta-lactam antibiotics (βLA) are the most commonly used antibiotics in the intensive care unit (ICU). ICU patients present many pathophysiological features that cause pharmacokinetic (PK) and pharmacodynamic (PD) specificities, leading to the risk of underdosage. The French Society of Pharmacology and Therapeutics (SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (SFAR) have joined forces to provide guidelines on the optimization of beta-lactam treatment in ICU patients.

METHODS

A consensus committee of 18 experts from the two societies had the mission of producing these guidelines. The entire process was conducted independently of any industry funding. A list of questions formulated according to the PICO model (Population, Intervention, Comparison, and Outcomes) was drawn-up by the experts. Then, two bibliographic experts analysed the literature published since January 2000 using predefined keywords according to PRISMA recommendations. The quality of the data identified from the literature was assessed using the GRADE® methodology. Due to the lack of powerful studies having used mortality as main judgement criteria, it was decided, before drafting the recommendations, to formulate only "optional" recommendations.

RESULTS

After two rounds of rating and one amendment, a strong agreement was reached by the SFPT-SFAR guideline panel for 21 optional recommendations and a recapitulative algorithm for care covering four areas: (i) pharmacokinetic variability, (ii) PK-PD relationship, (iii) administration modalities, and (iv) therapeutic drug monitoring (TDM). The most important recommendations regarding βLA administration in ICU patients concerned (i) the consideration of the many sources of PK variability in this population; (ii) the definition of free plasma concentration between four and eight times the Minimal Inhibitory Concentration (MIC) of the causative bacteria for 100% of the dosing interval as PK-PD target to maximize bacteriological and clinical responses; (iii) the use of continuous or prolonged administration of βLA in the most severe patients, in case of high MIC bacteria and in case of lower respiratory tract infection to improve clinical cure; and (iv) the use of TDM to improve PK-PD target achievement.

CONCLUSIONS

The experts strongly suggest the use of personalized dosing, continuous or prolonged infusion and therapeutic drug monitoring when administering βLA in critically ill patients.

Evaluation of Meropenem Extended Versus Intermittent Infusion Dosing Protocol in Critically Ill Patients

Extended infusion (EI) administration of β-lactams can improve target attainment in critically ill patients with altered pharmacokinetics/pharmacodynamics. To optimize meropenem dosing in patients with severe sepsis/septic shock, our Antimicrobial Stewardship Program implemented a EI meropenem (EIM) protocol in an 18-bed Medical Intensive Care Unit in March 2014. In this retrospective study, we compared intensive care unit (ICU) mortality and clinical response in patients who received meropenem for ≥72 hours administered per EIM protocol of 1 g over 3 hours every 8 hours versus intermittent infusion (IIM) protocol of 500 mg over 30 minutes every 6 hours. Age, weight, comorbidities, severity of illness, and vasopressor use were comparable between groups (EIM protocol n = 52, IIM protocol n = 96). The IIM protocol group had higher rates of renal dose adjustment at meropenem initiation. Among 56 identified gram-negative (GN) pathogens, 94% had meropenem minimal inhibitory concentration ≤0.25 mg/L. The ICU mortality was lower (19 vs 37%; P = .032) and clinical response was higher (83% vs 46%; P < .01) in the EIM protocol versus IIM protocol group. Total vasopressor days were shorter (2 vs 3 days; P = .038), and white blood cell normalization rate was higher (87% vs 51%; P < .01) in the EIM protocol versus IIM protocol group. There was no difference in days of mechanical ventilation, duration of therapy, and ICU stay. The IIM protocol was also identified as an independent risk factor associated with ICU mortality (hazard ratio: 3.653, 95% confidence interval: 1.689-7.981; P = .001) after adjusting for Sequential Organ Failure Assessment score. In this cohort of patients with severe sepsis/septic shock and highly susceptible GN pathogens, there was improved mortality and clinical response in the EIM protocol group.