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)

Determinants of beta-lactam PK/PD target attainment in critically ill patients: A single center retrospective study

PURPOSE

We aimed to identify factors associated with achieving target BL plasma concentrations and describe real world data for therapeutic drug monitoring (TDM).

METHODS

A retrospective single center study was conducted. We collected data from patients admitted to ICU with at least one BL TDM. We assessed the proportion of patients attaining the recommended plasma concentrations (i.e 100%fT > 4 to 8 MIC). Univariate and multivariate analyses was performed to identify the determinants of BL target attainment.

RESULTS

156 patients were included. At the first dosing, 34% achieved target BL plasma concentrations, 50% were overdosed, and 16% were underdosed. Median time for 1st TDM were 4 (SD = 2.9) days. Multivariate analysis revealed that CKD-EPI estimated glomerular filtration rate (OR = 1.02; CI [1.01; 1.03]; p < 0.0001) and total body weight (OR = 1.03; CI [1.01; 1.04]; p = 0.0048) were the main determinant of BL target attainment. Conversely, Continuous Renal Replacement Therapy (OR = 0.28; CI [0.09; 0.89]; p = 0.0318) and meropenem use (OR = 0.31; CI [0.14; 0.69]; p = 0.0041) were identified as risk factors for overdosing. No factor was associated with underdosing.

CONCLUSION

Achieving target BL plasma concentrations remains challenging in ICUs. Identifying predictive factors of BL target attainment would favor implementing rapid dosing optimization strategies in both under and overdosing high risk patients.

Prolonged Beta-lactam Infusions in Children: A Systematic Review and Meta-analysis

OBJECTIVE

To assess whether beta-lactam extended or continuous beta-lactam infusions (EI/CI) improve clinical outcomes in children with proven or suspected bacterial infections.

STUDY DESIGN

We included observational and interventional studies that compared beta-lactam EI or CI with standard infusions in children less than 18 years old, and reported on mortality, hospital or intensive care unit LOS, microbiological cure and/or clinical cure. Data sources included PubMed, Medline, EBM Reviews, EMBASE, and CINAHL and were searched from January 1, 1980, to November 3, 2023. Thirteen studies (2,945 patients) were included: 5 randomized control trials (RCTs), and 8 observational studies. Indications for antimicrobial therapies and clinical severity varied, ranging from cystic fibrosis exacerbation to critically ill children with bacteriemia.

RESULTS

EI and CI were not associated with a reduction in mortality in RCTs (n = 1,464; RR 0.93, 95% CI 0.71, 1.21), but were in observational studies (n = 833; RR 0.43, 95% CI 0.19, 0.96). We found no difference in hospital length of stay. Results for clinical and microbiological cures were heterogeneous and reported as narrative review. The included studies were highly heterogeneous, limiting the strength of our findings. The lack of shared definitions for clinical and microbiological cure outcomes precluded analysis.

CONCLUSIONS

EI and CI were not consistently associated with reduced mortality or LOS in children. Results were conflicting regarding clinical and microbiological cures. More well-designed studies targeting high-risk populations are necessary to determine the efficacy of these alternative dosing strategies.

Dose optimization of β-lactam antibiotics in children: from population pharmacokinetics to individualized therapy

INTRODUCTION

β-Lactams are the most widely used antibiotics in children. Their optimal dosing is essential to maximize their efficacy, while minimizing the risk for toxicity and the further emergence of antimicrobial resistance. However, most β-lactams were developed and licensed long before regulatory changes mandated pharmacokinetic studies in children. As a result, pediatric dosing practices are poorly harmonized and off-label use remains common today.

AREAS COVERED

β-Lactam pharmacokinetics and dose optimization strategies in pediatrics, including fixed dose regimens, therapeutic drug monitoring, and model-informed precision dosing are reviewed.

EXPERT OPINION/COMMENTARY

Standard pediatric doses can result in subtherapeutic exposure and non-target attainment for specific patient subpopulations (neonates, critically ill children, e.g.). Such patients could benefit greatly from more individualized approaches to dose optimization, beyond a relatively simple dose adaptation based on weight, age, or renal function. In this context, Therapeutic Drug Monitoring (TDM) and Model-Informed Precision Dosing (MIPD) emerge as particularly promising avenues. Obstacles to their implementation include the lack of strong evidence of clinical benefit due to the paucity of randomized clinical trials, of standardized assays for monitoring concentrations, or of adequate markers for renal function. The development of precision medicine tools is urgently needed to individualize therapy in vulnerable pediatric subpopulations.

The New Delhi metallo-β-lactamase-1 biosensor rapidly and accurately detected antibiotic plasma concentrations in cefuroxime-treated patients

OBJECTIVES

Therapeutic drug monitoring (TDM) of β-lactam antibiotics in critically ill patients may benefit dose optimisation, thus improving therapeutic outcomes. However, rapidly and accurately detecting these antibiotics in blood remains a challenge. This research group recently developed a thermometric biosensor called the New Delhi metallo-β-lactamase-1 (NDM-1) biosensor, which detects multiple classes of β-lactam antibiotics in spiked plasma samples.

METHODS

This study assessed the NDM-1 biosensor's effectiveness in detecting plasma concentrations of β-lactam antibiotics in treated patients. Seven patients receiving cefuroxime were studied. Plasma samples collected pre- and post-antibiotic treatment were analysed using the NDM-1 biosensor and compared with liquid chromatography coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

RESULTS

The biosensor detected plasma samples without dilution, and a brief pre-treatment using a polyvinylidene fluoride filter significantly lowered matrix effects, reducing the running time to 5-8 minutes per sample. The assay's linear range for cefuroxime (6.25-200 mg/L) covered target concentrations during the trough phase of pharmacokinetics in critically ill patients. The pharmacokinetic properties of cefuroxime in treated patients determined by the NDM-1 biosensor and the UPLC-MS/MS were comparable, and the cefuroxime plasma concentrations measured by the two methods showed statistically good consistency.

CONCLUSION

These data demonstrate that the NDM-1 biosensor assay is a fast, sensitive, and accurate method for detecting cefuroxime plasma concentrations in treated patients and highlights the NDM-1 biosensor as a promising tool for on-site TDM of β-lactam antibiotics in critically ill patients.

The effects of single and multiple resistance mechanisms on bacterial response to meropenem

OBJECTIVES

Meropenem is commonly used against Pseudomonas aeruginosa. Traditionally, the time unbound antibiotic concentration exceeds the MIC (fT>MIC) is used to select carbapenem regimens. We aimed to characterize the effects of different baseline resistance mechanisms on bacterial killing and resistance emergence; evaluate whether fT>MIC can predict these effects; and, develop a novel Quantitative and Systems Pharmacology (QSP) model to describe the effects of baseline resistance mechanisms on the time-course of bacterial response.

METHODS

Seven isogenic P. aeruginosa strains with a range of resistance mechanisms and MICs were used in 10-day hollow-fiber infection model studies. Meropenem pharmacokinetic profiles were simulated for various regimens (t1/2,meropenem = 1.5 h). All viable counts on drug-free, 3 × MIC, and 5 × MIC meropenem-containing agar across all strains, five regimens, and control (n = 90 profiles) were simultaneously subjected to QSP modeling. Whole genome sequencing was completed for total population samples and emergent resistant colonies at 239 h.

RESULTS

Regimens achieving ≥98%fT>1×MIC suppressed resistance emergence of the mexR knockout strain. Even 100%fT>5 × MIC failed to achieve this against the strain with OprD loss and the ampD and mexR double-knockout strain. Baseline resistance mechanisms affected bacterial outcomes, even for strains with the same MIC. Genomic analysis revealed that pre-existing resistant subpopulations drove resistance emergence. During meropenem exposure, mutations in mexR were selected in strains with baseline oprD mutations, and vice versa, confirming these as major mechanisms of resistance emergence. Secondary mutations occurred in lysS or argS, coding for lysyl and arginyl tRNA synthetases, respectively.

DISCUSSION

The QSP model well-characterized all bacterial outcomes of the seven strains simultaneously, which fT>MIC could not.

Use of the DMAIC Lean Six Sigma quality improvement framework to improve beta-lactam antibiotic adequacy in the critically ill

Beta-lactam antibiotics are widely used in the intensive care unit due to their favorable effectiveness and safety profiles. Beta-lactams given to patients with sepsis must be delivered as soon as possible after infection recognition (early), treat the suspected organism (appropriate), and be administered at a dose that eradicates the infection (adequate). Early and appropriate antibiotic delivery occurs in >90% of patients, but less than half of patients with sepsis achieve adequate antibiotic exposure. This project aimed to address this quality gap and improve beta-lactam adequacy using the Define, Measure, Analyze, Improve, and Control Lean Six Sigma quality improvement framework. A multidisciplinary steering committee was formed, which completed a stakeholder analysis to define the gap in practice. An Ishikawa cause and effect (Fishbone) diagram was used to identify the root causes and an impact/effort grid facilitated prioritization of interventions. An intervention that included bundled education with the use of therapeutic drug monitoring (TDM; i.e. drug-level testing) was projected to have the highest impact relative to the amount of effort and selected to address beta-lactam inadequacy in the critically ill. The education and TDM intervention were deployed through a Plan, Do, Study, Act cycle. In the 3 months after "go-live," 54 episodes of beta-lactam TDM occurred in 41 unique intensive care unit patients. The primary quality metric of beta-lactam adequacy was achieved in 94% of individuals after the intervention. Ninety-four percent of clinicians gauged the education provided as sufficient. The primary counterbalance of antimicrobial days of therapy, a core antimicrobial stewardship metric, was unchanged over time (favorable result; P = .73). Application of the Define, Measure, Analyze, Improve, and Control Lean Six Sigma quality improvement framework effectively improved beta-lactam adequacy in critically ill patients. The approach taken in this quality improvement project is widely generalizable to other drugs, drug classes, or settings to increase the adequacy of drug exposure.

Does Two-Step Infusion Improve the Pharmacokinetics/Pharmacodynamics Target Attainment of Meropenem in Critically Ill Patients?

The optimal method for administering meropenem remains controversial. This study was conducted to explore the optimal two-step infusion strategy (TIT), and to investigate whether TIT is superior to intermittent infusion therapy (IIT) and prolonged infusion therapy (PIT). A physiologically based pharmacokinetics model for critically ill patients was established and evaluated. The validated model was utilized to evaluate the pharmacokinetics/pharmacodynamics (PK/PD) target attainment of meropenem. The PK/PD target attainment of different TITs varied greatly, and the total infusion duration and the first-step dose greatly affected these values. The optimal TIT was 0.25 g (30 min) + 0.75 g (150 min) at MICs of ≤2 mg/L, and 0.25 g (45 min) + 0.75 g (255 min) at MICs of 4-8 mg/L. The PK/PD target attainment of optimal TIT, PIT, and IIT were 100 % at MICs of ≤1 mg/L. When MIC increased to 2-8 mg/L, the PK/PD target attainment of optimal TIT was similar to that of PIT and higher than IIT. In conclusion, TIT did not significantly improve the PK/PD target attainment of meropenem compared with PIT. IIT is adequate at MICs of ≤1 mg/L, and PIT may be the optimal meropenem infusion method in critically ill patients with MICs of 2-8 mg/L.

Understanding antimicrobial pharmacokinetics in critically ill patients to optimize antimicrobial therapy: A narrative review

Effective treatment of sepsis not only demands prompt administration of appropriate antimicrobials but also requires precise dosing to enhance the likelihood of patient survival. Adequate dosing refers to the administration of doses that yield therapeutic drug concentrations at the infection site. This ensures a favorable clinical and microbiological response while avoiding antibiotic-related toxicity. Therapeutic drug monitoring (TDM) is the recommended approach for attaining these goals. However, TDM is not universally available in all intensive care units (ICUs) and for all antimicrobial agents. In the absence of TDM, healthcare practitioners need to rely on several factors to make informed dosing decisions. These include the patient's clinical condition, causative pathogen, impact of organ dysfunction (requiring extracorporeal therapies), and physicochemical properties of the antimicrobials. In this context, the pharmacokinetics of antimicrobials vary considerably between different critically ill patients and within the same patient over the course of ICU stay. This variability underscores the need for individualized dosing. This review aimed to describe the main pathophysiological changes observed in critically ill patients and their impact on antimicrobial drug dosing decisions. It also aimed to provide essential practical recommendations that may aid clinicians in optimizing antimicrobial therapy among critically ill patients.

Optimal use of β-lactams in neonates: machine learning-based clinical decision support system

BACKGROUND

Accurate prediction of the optimal dose for β-lactam antibiotics in neonatal sepsis is challenging. We aimed to evaluate whether a reliable clinical decision support system (CDSS) based on machine learning (ML) can assist clinicians in making optimal dose selections.

METHODS

Five β-lactam antibiotics (amoxicillin, ceftazidime, cefotaxime, meropenem and latamoxef), commonly used to treat neonatal sepsis, were selected. The CDSS was constructed by incorporating the drug, patient, dosage, pharmacodynamic, and microbiological factors. The CatBoost ML algorithm was used to build the CDSS. Real-world studies were used to evaluate the CDSS performance. Virtual trials were used to compare the CDSS-optimized doses with guideline-recommended doses.

FINDINGS

For a specific drug, by entering the patient characteristics and pharmacodynamic (PD) target (50%/70%/100% fraction of time that the free drug concentration is above the minimal inhibitory concentration [fT > MIC]), the CDSS can determine whether the planned dosing regimen will achieve the PD target and suggest an optimal dose. The prediction accuracy of all five drugs was >80.0% in the real-world validation. Compared with the PopPK model, the overall accuracy, precision, recall, and F1-Score improved by 10.7%, 22.1%, 64.2%, and 43.1%, respectively. Using the CDSS-optimized doses, the average probability of target concentration attainment increased by 58.2% compared to the guideline-recommended doses.

INTERPRETATION

An ML-based CDSS was successfully constructed to assist clinicians in selecting optimal β-lactam antibiotic doses.

FUNDING

This work was supported by the National Natural Science Foundation of China; Distinguished Young and Middle-aged Scholar of Shandong University; National Key Research and Development Program of China.

Personalized Amoxicillin Therapy in a Critically Ill Patient Undergoing Renal Replacement Therapy: A Grand Round

BACKGROUND

The case study discusses a complex scenario involving the use of amoxicillin in a critically ill patient undergoing intermittent renal replacement therapy.Severe infections are complicated by septic shock and organ failure, requiring urgent and effective antibiotic treatment.

METHODS

The patient's comorbidities, including obesity and acute kidney injury, required careful consideration of the amoxicillin dosing strategies.

RESULTS

Therapeutic drug monitoring is critical for dose adjustment during treatment.

CONCLUSIONS

This case highlights the importance of a collaborative approach between clinicians and therapeutic drug monitoring consultants to optimize antibiotic therapy for critically ill patients with renal impairment.

Should we, and how to, optimize cefiderocol administration during severe nosocomial pneumonia due to carbapenem-resistant Acinetobacter baumanii? A viewpoint

OBJECTIVES

Acinetobacter baumannii is classified by the centre for Disease Control and Prevention (CDC) as an "urgent threat" due to its ability to acquire and develop resistance to multiple classes of antibiotics. As a result, it is one of the most concerning pathogens in healthcare settings, with increasing incidence of infections due to carbapenem-resistant Acinetobacter baumannii (CRAB) associated with high morbidity and mortality rates. Therefore, there are ongoing efforts to find novel treatment options, one of which is cefiderocol. We aim to review available evidence on cefiderocol use for severe nosocomial pneumonia due to carbapenem-resistant Acinetobacter baumannii.

METHODS

A comprehensive review was conducted from 2017 to 2023, covering articles from databases such as Pubmed, Scopus, and Embase, along with conference proceedings from ECCMID 2023. The primary focus was on severe nosocomial pneumonia due A. baumannii and cefiderocol.

DISCUSSION

Cefiderocol, targeting periplasmic space Penicillin-Binding Proteins (PBPs) via siderophore transport pathways, exhibits promise against multi-drug resistant Gram-negative bacilli. Its effectiveness in treating CRAB pneumonia remains debated. The CREDIBLE trial reported higher mortality with cefiderocol compared to the best available treatment, while other cohort studies showed contrasting outcomes. Patient variations and pharmacokinetic factors may underlie these discrepancies. The recommended cefiderocol dosage regimen may fall short of desired pharmacokinetic targets, especially in critically ill patients and lung infections. Pulmonary factors hindering cefiderocol's entry into bacteria through iron transporters are overlooked in clinical breakpoints. Optimized dosing or combination regimens may enhance infection site exposure and outcomes.

CONCLUSIONS

Further research is needed to determine the optimal cefiderocol dosage and administration (mono vs. dual therapy, continuous vs. intermittent infusion), in severe Acinetobacter baumannii nosocomial pneumonia.

Implementation Strategies Addressing Stakeholder-Perceived Barriers and Enablers to the Establishment of a Beta-Lactam Antibiotic Therapeutic Drug Monitoring Program: A Qualitative Analysis

BACKGROUND

Therapeutic drug monitoring (TDM) of beta-lactam antibiotics (beta-lactams) is increasingly recommended for optimizing antibiotic exposure in intensive care patients with sepsis. However, limited data are available on the implementation of beta-lactam TDM in complex health care settings. Theory-based approaches were used to systematically explore barriers and enablers perceived by key stakeholders in the implementation of beta-lactam TDM in the intensive care unit.

METHODS

In this qualitative descriptive study, the authors interviewed key stakeholders (n = 40): infectious disease physicians, intensive care unit physicians, pharmacists, clinical leaders, scientists, and nurses. The data were thematically analyzed and coded using the theoretical domains framework, and the codes and themes were mapped to the relevant domains of the capability, opportunity, and motivation behavior-change wheel model.

RESULTS

Barriers included a lack of knowledge, experience, evidence, and confidence, which led to concerns about capability, lack of resources, and harm in straying from standard practice. Access to education and guidelines, on-site assays with short turnaround times, communication among teams, and workflow integration were identified as enablers. A focus on patient care, trust in colleagues, and endorsement by hospital leaders were strong motivators. Pharmacist and nursing stakeholder groups emerged as key targets in the implementation of strategies.

CONCLUSIONS

Using theory-based approaches, the authors identified the key barriers and enablers to establishing beta-lactam TDM. These data were used to identify strategies, policies, and key target groups for the implementation of interventions.

In vitro activity, pharmacodynamic profile and dose optimization of biapenem against NDM and OXA-48-like carbapenemase-producing Klebsiella pneumoniae: A multicentre study in Thailand

BACKGROUND

Biapenem (BIPM) exhibited a less efficient substrate for various metallo-β-lactamase (MBL) than other carbapenems.

OBJECTIVE

We aimed to evaluate in vitro susceptibility data of BIPM and optimal dose based on Monte Carlo simulation to extend treatment options.

METHODS

We collected 192 carbapenem-resistant Klebsiella pneumoniae (CRKP) clinical isolates from unique patients among multicentres in Thailand, from June 2019 to March 2023. BIPM disk diffusion and broth-microdilution testing were performed to obtain minimum inhibitory concentration (MIC). Each BIPM regimen was simulated using the Monte Carlo technique to calculate the probability of target attainment (PTA) and the cumulative fraction of response (CFR).

RESULTS

The most common genotypes among 192 CRKP isolates were blaOXA-48 (62.3%), blaOXA-48+blaNDM (22.6%) and blaNDM (15.1%). BIPM showed 22.4 and 28.6% susceptible rate when interpreted at clinical breakpoints of 1 and 2 mg/L. The MIC50 and MIC90 of BIPM against CRKP were 8 and 32 mg/L. The BIPM dosing regimens of 300 mg q 6 h infused 6 h and 600 mg q 8 h infused 8 h met the PTA target of %fTime >MIC at 50%, 75% and 100% against isolates MICs of ≤2 mg/L. Based on CFR ≥90%, no BIPM regimens were effective against all the studied CRKP isolates.

CONCLUSION

BIPM exhibited a partially susceptible rate among the CRKP isolates in Thailand. The current suggested dose of BIPM with prolonged infusion appears appropriate regimen against CRKP MICs of ≤2 mg/L. However, the empirical use of BIPM for severe CRE infection is not recommended unless the susceptibility has been confirmed.

Estimated glomerular filtration rate as a tool for early identification of patients with insufficient exposure to beta-lactam antibiotics in intensive care units

BACKGROUND

Only about 50% of intensive care unit (ICU) patients reach a free trough concentration above MIC (100% fT > MIC) of beta-lactam antibiotics. Although dose adjustments based on therapeutic drug monitoring (TDM) could be beneficial, TDM is not widely available. We investigated serum creatinine-based estimated GFR (eGFR) as a rapid screening tool to identify ICU patients at risk of insufficient exposure.

METHOD

Ninety-three adult patients admitted to four ICUs in southeast Sweden treated with piperacillin/tazobactam, meropenem, or cefotaxime were included. Beta-lactam trough concentrations were measured. The concentration target was set to 100% fT > MICECOFF (2, 4, and 16 mg/L based on calculated free levels for meropenem, cefotaxime, and piperacillin, respectively). eGFR was primarily determined via Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and compared to three other eGFR equations. Data was analysed using logistic regression and receiver operative characteristic (ROC) curves.

RESULTS

With intermittent standard dosing, insufficient exposure was common in patients with a relative eGFR ≥48mL/min/1.73m2 [85%, (45/53)], particularly when treated with cefotaxime [96%, (24/25)]. This eGFR cut-off had a sensitivity of 92% and specificity of 82% (AUC 0.871, p < 0.001) in identifying insufficient exposure. In contrast, patients with eGFR <48mL/min/1.73m2 had high target attainment [90%, (36/40)] with a wide variability in drug exposure. There was no difference between the four eGFR equations (AUC 0.866-0.872, cut-offs 44-51 ml/min/1.73m2).

CONCLUSION

Serum creatinine-based eGFR is a simple and widely available surrogate marker with potential for early identification of ICU patients at risk of insufficient exposure to piperacillin, meropenem, and cefotaxime.

Ceftazidime-related neurotoxicity in a patient with renal impairment: a case report and literature review

PURPOSE

We present the case of a 67-year-old woman with severely reduced renal clearance suffering from ceftazidime-induced encephalopathy. Subsequently, we search the literature to review and describe the neurotoxicity of ceftazidime.

METHODS

A search string was developed to search PubMed for relevant cases from which relevant information was extracted. Using the collected data a ROC analysis was performed in R to determine a neurotoxicity threshold.

RESULTS

Our patient suffered from progressive loss of consciousness and myoclonic seizures, with improvements noted a few days after discontinuation of treatment. The dose was not appropriately reduced to take into account her reduced renal function. The highest ceftazidime concentration recorded was 234.9 mg/mL. Using the Naranjo score we found a probable relationship between our patient's encephalopathy and ceftazidime administration. In the literature we found a total of 32 similar cases, most of which also had some form of renal impairment. Using our collected data and ceftazidime concentrations provided in the literature, a ROC analysis provided a neurotoxicity threshold of 78 mg/L for ceftazidime neurotoxicity.

CONCLUSION

Ceftazidime-related neurotoxicity is a known issue, especially in patients with severe renal impairment. Yet no concrete toxicity threshold has been reported so far. We propose the first toxicity threshold for ceftazidime of 78 mg/L. Future prospective studies are needed to validate and optimize the neurotoxicity threshold as upper limit for ceftazidime therapeutic drug monitoring.

A high performance liquid chromatography-tandem mass spectrometry assay for therapeutic drug monitoring of 10 drug compounds commonly used for antimicrobial therapy in plasma and serum of critically ill patients: Method optimization, validation, cross-validation and clinical application

BACKGROUND AND AIMS

Intensive care antibiotic treatment faces challenges due to substantial pharmacokinetic differences in critically ill patients. Individualized antibiotic dosing guided by therapeutic drug monitoring (TDM) is considered to minimize the risk of treatment failure and toxicity. This study aimed to develop a valid method for simultaneous LC-MS/MS quantification of 10 drugs frequently used in intensive care antibiotic therapy for which TDM-guided dosing is recommended: piperacillin, meropenem, flucloxacillin, cefuroxime, vancomycin, colistin A and B, linezolid, ciprofloxacin and tazobactam.

METHODS AND RESULTS

Thorough optimization of sample preparation and chromatography resulted in a fast and simple method based on protein precipitation of 50 µL plasma or serum and gradient elution using an Acquity UPLC HSS-T3 column. Electrospray ionization-triple quadrupole mass spectrometry in dynamic multiple reaction monitoring was used for quantification, covering the therapeutic range of each drug compound. Validation following EMA and FDA recommendations, including inter-platform validation and inter-laboratory comparison, demonstrated high accuracy, precision and robustness of the new method. The assay was successfully used to monitor plasma antibiotic levels of critically ill patients (n = 35).

CONCLUSION

The established multiplex method covers major drug classes with documented dosing challenges, provides a reliable basis for the implementation of high-throughput TDM, and its application confirmed the clinical impact of TDM in a real-world setting.

Changes of PK/PD of Meropenem in patients with abdominal septic shock and exploration of clinical rational administration plan: a prospective exploratory study

This study aimed to explore the changes of pharmacokinetic parameters after meropenem in patients with abdominal septic shock after gastrointestinal perforation, and to simulate the probability of different dosing regimens achieving different pharmacodynamic goals. The study included 12 patients, and utilized high performance liquid chromatography-tandem mass spectrometry to monitor the plasma concentration of meropenem. The probability of target attainment (PTA) for different minimum inhibitory concentration (MIC) values and %fT > 4MIC was compared among simulated dosing regimens. The results showed that in 96 blood samples from 12 patients, the clearance (CL) of meropenem in the normal and abnormal creatinine clearance subgroups were 7.7 ± 1.8 and 4.4 ± 1.1 L/h, respectively, and the apparent volume of distribution (Vd) was 22.6 ± 5.1 and 17.2 ± 5.8 L, respectively. 2. Regardless of the subgroup, 0.5 g/q6h infusion over 6 h regimen achieved a PTA > 90% when MIC ≤ 0.5 mg/L. 1.0 g/q6h infusion regimen compared with other regimen, in most cases, the probability of making PTA > 90% is higher. For patients at low MIC, 0.5 g/q6h infusion over 6 h may be preferable. For patients at high MIC, a dose regimen of 1.0 g/q6 h infusion over 6 h may be preferable. Further research is needed to confirm this exploratory result.

Updated antimicrobial dosing recommendations for obese patients

The prevalence of obesity has increased considerably in the last few decades. Pathophysiological changes in obese patients lead to pharmacokinetic (PK) and pharmacodynamic (PD) alterations that can condition the correct exposure to antimicrobials if standard dosages are used. Inadequate dosing in obese patients can lead to toxicity or therapeutic failure. In recent years, additional antimicrobial PK/PD data, extended infusion strategies, and studies in critically ill patients have made it possible to obtain data to provide a better dosage in obese patients. Despite this, it is usually difficult to find information on drug dosing in this population, which is sometimes contradictory. This is a comprehensive review of the dosing of different types of antimicrobials (antibiotics, antifungals, antivirals, and antituberculosis drugs) in obese patients, where the literature on PK and possible dosing strategies in obese adults was critically assessed.

Impact of attaining aggressive vs. conservative PK/PD target on the clinical efficacy of beta-lactams for the treatment of Gram-negative infections in the critically ill patients: a systematic review and meta-analysis

BACKGROUND

To perform a systematic review with meta-analysis with the dual intent of assessing the impact of attaining aggressive vs. conservative beta-lactams PK/PD target on the clinical efficacy for treating Gram-negative infections in critical patients, and of identifying predictive factors of failure in attaining aggressive PK/PD targets.

METHODS

Two authors independently searched PubMed-MEDLINE and Scopus database from inception to 23rd December 2023, to retrieve studies comparing the impact of attaining aggressive vs. conservative PK/PD targets on clinical efficacy of beta-lactams. Independent predictive factors of failure in attaining aggressive PK/PD targets were also assessed. Aggressive PK/PD target was considered a100%fT>4xMIC, and clinical cure rate was selected as primary outcome. Meta-analysis was performed by pooling odds ratios (ORs) extrapolated from studies providing adjustment for confounders using a random-effects model with inverse variance method.

RESULTS

A total of 20,364 articles were screened, and 21 observational studies were included in the meta-analysis (N = 4833; 2193 aggressive vs. 2640 conservative PK/PD target). Attaining aggressive PK/PD target was significantly associated with higher clinical cure rate (OR 1.69; 95% CI 1.15-2.49) and lower risk of beta-lactam resistance development (OR 0.06; 95% CI 0.01-0.29). Male gender, body mass index > 30 kg/m2, augmented renal clearance and MIC above the clinical breakpoint emerged as significant independent predictors of failure in attaining aggressive PK/PD targets, whereas prolonged/continuous infusion administration of beta-lactams resulted as protective factor. The risk of bias was moderate in 19 studies and severe in the other 2.

CONCLUSIONS

Attaining aggressive beta-lactams PK/PD targets provided significant clinical benefits in critical patients. Our analysis could be useful to stratify patients at high-risk of failure in attaining aggressive PK/PD targets.

Assessment of the practical impact of adjusting beta-lactam dosages based on therapeutic drug monitoring in critically ill adult patients: a systematic review and meta-analysis of randomized clinical trials and observational studies

An estimated 70% of critically ill patients receive antibiotics, most frequently beta-lactams. The pharmacokinetic properties of these substances in this patient population are poorly predictable. Therapeutic drug monitoring (TDM) is helpful in making personalized decisions in this field, but its overall impact as a clinical decision-supporting tool is debated. We aimed to evaluate the clinical implications of adjusting beta-lactam dosages based on TDM in the critically ill population by performing a systematic review and meta-analysis of available investigations. Randomized controlled trials and observational studies were retrieved by searching three major databases. The intervention group received TDM-guided beta-lactam treatment, that is, at least one dose reconsideration based on the result of the measurement of drug concentrations, while TDM-unadjusted dosing was employed in the comparison group. The outcomes were evaluated using forest plots with random-effects modeling and subgroup analysis. Eight eligible studies were identified, including 1044 patients in total. TDM-guided beta-lactam treatment was associated with improved clinical cure from infection [odds ratio (OR): 2.22 (95% confidence interval (CI): 1.78-2.76)] and microbiological eradication [OR: 1.72 (CI: 1.05-2.80)], as well as a lower probability of treatment failure [OR: 0.47 (CI: 0.36-0.62)], but the heterogeneity of studies was remarkably high, especially in terms of mortality (70%). The risk of bias was moderate. While the TDM-guided administration of beta-lactams to critically ill patients has a favorable impact, standardized study designs and larger sample sizes are required for developing evidence-based protocols in this field.

Exposure levels and target attainment of piperacillin/tazobactam in adult patients admitted to the intensive care unit: a prospective observational study

PURPOSE

The objective of this study was to evaluate the exposure and the pharmacodynamic target attainment of piperacillin/tazobactam (PTZ) in adult critically ill patients.

METHODS

We conducted a prospective observational study in the intensive care unit (ICU) of the Hôpital du Sacré-Cœur de Montréal (a Level I trauma centre in Montreal, QC, Canada) between January 2021 and June 2022. We included patients aged 18 yr or older admitted to the ICU who received PTZ by intravenous administration. Demographic and clinical characteristics were collected, and clinical scores were calculated. On study day 1 of antimicrobial therapy, three blood samples were collected at the following timepoints: one hour after PTZ dose administration and at the middle and at the end of the dosing interval. The sampling schedule was repeated on days 4 and 7 of therapy if possible. Samples were analyzed by ultra-high performance liquid chromatography with diode array detector to determine the total piperacillin concentration. Middle- and end-of-interval concentrations were used for target attainment analyses, and were defined as a concentration above the minimal inhibitory concentration of 16 mg·L-1, corresponding to the breakpoint of Enterobacteriaceae and Pseudomonas aeruginosa.

RESULTS

Forty-three patients were recruited and 202 blood samples were analyzed. The most prevalent dose was 3/0.375 g every six hours (n = 50/73 doses administered, 68%) with a 30-min infusion. We observed marked variability over the three sampling timepoints, and the median [interquartile range] piperacillin concentrations at peak, middle of interval, and end of interval were 109.4 [74.0-152.3], 59.3 [21.1-74.4], and 25.3 [6.8-44.6] mg·L-1, respectively. When assessing target attainment, 37% of patients did not reach the efficacy target of a trough concentration of 16 mg·L-1. The majority of patients who were underexposed were patients with normal to augmented renal clearance.

CONCLUSION

In this prospective observational study of adult ICU patients receiving intravenous PTZ, a large proportion had subtherapeutic concentrations of piperacillin. This was most notable in patients with normal to augmented renal clearance. More aggressive dosage regimens may be required for this subpopulation to ensure attainment of efficacy targets.

Meropenem pharmacokinetic/pharmacodynamic target attainment and clinical response in ICU patients: A prospective observational study

BACKGROUND

Several studies report lack of meropenem pharmacokinetic/pharmacodynamic (PK/PD) target attainment (TA) and risk of therapeutic failure with intermittent bolus infusions in intensive care unit (ICU) patients. The aim of this study was to describe meropenem TA in an ICU population and the clinical response in the first 72 h after therapy initiation.

METHODS

A prospective observational study of ICU patients ≥18 years was conducted from 2014 to 2017. Patients with normal renal clearance (NRC) and augmented renal clearance (ARC) and patients on continuous renal replacement therapy (CRRT) were included. Meropenem was administered as intermittent bolus infusions, mainly at a dose of 1 g q6h. Peak, mid, and trough levels were sampled at 24, 48, and 72 h after therapy initiation. TA was defined as 100% T > 4× MIC or trough concentration above 4× MIC. Meropenem PK was estimated using traditional calculation methods and population pharmacokinetic modeling (P-metrics®). Clinical response was evaluated by change in C-reactive protein (CRP), Sequential Organ Failure Assessment (SOFA) score, leukocyte count, and defervescence.

RESULTS

Eighty-seven patients were included, with a median Simplified Acute Physiology (SAPS) II score 37 and 90 days mortality rate of 32%. Median TA was 100% for all groups except for the ARC group with 45.5%. Median CRP fell from 175 (interquartile range [IQR], 88-257) to 70 (IQR, 30-114) (p < .001) in the total population. A reduction in SOFA score was observed only in the non-CRRT groups (p < .001).

CONCLUSION

Intermittent meropenem bolus infusion q6h gives satisfactory TA in an ICU population with variable renal function and CRRT modality, except for ARC patients. No consistent relationship between TA and clinical endpoints were observed.

Prospective assessment of the frequency of and risk factors for bleeding events in patients treated with cefazolin

PURPOSE

Major bleedings have been described with cefazolin. The objective was to determine the frequency of bleeding events in cefazolin-treated patients and to identify risk factors for these complications.

METHODS

Monocenter prospective observational study of all consecutive cefazolin-treated patients. Patients benefited from a daily clinical assessment of bleedings and a twice-a-week blood sampling including hemostasis. Bleedings were classified according to the International Society on Thrombosis and Hemostasis classification: major, clinically relevant non-major bleedings (CRNMB) and minor bleedings.

RESULTS

From September 2019 to July 2020, 120 patients were included, with a mean age of 59.4 (± 20.7) years; 70% of them (84/120) were men. At least 1 CRNMB or major bleeding were observed in 10% of the patients (12/120). Compared to patients with no or minor bleeding, patients with CRNMB or major bleeding were, upon start of cefazolin, more frequently hospitalized in an intensive care unit (7/12, 58.3%, vs. 12/108, 11.1%, P < 0.001, respectively) and receiving vitamin K antagonists (4/12, 33.3%, vs. 8/108, 7.4%, P = 0.019, respectively). After multivariate analysis, patients receiving vitamin K antagonists the day prior bleeding and/or treated for endocarditis were factors associated with an increased risk of CRNMB or major bleeding (odd ratio 1.36, confidence interval 95%, 1.06-1.76, P = 0.020 and 1.30, 1.06-1.61, P = 0.015, respectively).

CONCLUSIONS

Bleeding events associated with cefazolin treatment are frequent. Close clinical monitoring should be performed for patients treated for endocarditis and/or receiving vitamin K antagonists. Hemostasis work-up could be restricted to these patients.

Clinical evaluation of the BioFire Respiratory Pathogen Panel for the guidance of empirical antimicrobial therapy in critically ill patients with hospital-acquired pneumonia: A multicenter, quality improvement project

BACKGROUND

We aimed to determine whether implementing antimicrobial stewardship based on multiplex bacterial PCR examination of respiratory fluid can enhance outcomes of critically ill patients with hospital-acquired pneumonia (HAP).

METHODS

We conducted a quality improvement study in two hospitals in France. Adult patients requiring invasive mechanical ventilation with a diagnosis of HAP were included. In the pre-intervention period (August 2019 to April 2020), antimicrobial therapy followed European guidelines. In the «intervention» phase (June 2020 to October 2021), treatment followed a multiplex PCR-guided protocol. The primary endpoint was a composite endpoint made of mortality on day 28, clinical cure between days 7 and 10, and duration of invasive mechanical ventilation on day 28. The primary outcome was analyzed with a DOOR strategy.

RESULTS

A total of 443 patients were included in 3 ICUs from 2 hospitals (220 pre-intervention; 223 intervention). No difference in the ranking of the primary composite outcome was found (DOOR: 50.3%; 95%CI, 49.9%-50.8%). The number of invasive mechanical ventilation-free days at day 28 was 10.0 [0.0; 19.0] in the baseline period and 9.0 [0.0; 20.0] days during the intervention period (p = 0.95). The time-to-efficient antimicrobial treatment was 0.43 ± 1.29 days before versus 0.55 ± 1.13 days after the intervention (p = 0.56).

CONCLUSION

Implementation of Rapid Multiplex PCR to guide empirical antimicrobial therapy for critically ill patients with HAP was not associated with better outcomes. However, adherence to stewardship was low, and the study may have had limited power to detect a clinically important difference.

Dosing Regimen for Cefotaxime Should Be Adapted to the Stage of Renal Dysfunction in Critically Ill Adult Patients-A Retrospective Study

Cefotaxime administration is recommended in doses of 3-12 g/day in adults with a Glomerular Filtration Rate (GFR) > 5 mL/min. This study aimed to assess the impact of renal function and obesity on cefotaxime concentrations in intensive care unit (ICU) patients. A retrospective cohort study was conducted on consecutive ICU patients receiving continuous cefotaxime infusion between 2020 and 2022 [IRBN992021/CHUSTE]. Doses were not constant; consequently, a concentration-to-dose ratio (C/D) was considered. Statistical analysis was performed to assess the relationship between cefotaxime concentrations, renal function, and obesity. A total of 70 patients, median age 61 years, were included, with no significant difference in cefotaxime concentrations between obese and non-obese patients. However, concentrations varied significantly by GFR, with underdosing prevalent in patients with normal to increased renal function and overdosing in those with severely impaired renal function. Adjustment of cefotaxime dosing according to GFR was associated with improved target attainment. Cefotaxime dosing in critically ill patients should consider renal function, with higher initial doses required in patients with normal to increased GFR and lower doses in those with severely impaired renal function. Therapeutic drug monitoring may aid in optimising dosing regimens. Prospective studies are warranted to validate these findings and inform clinical practice.

Comparative Impact of an Optimized PK/PD Target Attainment of Piperacillin-Tazobactam vs. Meropenem on the Trend over Time of SOFA Score and Inflammatory Biomarkers in Critically Ill Patients Receiving Continuous Infusion Monotherapy for Treating Documented Gram-Negative BSIs and/or VAP

(1) Background: The advantage of using carbapenems over beta-lactam/beta-lactamase inhibitor combinations in critically ill septic patients still remains a debated issue. We aimed to assess the comparative impact of an optimized pharmacokinetic/pharmacodynamic (PK/PD) target attainment of piperacillin-tazobactam vs. meropenem on the trend over time of both Sequential Organ Failure Assessment (SOFA) score and inflammatory biomarkers in critically ill patients receiving continuous infusion (CI) monotherapy with piperacillin-tazobactam or meropenem for treating documented Gram-negative bloodstream infections (BSI) and/or ventilator-associated pneumonia (VAP). (2) Methods: We performed a retrospective observational study comparing critically ill patients receiving targeted treatment with CI meropenem monotherapy for documented Gram-negative BSIs or VAP with a historical cohort of critical patients receiving CI piperacillin-tazobactam monotherapy. Patients included in the two groups were admitted to the general and post-transplant intensive care unit in the period July 2021-September 2023 and fulfilled the same inclusion criteria. The delta values of the SOFA score between the baseline of meropenem or piperacillin-tazobactam treatment and those at 48-h (delta 48-h SOFA score) or at 7-days (delta 7-days SOFA) were selected as primary outcomes. Delta 48-h and 7-days C-reactive protein (CRP) and procalcitonin (PCT), microbiological eradication, resistance occurrence, clinical cure, multi-drug resistant colonization at 90-day, ICU, and 30-day mortality rate were selected as secondary outcomes. Univariate analysis comparing primary and secondary outcomes between critically ill patients receiving CI monotherapy with piperacillin-tazobactam vs. meropenem was carried out. (3) Results: Overall, 32 critically ill patients receiving CI meropenem monotherapy were compared with a historical cohort of 43 cases receiving CI piperacillin-tazobactam monotherapy. No significant differences in terms of demographics and clinical features emerged at baseline between the two groups. Optimal PK/PD target was attained in 83.7% and 100.0% of patients receiving piperacillin-tazobactam and meropenem, respectively. No significant differences were observed between groups in terms of median values of delta 48-h SOFA (0 points vs. 1 point; p = 0.89) and median delta 7-days SOFA (2 points vs. 1 point; p = 0.43). Similarly, no significant differences were found between patients receiving piperacillin-tazobactam vs. meropenem for any of the secondary outcomes. (4) Conclusion: Our findings may support the contention that in critically ill patients with documented Gram-negative BSIs and/or VAP, the decreases in the SOFA score and in the inflammatory biomarkers serum levels achievable with CI piperacillin-tazobactam monotherapy at 48-h and at 7-days may be of similar extent and as effective as to those achievable with CI meropenem monotherapy provided that optimization on real-time by means of a TDM-based expert clinical pharmacological advice program is granted.

Determination of meropenem in capillary plasma microsamples using LC-MS/MS

Background: The measurement of meropenem plasma concentrations is employed for dosing regimen individualization. The aim of this study was to develop and validate a LC-MS/MS assay for quantification of meropenem in capillary plasma microsamples. Methods: Samples were prepared by protein precipitation with acetonitrile, followed by clean-up with dichloromethane. The method was validated and applied to 12 paired samples of venous and capillary plasma. Results: The method was linear in the range of 0.5-50 μg/ml. Matrix effects were minimal. Inter- and intra-assay were 3.8-7.9% and 2.7-5.5%, respectively, while accuracy was 91.7-100.6%. Concentrations in capillary and venous plasma were highly correlated. Conclusion: An assay for the quantification of meropenem in capillary plasma microsamples was fully validated, showing potential for clinical application.

Infectious Pulmonary Diseases

Pneumonia is a lower respiratory tract infection caused by the inability to clear pathogens from the lower airway and alveoli. Cytokines and local inflammatory markers are released, causing further damage to the lungs through the accumulation of white blood cells and fluid congestion, leading to pus in the parenchyma. The Infectious Diseases Society of America defines pneumonia as the presence of new lung infiltrate with other clinical evidence supporting infection, including new fever, purulent sputum, leukocytosis, and decline in oxygenation. Importantly, lower respiratory infections remain the most deadly communicable disease. Pneumonia is subdivided into three categories: (1) community acquired, (2) hospital acquired, and (3) ventilator associated. Therapy for each differs based on the severity of the disease and the presence of risk factors for methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa.

Therapeutic drug monitoring of imipenem/cilastatin and meropenem in critically ill adult patients

OBJECTIVES

To investigate the factors influencing imipenem/cilastatin (IMI) and meropenem (MEM) concentrations in critically ill adult patients and the role of these concentrations in the clinical outcome.

METHODS

Plasma trough concentrations of IMI and MEM were detected by high-performance liquid chromatography. A target value of 100%-time above MIC was used for the drugs.

RESULTS

A total of 186 patients were included, with 87 receiving IMI and 99 receiving MEM. The percentages of patients reaching the target IMI and MEM concentrations were 44.8% and 38.4%, respectively. The proportions of patients infected with drug-resistant bacteria were 57.5% and 69.7% in the IMI group and MEM group, respectively. In the multivariate analysis, the risk factors for an IMI concentration that did not reach the target were infection with drug-resistant bacteria, and those for MEM were infection with drug-resistant bacteria, estimated glomerular filtration rate, and diabetes mellitus. A total of 47.1% of patients had good outcomes in the IMI cohort, and 38.1% of patients had good outcomes in the MEM cohort. The duration of mechanical ventilation and IMI concentration were associated with ICU stay in patients in the IMI cohort, while MEM concentration and severe pneumonia affected the clinical outcome of patients in the MEM cohort.

CONCLUSION

Infection with drug-resistant bacteria is an important factor influencing whether IMI and MEM concentrations reach the target. Furthermore, IMI and MEM concentrations are associated with the clinical outcome, and elevated doses of IMI and MEM should be given to patients who are infected with drug-resistant bacteria.

Efficacy of Continuous vs. Intermittent Administration of Cefepime in Adult ICU Patients with Gram-Negative Bacilli Bacteremia: A Randomized Double-Blind Clinical Study

INTRODUCTION

The objective of this study was to compare the continuous infusion of cefepime with the intermittent infusion in patients with sepsis caused by Gram-negative bacilli (GNB).

METHODS

Randomized 1:1 multicenter double-blinded placebo-controlled study with allocation concealment; multicenter study in the intensive care units of Colombia. Patients with sepsis, severe sepsis or septic shock, and GNB-suspected bacteremia. Cefepime was administered for 7 to 14 days over 30 m intermittently every 8 h over 24 h plus continuous saline solution (0.9%) (G1) or 3 g administered continuously plus saline solution every 8 h (0.9%) (G2). The percentage of clinical response at 3, 7, and 14 days, relapse at 28 days, and mortality at discharge were measured.

RESULTS

The recruitment was stopped at the suggestion of the Institutional Review Board (IRB) following an FDA alert about cefepime. Thirty-two patients were randomized; 25 received the intervention, and GNB bacteremia was confirmed in 16 (9 G1 and 7 G2). Favorable clinical response in days 3, 7, and 14 was 88.8%, 88.8%, and 77.8% (G1) and was similar for G2 (85.7%). There were no relapses or deaths in G2, while in G1, one relapse and two deaths were observed.

CONCLUSIONS

The results of this study support the use of cefepime for the treatment of Gram-negative infections in critically ill patients, but we could not demonstrate differences between continuous or intermittent administration because of the small sample size, given the early suspension of the study.

Antibiotic dosing recommendations in critically ill patients receiving new innovative kidney replacement therapy

BACKGROUND

The Tablo Hemodialysis System is a new innovative kidney replacement therapy (KRT) providing a range of options for critically ill patients with acute kidney injury. The use of various effluent rate and treatment durations/frequencies may clear antibiotics differently than traditional KRT. This Monte Carlo Simulation (MCS) study was to develop antibiotic doses likely to attain therapeutic targets for various KRT combinations.

METHODS

Published body weights and pharmacokinetic parameter estimates were used to predict drug exposure for cefepime, ceftazidime, imipenem, meropenem and piperacillin/tazobactam in virtual critically ill patients receiving five KRT regimens. Standard free β-lactam plasma concentration time above minimum inhibitory concentration targets (40-60%fT> MIC and 40-60%fT> MICx4) were used as efficacy targets. MCS assessed the probability of target attainment (PTA) and likelihood of toxicity for various antibiotic dosing strategies. The smallest doses attaining PTA ≥ 90% during 1-week of therapy were considered optimal.

RESULTS

MCS determined β-lactam doses achieving ∼90% PTA in all KRT options. KRT characteristics influenced antibiotic dosing. Cefepime and piperacillin/tazobactam regimens designed for rigorous efficacy targets were likely to exceed toxicity thresholds.

CONCLUSION

The flexibility offered by new KRT systems can influence β-lactam antibiotic dosing, but doses can be devised to meet therapeutic targets. Further clinical validations are warranted.

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.

Simultaneous determination of oxacillin and cloxacillin in plasma and CSF using turbulent flow liquid chromatography coupled to high-resolution mass spectrometry: Application in therapeutic drug monitoring

Cloxacillin and oxacillin are group M penicillins. The therapeutic monitoring of plasma concentrations of these antibiotics and those of their hydroxymethylated metabolites is of great clinical interest, especially in the choice of an adequate dosage allowing an effective treatment while limiting the occurrence of undesirable effects and the development of bacterial resistance. In this context, we conducted this work aiming at developing and validating a method allowing the determination of cloxacillin and oxacillin as well as the identification of their active metabolites in different biological matrices (CSF and plasma) using turbulent flow liquid chromatography coupled to high-resolution mass spectrometry. To do this, we carried out several optimisation tests. Subsequently, we validated our method according to the latest bioanalytical validation recommendations of the European Medicines Agency. The validation results showed that our method is specific and sensitive. We obtained good linearity in the range 0.5 to 100 µg/mL with correlation coefficients above 0.995. The lower limit of quantification was 0.5 µg/mL for each analyte. The method was found to be accurate with repeatability and reproducibility coefficients of variation below 15 %. Our method is also accurate with bias values below 15 %. Recovery values ranged from 87 % to 95 %. Finally, we were able to apply our method to the therapeutic monitoring of the analysed molecules and to identify their active metabolites. Our results suggest that LC-MS shows superiority in the therapeutic monitoring of these antibiotics due to the superiority of specificity shown by this method. This assay method can be routinely used for the daily plasma assays of patients treated with these antibiotics in the context of therapeutic monitoring.

New Antibiotics Against Multidrug-Resistant Gram-Negative Bacteria in Liver Transplantation: Clinical Perspectives, Toxicity, and PK/PD Properties

Antimicrobial resistance is a growing global health problem, and it is especially relevant among liver transplant recipients where infections, particularly when caused by microorganisms with a difficult-to-treat profile, are a significant cause of morbidity and mortality. We provide here a complete dissection of the antibiotics active against multidrug-resistant Gram-negative bacteria approved over the last years, focusing on their activity spectrum, toxicity profile and PK/PD properties, including therapeutic drug monitoring, in the setting of liver transplantation. Specifically, the following drugs are presented: ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, cefiderocol, and eravacycline. Overall, studies on the safety and optimal employment of these drugs in liver transplant recipients are limited and especially needed. Nevertheless, these pharmaceuticals have undeniably enhanced therapeutic options for infected liver transplant recipients.

Two-dimensional liquid chromatography measurement of meropenem concentration in synovial fluid of patients with periprosthetic joint infection

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery. One potential treatment approach for PJI could be the combination of one-stage revision and intra-articular infusion of antibiotics. Meropenem is one of the commonly used intra-articular antibiotics in our institution. Determining the concentration of meropenem in the joint cavity could be crucial for optimizing its local application, effectively eradicating biofilm infection, and improving PJI treatment outcomes. In this study, we developed a simple, precise, and accurate method of two-dimensional liquid chromatography (2D-LC) for determining the concentration of meropenem in human synovial fluid. The method was then validated based on the guidelines of the Food and Drug Administration and the Chinese Pharmacopoeia. Meropenem showed good linearity in the range of 0.31-25.01 μg/mL (r ≥ .999). Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, and stability validation results were all within the acceptance range. This method has been successfully applied to the determination of synovial fluid samples from PJI patients, providing a useful detection method for meropenem therapeutic drug monitoring (TDM) in PJI patients.

A descriptive pharmacokinetic/pharmacodynamic analysis of ceftazidime-avibactam in a case series of critically ill patients with augmented renal clearance

To describe the pharmacokinetics/pharmacodynamics (PK/PD) of a 2 h infusion of ceftazidime-avibactam (CAZ-AVI) in critically ill patients with augmented renal clearance (ARC). A retrospective review of all critically ill patients with ARC who were treated with CAZ-AVI between August 2020 and May 2023 was conducted. Patients whose 12-h creatinine clearance prior to CAZ-AVI treatment and steady-state concentration (Css) of CAZ-AVI were both monitored were enrolled. The free fraction (fCss) of CAZ-AVI was calculated from Css. The joint PK/PD targets of CAZ-AVI were considered optimal when a Css/minimum inhibitory concentration (MIC) ratio for CAZ ≥4 (equivalent to 100% fT > 4 MIC) and a Css/CT ratio of AVI >1 (equivalent to 100% fT > CT 4.0 mg/L) were reached simultaneously, quasioptimal when only one of the two targets was reached, and suboptimal when neither target was reached. The relationship between PK/PD goal achievement, microbial eradication and the clinical efficacy of CAZ-AVI was evaluated. Four patients were included. Only one patient achieved optimal joint PK/PD targets, while the other three reached suboptimal targets. The patient with optimal PK/PD targets achieved microbiological eradication, while the other three patients did not, but all four patients achieved good clinical efficacy. Standard dosages may not enable most critically ill patients with ARC to reach the optimal joint PK/PD targets of CAZ-AVI. Optimal drug dose adjustment of CAZ-AVI in ARC patients requires dynamic drug concentration monitoring.

Ceftazidime-avibactam induced renal disorders: past and present

With the increasing prevalence of multidrug-resistant Gram-negative bacterial pathogens worldwide, antimicrobial resistance has become a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) exhibited excellent in vitro activity against many carbapenemase-producing pathogens, and was widely used for the treatment of various complicated infections. CAZ-AVI is well tolerated across all dosing regimens, and its associated acute kidney injury (AKI) in phase II/III clinical trials is rare. However, recent real-world studies have demonstrated that CAZ-AVI associated AKI was more frequent in real-world than in phase II and III clinical trials, particularly in patients receiving concomitant nephrotoxic agents, with critically ill patients being at a higher risk. Herein, we reviewed the safety data related to renal impairment of CAZ-AVI, and discussed its pharmacokinetic/pharmacodynamic targets and dosage adjustment in patients with impaired renal function. This review aimed to emphasize the importance for healthcare professionals to be aware of this adverse event of CAZ-AVI and provide practical insights into the dosage optimization in critically ill patients with renal dysfunction.

Sepsis Stewardship: The Puzzle of Antibiotic Therapy in the Context of Individualization of Decision Making

The main recent change observed in the field of critical patient infection has been universal awareness of the need to make better use of antimicrobials, especially for the most serious cases, beyond the application of simple and effective formulas or rigid protocols. The increase in resistant microorganisms, the quantitative increase in major surgeries and interventional procedures in the highest risk patients, and the appearance of a significant number of new antibiotics in recent years (some very specifically directed against certain mechanisms of resistance and others with a broader spectrum of applications) have led us to shift our questions from "what to deal with" to "how to treat". There has been controversy about how best to approach antibiotic treatment of complex cases of sepsis. The individualized and adjusted dosage, the moment of its administration, the objective, and the selection of the regimen are pointed out as factors of special relevance in a critically ill patient where the frequency of resistant microorganisms, especially among the Enterobacterales group, and the emergence of multiple and diverse antibiotic treatment alternatives have made the appropriate choice of antibiotic treatment more complex, requiring a constant updating of knowledge and the creation of multidisciplinary teams to confront new infections that are difficult to treat. In this article, we have reviewed the phenomenon of the emergence of resistance to antibacterials and we have tried to share some of the ideas, such as stewardship, sparing carbapenems, and organizational, microbiological, pharmacological, and knowledge tools, that we have considered most useful and effective for individualized decision making that takes into account the current context of multidrug resistance. The greatest challenge, therefore, of decision making in this context lies in determining an effective, optimal, and balanced empirical antibiotic treatment.

Personalized application of antimicrobial drugs in pediatric patients with augmented renal clearance: a review of literature

The effect of renal functional status on drug metabolism is a crucial consideration for clinicians when determining the appropriate dosage of medications to administer. In critically ill patients, there is often a significant increase in renal function, which leads to enhanced drug metabolism and potentially inadequate drug exposure. This phenomenon, known as augmented renal clearance (ARC), is commonly observed in pediatric critical care settings. The findings of the current study underscore the significant impact of ARC on the pharmacokinetics and pharmacodynamics of antimicrobial drugs in critically ill pediatric patients. Moreover, the study reveals a negative correlation between increased creatinine clearance and blood concentrations of antimicrobial drugs. The article provides a comprehensive review of ARC screening in pediatric patients, including its definition, risk factors, and clinical outcomes. Furthermore, it summarizes the dosages and dosing regimens of commonly used antibacterial and antiviral drugs for pediatric patients with ARC, and recommendations are made for dose and infusion considerations and the role of therapeutic drug monitoring.

CONCLUSION

 ARC impacts antimicrobial drugs in pediatric patients.

WHAT IS KNOWN

• ARC is inextricably linked to the failure of antimicrobial therapy, recurrence of infection, and subtherapeutic concentrations of drugs.

WHAT IS NEW

• This study provides an updated overview of the influence of ARC on medication use and clinical outcomes in pediatric patients. • In this context, there are several recommendations for using antibiotics in pediatric patients with ARC: 1) increase the dose administered; 2) prolonged or continuous infusion administration; 3) use of TDM; and 4) use alternative drugs that do not undergo renal elimination.

[Guideline-conform treatment of sepsis]

The time to administration of broad-spectrum antibiotics and (secondarily) to the initiation of hemodynamic stabilization are the most important factors influencing survival of patients with sepsis and septic shock; however, the basic prerequisite for the initiation of an adequate treatment is that a suspected diagnosis of sepsis is made first. Therefore, the treatment of sepsis, even before it has begun, is an interdisciplinary and interprofessional task. This article provides an overview of the current state of the art in sepsis treatment and points towards new evidence that has the potential to change guideline recommendations in the coming years. In summary, the following points are critical: (1) sepsis must be diagnosed as soon as possible and the implementation of a source control intervention (in case of a controllable source) has to be implemented as soon as (logistically) possible. (2) In general, intravenous broad-spectrum antibiotics should be given within the first hour after diagnosis if sepsis or septic shock is suspected. In organ dysfunction without shock, where sepsis is a possible but unlikely cause, the results of focused advanced diagnostics should be awaited before a decision to give broad-spectrum antibiotics is made. If it is not clear within 3 h whether sepsis is the cause, broad-spectrum antibiotics should be given when in doubt. Administer beta-lactam antibiotics as a prolonged (or if therapeutic drug monitoring is available, continuous) infusion after an initial loading dose. (3) Combination treatment with two agents for one pathogen group should remain the exception (e.g. multidrug-resistant gram-negative pathogens). (4) In the case of doubt, the duration of anti-infective treatment should rather be shorter than longer. Procalcitonin can support the clinical decision to stop (not to start!) antibiotic treatment! (5) For fluid treatment, if hypoperfusion is present, the first (approximately) 2L (30 ml/kg BW) of crystalloid solution is usually safe and indicated. After that, the rule is: less is more! Any further fluid administration should be carefully weighed up with the help of dynamic parameters, the patient's clinical condition and echo(cardio)graphy.

Efficacy of combination therapy with standard-dose carbapenem for treating nosocomial pneumonia caused by carbapenem-resistant Acinetobacter baumannii in intensive care units: A multicentre retrospective propensity score-matched study

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is common worldwide. Despite carbapenem resistance, standard-dose carbapenems are still used in clinical practice. Hence in this study, we aimed to compare the efficacy and outcomes of a regimen containing standard-dose carbapenems with those of a regimen lacking carbapenems during the treatment of critically ill patients with CRAB nosocomial pneumonia in the intensive care unit (ICU). Initially, 735 patients were recruited for this multicentre retrospective cohort study. After exclusion, time-window bias adjustment, and propensity score matching, multiple clinical outcomes were compared between the carbapenem-containing (CC) (n = 166) and no carbapenem-containing (NCC) (n = 166) groups. The CC group showed a higher risk of clinical failure on day 7 than the NCC group (44.6% vs. 33.1%, P = 0.043). The lengths of ICU stay (21 and 16 days, P = 0.024) and hospital stay (61 and 44 days, P = 0.003) were longer in the CC group than in the NCC group. Multivariate analysis showed that the CC regimen was associated with higher clinical failure (adjusted odds ratio (aOR) = 1.64, 95% CI = 1.05-2.56, P = 0.031) and lower microbiological eradication (aOR = 0.48, 95% CI = 0.23-1.00, P = 0.049) at day 7 than the NCC group. Thus, a regimen containing a standard dose of carbapenem should be prescribed with caution for treating CRAB nosocomial pneumonia in the ICU.

Potential benefits of therapeutic drug monitoring for beta-lactam antibiotics in augmented renal clearance patients: a case report

Augmented renal clearance (ARC) is commonly described in critically ill patients, making drug pharmacokinetics even harder to predict in this population. This case report displays the value of therapeutic drug monitoring (TDM) of piperacillin/tazobactam (PTZ) in this population. We identified two patients with ARC and intermittent administration of PTZ who took part in a prospective, descriptive study conducted at Hôpital du Sacré-Cœur de Montréal. Both had plasma samples drawn at peak, middle, and end of their dosing intervals of PTZ. Minimal inhibitory concentrations (MICs) of 4 and 8 mg/L were chosen to evaluate therapeutic target attainment at middle and end of dosing interval. The first patient was a 52-year-old male with a renal clearance rate estimated at 147 mL/min who received 3.375 g PTZ every 6 h. The second patient, a 49-year-old male, had an estimated renal clearance rate of 163 mL/min and received the same regimen. Both patients had piperacillin concentrations above the target MICs at middle of the dosing interval, but they failed to reach a trough concentration above 8 mg/L. The present case report showcases two patients with subtherapeutic PTZ concentrations despite strict following of local administration protocols. This suboptimal administration could not only lead to treatment failure, but also to the selection and growth of resistant pathogens. Implementing TDM would offer the possibility to adjust drug regimens in real-time and prevent situations like these from occurring.

Clinical efficacy of ceftazidime/avibactam combination therapy for severe hospital-acquired pulmonary infections caused by carbapenem-resistant and difficult-to-treat Pseudomonas aeruginosa

OBJECTIVES

This retrospective study aimed to identify the effectiveness of ceftazidime/avibactam (CAZ/AVI) and its optimisation programs for severe hospital-acquired pulmonary infections (sHAPi) caused by carbapenem-resistant and difficult-to-treat Pseudomonas aeruginosa (CRPA and DTR-P. aeruginosa).

METHODS

We retrospectively analysed observational data on treatment and outcomes of CAZ/AVI for sHAPi caused by CRPA or DTR-P. aeruginosa. The primary study outcomes were to evaluate the clinical and microbiology efficacy of CAZ/AVI.

RESULTS

The cohort consisted of 84 in-patients with sHAPi caused by CRPA (n = 39) and DTR-P. aeruginosa (n = 45) who received at least 72 h of CAZ/AVI therapy. The clinical cure rate was 63.1% in total. There was no significant difference in study outcomes between patients treated with CAZ/AVI monotherapy and those managed with combination regimens. CAZ/AVI as first-line therapy possessed prominent clinical benefits regarding infections caused by DTR-P. aeruginosa. The clinical cure rate was positively relevant with loading dose for CAZ/AVI (odds ratio [OR] 0.03; 95% confidence interval [CI] 0.004-0.19; P < 0.001) and with CAZ/AVI administration by prolonged infusion (odds ratio 0.15; 95% confidence interval 0.03-0.77; P = 0.002). APACHE II score>15 (P = 0.013), septic shock at infection onset (P = 0.001), and CAZ/AVI dose adjustment for renal dysfunction (P = 0.003) were negative predictors of clinical cure.

CONCLUSION

CAZ/AVI is a valid alternative for sHAPi caused by CPRA and DTR-P. aeruginosa, even when used alone. Optimisations of the treatment with CAZ/AVI in critically ill patients, including loading dose, adequate maintenance dose and prolonged infusion, were positively associated with potential clinical benefits.

Systematic review of room temperature stability of key beta-lactam antibiotics for extended infusions in inpatient settings

BACKGROUND

Extended infusion (EI) of beta-lactam antibiotics may offer clinical benefits aligned with improved probability of target attainment for critical pharmacokinetic/pharmacodynamic parameters that correlate with efficacy. There is much research interest in prolonged and continuous infusions (collectively, extended infusions) of beta-lactams to improve patient outcomes, particularly in critically ill patients in intensive care. While definitive clinical trial data demonstrating beneficial outcomes is awaited, there has been limited focus on the stability of the agents given by EI, which may be an equally critical parameter. EI may allow for savings in nursing time due to reduced need for drug reconstitution. We set out to examine the data for stability for EI at room temperature, consistent with the requirements of 'A Standard Protocol for Deriving and Assessment of Stability- Part 1 Aseptic Preparation (Small Molecules)', which allows a 5% loss of active pharmaceutical ingredient (API) applicable for those territories that use the British Pharmacopoeia also for a 10% loss applicable in much of rest of the world.

METHODS

Searches using preferred reporting items for systematic reviews and meta-analyses (PRISMA) principles for stability data on freshly prepared beta-lactam antimicrobials for extended administration at room temperature (at or above 23°C) were conducted in November 2021 and updated in December 2022.

RESULTS

We found data to support the extension of the shelf life of 12 key beta-lactam antibiotics once reconstituted (aztreonam, amoxicillin, benzylpenicillin, flucloxacillin, piperacillin/tazobactam, cefazolin, cefmetazole, ceftaroline, ceftazidime, ceftriaxone, imipenem and meropenem) compliant with the NHS protocol, and data for five other agents (ticarcillin, cefepime, cefiderocol, cefoxitin and doripenem) which would be acceptable in regions outside the UK beyond that listed in the Summary of Product Characteristics.This review has not been registered under PROSPERO.

Impact of Beta-Lactam Target Attainment on Resistance Development in Patients with Gram-Negative Infections

BACKGROUND

The objective was to identify associations between beta-lactam pharmacokinetic/pharmacodynamic (PK/PD) targets and Gram-negative bacteria resistance emergence in patients.

METHODS

Retrospective data were collected between 2016 to 2019 at the University of Florida Health-Shands Hospital in Gainesville, FL. Adult patients with two Gram-negative isolates receiving cefepime, meropenem, or piperacillin-tazobactam and who had plasma beta-lactam concentrations were included. Beta-lactam exposures and time free drug concentrations that exceeded minimum inhibitory concentrations (ƒT > MIC), four multiples of MIC (ƒT > 4× MIC), and free area under the time concentration curve to MIC (ƒAUC/MIC) were generated. Resistance emergence was defined as any increase in MIC or two-fold increase in MIC. Multiple regression analysis assessed the PK/PD parameter impact on resistance emergence.

RESULTS

Two hundred fifty-six patients with 628 isolates were included. The median age was 58 years, and 59% were males. Cefepime was the most common beta-lactam (65%) and Pseudomonas aeruginosa the most common isolate (43%). The mean daily ƒAUC/MIC ≥ 494 was associated with any increase in MIC (p = 0.002) and two-fold increase in MIC (p = 0.004). The daily ƒAUC/MIC ≥ 494 was associated with decreased time on antibiotics (p = 0.008). P. aeruginosa was associated with any increase in MIC (OR: 6.41, 95% CI [3.34-12.28]) or 2× increase in MIC (7.08, 95% CI [3.56-14.07]).

CONCLUSIONS

ƒAUC/MIC ≥ 494 may be associated with decreased Gram-negative resistance emergence.

Towards optimization of ceftazidime dosing in obese ICU patients: the end of the 'one-size-fits-all' approach?

BACKGROUND

Ceftazidime is commonly used as a key antibiotic against Pseudomonas aeruginosa in critically ill patients. ICU patients have severely altered and variable antibiotic pharmacokinetics, resulting in lower antimicrobial concentrations and potentially poor outcome. Several factors, including obesity and renal function, may influence pharmacokinetics. Thus, the objective of the study was to evaluate the impact of obesity and renal function on ceftazidime plasma concentrations and dosing regimen in ICU patients.

METHODS

All consecutive adult patients from six ICUs, treated with continuous ceftazidime infusion and under therapeutic drug monitoring evaluation, were included. Obesity was defined as BMI ≥30 kg/m². Glomerular filtration rate (GFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration formula. The ceftazidime recommended target for plasma concentrations was between 35 and 80 mg/L.

RESULTS

A total of 98 patients (45 obese), with an average weight of 90 (±25) kg, were included. Mean GFR was 84.1 (±40.4) mL/min/1.73 m2. Recommended ceftazidime plasma concentrations were achieved for only 48.0% of patients, with median dosing regimen of 6 g/day. Obese patients had lower ceftazidime plasma concentrations compared with non-obese patients (37.8 versus 56.3 mg/L; P = 0.0042) despite similar dosing regimens (5.83 g/day versus 5.52 g/day, P = 0.2529). Almost all augmented renal clearance patients were underdosed despite ceftazidime dosing of 6.6 (±0.8) g/day. Weight-based ceftazidime dosing seemed to attenuate such obesity-related discrepancies, regardless of GFR.

CONCLUSIONS

Obese ICU patients required significantly greater ceftazidime doses to achieve the target range. A tailored dosing regimen may be considered based on weight and GFR. Future prospective studies should be performed to confirm this individualized dosing approach.