Longitudinal NGAL and cystatin C plasma profiles present a high level of heterogeneity in a mixed ICU population.

BACKGROUND: NGAL and Cystatin C (CysC) as biomarkers for the early detection of AKI are subject to both pathophysiological, as well as patient related heterogeneity. The aim of this study was to investigate the timeline of plasma levels of NGAL and CysC during the first seven days of ICU admission in a mixed ICU population and to relate these to AKI severity during ICU stay. Via these means we aimed to bring clarity to the previously reported heterogeneity of these renal biomarkers. METHODS: Prospective Observation Cohort. Consecutive patients admitted to adult ICU at an academic hospital in the Netherlands between 18-02-2014 and 31-03-2014 were included. Urine output, serum creatinine, plasma NGAL and CysC were recorded during the first seven days of ICU admission. Biomarker expression was analyzed based on KDIGO score and time of AKI diagnosis. RESULTS: 335 patients were included, 110 met KDIGO criteria for AKI. NGAL and CysC plasma levels were higher in AKI patients compared to non-AKI, high variability in individual values resulted in 56% of AKI patients having a false negative, and 32% of non-AKI patients having a false positive. Individual biomarker levels were variable, and no pattern based on KDIGO score was observed. CONCLUSIONS: Plasma NGAL and CysC as biomarkers for the early AKI detection may be subject to pathophysiological, and patient related heterogeneity. Further understanding of individual biomarker profiles may help in their application amongst mixed ICU populations. TRIAL REGISTRATION: The need for informed consent was waived by the Institutional Ethical Review Board of the University Medical Center Groningen (METc 2013 - 174) by Prof. dr. W.A. Kamps on May 17th 2013.

Development and evaluation of uncertainty quantifying machine learning models to predict piperacillin plasma concentrations in critically ill patients.

BACKGROUND: Beta-lactam antimicrobial concentrations are frequently suboptimal in critically ill patients. Population pharmacokinetic (PopPK) modeling is the golden standard to predict drug concentrations. However, currently available PopPK models often lack predictive accuracy, making them less suited to guide dosing regimen adaptations. Furthermore, many currently developed models for clinical applications often lack uncertainty quantification. We, therefore, aimed to develop machine learning (ML) models for the prediction of piperacillin plasma concentrations while also providing uncertainty quantification with the aim of clinical practice. METHODS: Blood samples for piperacillin analysis were prospectively collected from critically ill patients receiving continuous infusion of piperacillin/tazobactam. Interpretable ML models for the prediction of piperacillin concentrations were designed using CatBoost and Gaussian processes. Distribution-based Uncertainty Quantification was added to the CatBoost model using a proposed Quantile Ensemble method, useable for any model optimizing a quantile function. These models are subsequently evaluated using the distribution coverage error, a proposed interpretable uncertainty quantification calibration metric. Development and internal evaluation of the ML models were performed on the Ghent University Hospital database (752 piperacillin concentrations from 282 patients). Ensuing, ML models were compared with a published PopPK model on a database from the University Medical Centre of Groningen where a different dosing regimen is used (46 piperacillin concentrations from 15 patients.). RESULTS: The best performing model was the Catboost model with an RMSE and [Formula: see text] of 31.94-0.64 and 33.53-0.60 for internal evaluation with and without previous concentration. Furthermore, the results prove the added value of the proposed Quantile Ensemble model in providing clinically useful individualized uncertainty predictions and show the limits of homoscedastic methods like Gaussian Processes in clinical applications. CONCLUSIONS: Our results show that ML models can consistently estimate piperacillin concentrations with acceptable and high predictive accuracy when identical dosing regimens as in the training data are used while providing highly relevant uncertainty predictions. However, generalization capabilities to other dosing schemes are limited. Notwithstanding, incorporating ML models in therapeutic drug monitoring programs seems definitely promising and the current work provides a basis for validating the model in clinical practice.

Comparison of renal histopathology and gene expression profiles between severe COVID-19 and bacterial sepsis in critically ill patients.

BACKGROUND: The mechanisms driving acute kidney injury (AKI) in critically ill COVID-19 patients are unclear. We collected kidney biopsies from COVID-19 AKI patients within 30 min after death in order to examine the histopathology and perform mRNA expression analysis of genes associated with renal injury. METHODS: This study involved histopathology and mRNA analyses of postmortem kidney biopsies collected from patients with COVID-19 (n = 6) and bacterial sepsis (n = 27). Normal control renal tissue was obtained from patients undergoing total nephrectomy (n = 12). The mean length of ICU admission-to-biopsy was 30 days for COVID-19 and 3-4 days for bacterial sepsis patients. RESULTS: We did not detect SARS-CoV-2 RNA in kidney biopsies from COVID-19-AKI patients yet lung tissue from the same patients was PCR positive. Extensive acute tubular necrosis (ATN) and peritubular thrombi were distinct histopathology features of COVID-19-AKI compared to bacterial sepsis-AKI. ACE2 mRNA levels in both COVID-19 (fold change 0.42, p = 0.0002) and bacterial sepsis patients (fold change 0.24, p < 0.0001) were low compared to control. The mRNA levels of injury markers NGAL and KIM-1 were unaltered compared to control tissue but increased in sepsis-AKI patients. Markers for inflammation and endothelial activation were unaltered in COVID-19 suggesting a lack of renal inflammation. Renal mRNA levels of endothelial integrity markers CD31, PV-1 and VE-Cadherin did not differ from control individuals yet were increased in bacterial sepsis patients (CD31 fold change 2.3, p = 0.0006, PV-1 fold change 1.5, p = 0.008). Angiopoietin-1 mRNA levels were downregulated in renal tissue from both COVID-19 (fold change 0.27, p < 0.0001) and bacterial sepsis patients (fold change 0.67, p < 0.0001) compared to controls. Moreover, low Tie2 mRNA expression (fold change 0.33, p = 0.037) and a disturbed VEGFR2/VEGFR3 ratio (fold change 0.09, p < 0.0001) suggest decreased microvascular flow in COVID-19. CONCLUSIONS: In a small cohort of postmortem kidney biopsies from COVID-19 patients, we observed distinct histopathological and gene expression profiles between COVID-19-AKI and bacterial sepsis-AKI. COVID-19 was associated with more severe ATN and microvascular thrombosis coupled with decreased microvascular flow, yet minimal inflammation. Further studies are required to determine whether these observations are a result of true pathophysiological differences or related to the timing of biopsy after disease onset.

Caspofungin Weight-Based Dosing Supported by a Population Pharmacokinetic Model in Critically Ill Patients.

The objective of this study was to develop a population pharmacokinetic model and to determine a dosing regimen for caspofungin in critically ill patients. Nine blood samples were drawn per dosing occasion. Fifteen patients with (suspected) invasive candidiasis had one dosing occasion and five had two dosing occasions, measured on day 3 (±1) of treatment. Pmetrics was used for population pharmacokinetic modeling and probability of target attainment (PTA). A target 24-h area under the concentration-time curve (AUC) value of 98 mg·h/liter was used as an efficacy parameter. Secondarily, the AUC/MIC targets of 450, 865, and 1,185 were used to calculate PTAs for Candida glabrata, C. albicans, and C. parapsilosis, respectively. The final 2-compartment model included weight as a covariate on volume of distribution (V). The mean V of the central compartment was 7.71 (standard deviation [SD], 2.70) liters/kg of body weight, the mean elimination constant (Ke ) was 0.09 (SD, 0.04) h-1, the rate constant for the caspofungin distribution from the central to the peripheral compartment was 0.44 (SD, 0.39) h-1, and the rate constant for the caspofungin distribution from the peripheral to the central compartment was 0.46 (SD, 0.35) h-1 A loading dose of 2 mg/kg on the first day, followed by 1.25 mg/kg as a maintenance dose, was chosen. With this dose, 98% of the patients were expected to reach the AUC target on the first day and 100% of the patients on the third day. The registered caspofungin dose might not be suitable for critically ill patients who were all overweight (≥120 kg), over 80% of median weight (78 kg), and around 25% of lower weight (≤50 kg). A weight-based dose regimen might be appropriate for achieving adequate exposure of caspofungin in intensive care unit patients.

Continuous versus intermittent infusion of cefotaxime in critically ill patients: a randomized controlled trial comparing plasma concentrations.

BACKGROUND: In critical care patients, reaching optimal ß-lactam concentrations poses challenges, as infections are caused more often by microorganisms associated with higher MICs, and critically ill patients typically have an unpredictable pharmacokinetic/pharmacodynamic profile. Conventional intermittent dosing frequently yields inadequate drug concentrations, while continuous dosing might result in better target attainment. Few studies address cefotaxime concentrations in this population. OBJECTIVES: To assess total and unbound serum levels of cefotaxime and an active metabolite, desacetylcefotaxime, in critically ill patients treated with either continuously or intermittently dosed cefotaxime. METHODS: Adult critical care patients with indication for treatment with cefotaxime were randomized to treatment with either intermittent dosing (1 g every 6 h) or continuous dosing (4 g/24 h, after a loading dose of 1 g). We defined a preset target of reaching and maintaining a total cefotaxime concentration of 4 mg/L from 1 h after start of treatment. CCMO trial registration number NL50809.042.14, Clinicaltrials.gov NCT02560207. RESULTS: Twenty-nine and 30 patients, respectively, were included in the continuous dosing group and the intermittent dosing group. A total of 642 samples were available for analysis. In the continuous dosing arm, 89.3% met our preset target, compared with 50% in the intermittent dosing arm. Patients not reaching this target had a significantly higher creatinine clearance on the day of admission. CONCLUSIONS: These results support the application of a continuous dosing strategy of ß-lactams in critical care patients and the practice of therapeutic drug monitoring in a subset of patients with higher renal clearance and need for prolonged treatment for further optimization, where using total cefotaxime concentrations should suffice.

Bundled care in acute kidney injury in critically ill patients, a before-after educational intervention study.

BACKGROUND: Acute kidney injury (AKI) often occurs in critically ill patients. AKI is associated with mortality and morbidity. Interventions focusing on the reduction of AKI are suggested by the Kidney Disease: Improving Global Outcomes guideline. We hypothesized that these educational interventions would improve outcome in patients admitted to the Intensive Care Unit (ICU). METHODS: This was a pragmatic single-centre prospective observational before-after study design in an ICU in a tertiary referral hospital. All consecutive patients admitted to the ICU irrespective their illness were included. A 'Save the Kidney' (STK) bundle was encouraged via an educational intervention targeting health care providers. The educational STK bundle consisted of optimizing the fluid balance (based on urine output, serum lactate levels and/or central venous oxygen saturation), discontinuation of diuretics, maintaining a mean arterial pressure of at least 65 mmHg with the potential use of vasopressors and critical evaluation of the indication and dose of nephrotoxic drugs. The primary outcome was the composite of mortality, renal replacement therapy (RRT), and progression of AKI. Secondary outcomes were the components of the composite outcome the severity of AKI, ICU length of stay and in-hospital mortality. MAIN RESULTS: The primary outcome occurred in 451 patients (33%) in the STK group versus 375 patients (29%) in the usual care group, relative risk (RR) 1.16, 95% confidence interval (CI) 1.03-1.3, p < 0.001. Secondary outcomes were, ICU mortality in 6.8% versus 5.6%, (RR 1.22, 95% CI 0.90-1.64, p = 0.068), RRT in 1.6% versus 3.6% (RR 0.46, 95% CI 0.28-0.76, p = 0.002), and AKI progression in 28% versus 24% (RR 1.18, 95% CI 1.04-1.35, p = 0.001). CONCLUSIONS: Providing education to uniformly apply an AKI care bundle, without measurement of the implementation in a non-selected ICU population, targeted at prevention of AKI progression was not beneficial.

Renal Klotho is Reduced in Septic Patients and Pretreatment With Recombinant Klotho Attenuates Organ Injury in Lipopolysaccharide-Challenged Mice.

OBJECTIVES: To determine the applicability of recombinant Klotho to prevent inflammation and organ injury in sepsis in man and mice. DESIGN: Prospective, clinical laboratory study using "warm" human postmortem sepsis-acute kidney injury biopsies. Laboratory study using a mouse model of endotoxemia. SETTING: Research laboratory at a university teaching hospital. SUBJECTS: Adult patients who died of sepsis in the ICU and control patients undergoing total nephrectomy secondary to renal cancer; male C57BL/6 and Klotho haploinsufficient mice. INTERVENTIONS: Lipopolysaccharide (0.05 mg/kg) injection and kill after 4, 8, and 24 hours. Mice received recombinant Klotho (0.05 mg/kg) 30 minutes prior to lipopolysaccharide (1 mg/kg) injection. Mice treated with saline were included as controls. MEASUREMENTS AND MAIN RESULTS: Quantitative reverse transcription polymerase chain reaction and immunohistochemical staining were used to quantify Klotho messenger RNA and protein expression in the kidney of sepsis-acute kidney injury patients and the kidney and brain of mice. The messenger RNA and protein expression of damage markers, inflammatory cytokine, chemokines, and endothelial adhesion molecules were also determined in mice. Renal neutrophil influx was quantified. We found significantly lower renal Klotho messenger RNA and protein levels in sepsis-acute kidney injury biopsies than in control subjects. These findings were recapitulated in the kidney and brain of lipopolysaccharide-challenged mice. Decreased Klotho expression paralleled an increase in kidney damage markers neutrophil gelatinase-associated lipocalin and kidney injury molecule-1. Administration of recombinant Klotho prior to lipopolysaccharide injection attenuated organ damage, inflammation and endothelial activation in the kidney and brain of mice. Furthermore, less neutrophils infiltrated into the kidneys of recombinant Klotho mice compared with lipopolysaccharide only treated mice. CONCLUSIONS: Renal Klotho expression in human sepsis-acute kidney injury and in mouse models of sepsis was significantly decreased and correlated with renal damage. Recombinant Klotho intervention diminished organ damage, inflammation, and endothelial activation in the kidney and brain of lipopolysaccharide-challenged mice. Systemic Klotho replacement may potentially be an organ-protective therapy for septic patients to halt acute, inflammatory organ injury.

Molecular Regulation of Acute Tie2 Suppression in Sepsis.

OBJECTIVES: Tie2 is a tyrosine kinase receptor expressed by endothelial cells that maintains vascular barrier function. We recently reported that diverse critical illnesses acutely decrease Tie2 expression and that experimental Tie2 reduction suffices to recapitulate cardinal features of the septic vasculature. Here we investigated molecular mechanisms driving Tie2 suppression in settings of critical illness. DESIGN: Laboratory and animal research, postmortem kidney biopsies from acute kidney injury patients and serum from septic shock patients. SETTING: Research laboratories and ICU of Hannover Medical School, Harvard Medical School, and University of Groningen. PATIENTS: Deceased septic acute kidney injury patients (n = 16) and controls (n = 12) and septic shock patients (n = 57) and controls (n = 22). INTERVENTIONS: Molecular biology assays (Western blot, quantitative polymerase chain reaction) + in vitro models of flow and transendothelial electrical resistance experiments in human umbilical vein endothelial cells; murine cecal ligation and puncture and lipopolysaccharide administration. MEASUREMENTS AND MAIN RESULTS: We observed rapid reduction of both Tie2 messenger RNA and protein in mice following cecal ligation and puncture. In cultured endothelial cells exposed to tumor necrosis factor-α, suppression of Tie2 protein was more severe than Tie2 messenger RNA, suggesting distinct regulatory mechanisms. Evidence of protein-level regulation was found in tumor necrosis factor-α-treated endothelial cells, septic mice, and septic humans, all three of which displayed elevation of the soluble N-terminal fragment of Tie2. The matrix metalloprotease 14 was both necessary and sufficient for N-terminal Tie2 shedding. Since clinical settings of Tie2 suppression are often characterized by shock, we next investigated the effects of laminar flow on Tie2 expression. Compared with absence of flow, laminar flow induced both Tie2 messenger RNA and the expression of GATA binding protein 3. Conversely, septic lungs exhibited reduced GATA binding protein 3, and knockdown of GATA binding protein 3 in flow-exposed endothelial cells reduced Tie2 messenger RNA. Postmortem tissue from septic patients showed a trend toward reduced GATA binding protein 3 expression that was associated with Tie2 messenger RNA levels (p < 0.005). CONCLUSIONS: Tie2 suppression is a pivotal event in sepsis that may be regulated both by matrix metalloprotease 14-driven Tie2 protein cleavage and GATA binding protein 3-driven flow regulation of Tie2 transcript.

Intracellular RIG-I Signaling Regulates TLR4-Independent Endothelial Inflammatory Responses to Endotoxin.

Sepsis is a systemic inflammatory response to infections associated with organ failure that is the most frequent cause of death in hospitalized patients. Exaggerated endothelial activation, altered blood flow, vascular leakage, and other disturbances synergistically contribute to sepsis-induced organ failure. The underlying signaling events associated with endothelial proinflammatory activation are not well understood, yet they likely consist of molecular pathways that act in an endothelium-specific manner. We found that LPS, a critical factor in the pathogenesis of sepsis, is internalized by endothelial cells, leading to intracellular signaling without the need for priming as found recently in immune cells. By identifying a novel role for retinoic acid-inducible gene-I (RIG-I) as a central regulator of endothelial activation functioning independent of TLR4, we provide evidence that the current paradigm of TLR4 solely being responsible for LPS-mediated endothelial responses is incomplete. RIG-I, as well as the adaptor protein mitochondrial antiviral signaling protein, regulates NF-κB-mediated induction of adhesion molecules and proinflammatory cytokine expression in response to LPS. Our findings provide essential new insights into the proinflammatory signaling pathways in endothelial cells and suggest that combined endothelial-specific inhibition of RIG-I and TLR4 will provide protection from aberrant endothelial responses associated with sepsis.

Kidney histopathology in lethal human sepsis.

PURPOSE: The histopathology of sepsis-associated acute kidney injury (AKI) in critically ill patients remains an understudied area. Previous studies have identified that acute tubular necrosis (ATN) is not the only driver of sepsis-AKI. The focus of this study was to identify additional candidate processes that may drive sepsis-AKI. To do this we immunohistochemically characterized the histopathological and cellular features in various compartments of human septic kidneys. METHODS: We studied the following histopathological features: leukocyte subsets, fibroblast activation, cellular proliferation, apoptosis, and fibrin deposition in the glomerulus and the tubulointerstitium in human post-mortem kidney biopsy tissue. Biopsy tissue samples from 27 patients with sepsis-AKI were collected 33 min (range 24-150) after death in the ICU. The unaffected part of the kidneys from 12 patients undergoing total nephrectomy as a result of renal carcinoma served as controls. RESULTS: Immunohistochemical analysis revealed the presence of more neutrophils and macrophages in the glomeruli and more neutrophils in the tubulointerstitium of renal tissue from patients with sepsis compared to control renal tissue. Type II macrophages were predominant, with some macrophages expressing both type I and type II markers. In contrast, there were almost no macrophages found in control kidneys. The number of activated (myo)fibroblasts was low in the glomeruli of sepsis-AKI kidneys, yet this was not observed in the tubulointerstitium. Cell proliferation and fibrin deposition were more pronounced in the glomeruli and tubulointerstitium of sepsis-AKI than in control kidneys. CONCLUSIONS: The extensive heterogeneity of observations among and within patients emphasizes the need to thoroughly characterize patients with sepsis-AKI in a large sample of renal biopsy tissue from patients with sepsis.

Low Caspofungin Exposure in Patients in Intensive Care Units.

In critically ill patients, drug exposure may be influenced by altered drug distribution and clearance. Earlier studies showed that the variability in caspofungin exposure was high in intensive care unit (ICU) patients. The primary objective of this study was to determine if the standard dose of caspofungin resulted in adequate exposure in critically ill patients. A multicenter prospective study in ICU patients with (suspected) invasive candidiasis was conducted in the Netherlands from November 2013 to October 2015. Patients received standard caspofungin treatment, and the exposure was determined on day 3 of treatment. An area under the concentration-time curve from 0 to 24 h (AUC0-24) of 98 mg · h/liter was considered adequate exposure. In case of low exposure (i.e., <79 mg · h/liter, a ≥20% lower AUC0-24), the caspofungin dose was increased and the exposure reevaluated. Twenty patients were included in the study, of whom 5 had a positive blood culture. The median caspofungin AUC0-24 at day 3 was 78 mg · h/liter (interquartile range [IQR], 69 to 97 mg · h/liter). A low AUC0-24 (<79 mg · h/liter) was seen in 10 patients. The AUC0-24 was significantly and positively correlated with the caspofungin dose in mg/kg/day (P = 0.011). The median AUC0-24 with a caspofungin dose of 1 mg/kg was estimated using a pharmacokinetic model and was 114.9 mg · h/liter (IQR, 103.2 to 143.5 mg · h/liter). In conclusion, the caspofungin exposure in ICU patients in this study was low compared with that in healthy volunteers and other (non)critically ill patients, most likely due to a larger volume of distribution. A weight-based dose regimen is probably more suitable for patients with substantially altered drug distribution. (This study has been registered at ClinicalTrials.gov under registration no. NCT01994096.).

Voriconazole metabolism is influenced by severe inflammation: a prospective study.

BACKGROUND: During an infection or inflammation, several drug-metabolizing enzymes in the liver are down-regulated, including cytochrome P450 iso-enzymes. Since voriconazole is extensively metabolized by cytochrome P450 iso-enzymes, the metabolism of voriconazole can be influenced during inflammation via reduced clearance of the drug, resulting in higher voriconazole trough concentrations. OBJECTIVE: To investigate prospectively the influence of inflammation on voriconazole metabolism and voriconazole trough concentrations. METHODS: A prospective observational study was performed at the University Medical Center Groningen. Patients were eligible for inclusion if they were ≥18 years old and treated with voriconazole. Voriconazole and voriconazole-N-oxide concentrations were determined in discarded blood samples. To determine the degree of inflammation, C-reactive protein (CRP) concentrations were used. Subsequently, a longitudinal data analysis was performed to assess the effect of inflammation on the metabolic ratio and voriconazole trough concentration. RESULTS: Thirty-four patients were included. In total 489 voriconazole trough concentrations were included in the longitudinal data analysis. This analysis showed that inflammation, reflected by CRP concentrations, significantly influenced the metabolic ratio, voriconazole trough concentration and voriconazole-N-oxide concentration (all P < 0.001), when corrected for other factors that could influence voriconazole metabolism. The metabolic ratio was decreased by 0.99229N and the voriconazole-N-oxide concentration by 0.99775N, while the voriconazole trough concentration was increased by 1.005321N, where N is the difference in CRP units (in mg/L). CONCLUSIONS: This study shows that voriconazole metabolism is decreased during inflammation, resulting in higher voriconazole trough concentrations. Therefore, frequent monitoring of voriconazole serum concentrations is recommended during and following severe inflammation.

Satisfaction with quality of ICU care for patients and families: the euroQ2 project.

BACKGROUND: Families' perspectives are of great importance in evaluating quality of care in the intensive care unit (ICU). This Danish-Dutch study tested a European adaptation of the "Family Satisfaction in the ICU" (euroFS-ICU). The aim of the study was to examine assessments of satisfaction with care in a large cohort of Danish and Dutch family members and to examine the measurement characteristics of the euroFS-ICU. METHODS: Data were from 11 Danish and 10 Dutch ICUs and included family members of patients admitted to the ICU for 48 hours or more. Surveys were mailed 3 weeks after patient discharge from the ICU. Selected patient characteristics were retrieved from hospital records. RESULTS: A total of 1077 family members of 920 ICU patients participated. The response rate among family members who were approached was 72%. "Excellent" or "Very good" ratings on all items ranged from 58% to 96%. Items with the highest ratings were concern toward patients, ICU atmosphere, opportunities to be present at the bedside, and ease of getting information. Items with room for improvement were management of patient agitation, emotional support of the family, consistency of information, and inclusion in and support during decision-making processes. Exploratory factor analysis suggested four underlying factors, but confirmatory factor analysis failed to yield a multi-factor model with between-country measurement invariance. A hypothesis that this failure was due to misspecification of causal indicators as reflective indicators was supported by analysis of a factor representing satisfaction with communication, measured with a combination of causal and reflective indicators. CONCLUSIONS: Most family members were moderately or very satisfied with patient care, family care, information and decision-making, but areas with room for improvement were also identified. Psychometric assessments suggest that composite scores constructed from these items as representations of either overall satisfaction or satisfaction with specific sub-domains do not meet rigorous measurement standards. The euroFS-ICU and other similar instruments may benefit from adding reflective indicators.

Voriconazole Therapeutic Drug Monitoring Practices in Intensive Care.

BACKGROUND: Routine therapeutic drug monitoring of voriconazole seems to be beneficial. This study investigated the therapeutic drug monitoring practices in intensive care to derive possible recommendations for improvement. METHODS: A retrospective chart review was performed for patients aged ≥18 years who started treatment with voriconazole, which lasted for at least 3 days while being admitted to an intensive care unit to assess possible differences between the patients with and without voriconazole trough concentrations measured. RESULTS: In 64 (76%) of the 84 patients, voriconazole trough concentrations were measured. The groups differed significantly with respect to the duration of voriconazole treatment and intensive care unit admission. Time of sampling was very early and therefore inappropriate for 49% of the first measured voriconazole trough concentrations and in 48% of the subsequent measured concentrations. Of the 349 trough concentrations measured, 129 (37%) were outside the therapeutic window. In 11% of these cases, no recommendation was provided without identifiable reason. In addition, 27% of recommended dose adjustments were not implemented, probably because the advice was not suited for the specific clinical situation. CONCLUSIONS: The performance of voriconazole therapeutic drug monitoring can still be improved although voriconazole concentrations were monitored in most patients. A multidisciplinary approach-for instance by means of antifungal stewardship-will probably be able to overcome problems encountered such as timing of sampling, incompleteness of data in clinical context, and lack of implementation of recommendations.

Emerging pan-resistance in Trichosporon species: a case report.

BACKGROUND: Trichosporon species are ubiquitously spread and known to be part of the normal human flora of the skin and gastrointestinal tract. Trichosporon spp. normally cause superficial infections. However, in the past decade Trichosporon spp. are emerging as opportunistic agents of invasive fungal infections, particularly in severely immunocompromised patients. Clinical isolates are usually sensitive to triazoles, but strains resistant to multiple triazoles have been reported. CASE PRESENTATION: We report a high-level pan-azole resistant Trichosporon dermatis isolate causing an invasive cholangitis in a patient after liver re-transplantation. This infection occurred despite of fluconazole and low dose amphotericin B prophylaxis, and treatment with combined liposomal amphotericin B and voriconazole failed. CONCLUSION: This case and recent reports in literature show that not only bacteria are evolving towards pan-resistance, but also pathogenic yeasts. Prudent use of antifungals is important to withstand emerging antifungal resistance.

Limited-sampling strategies for anidulafungin in critically ill patients.

Efficacy of anidulafungin is driven by the area under the concentration-time curve (AUC)/MIC ratio. Determination of the anidulafungin AUC along with MIC values can therefore be useful. Since obtaining a full concentration-time curve to determine an AUC is not always feasible or appropriate, limited-sampling strategies may be useful in adequately estimating exposure. The objective of this study was to develop a model to predict the individual anidulafungin exposure in critically ill patients using limited-sampling strategies. Pharmacokinetic data were derived from 20 critically ill patients with invasive candidiasis treated with anidulafungin. These data were used to develop a two-compartment model in MW\Pharm using an iterative 2-stage Bayesian procedure. Limited-sampling strategies were subsequently investigated using two methods, a Bayesian analysis and a linear regression analysis. The best possible strategies for these two methods were evaluated by a Bland-Altman analysis for correlation of the predicted and observed AUC from 0 to 24 h (AUC0-24) values. Anidulafungin exposure can be adequately estimated with the concentration from a single sample drawn 12 h after the start of the infusion either by linear regression (R2=0.99; bias, 0.05%; root mean square error [RMSE], 3%) or using a population pharmacokinetic model (R2=0.89; bias, -0.1%; RMSE, 9%) in critically ill patients and also in less severely ill patients, as reflected by healthy volunteers. Limited sampling can be advantageous for future studies evaluating the pharmacokinetics and pharmacodynamics of anidulafungin and for therapeutic drug monitoring in selected patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01047267.).