AUCs and 123s: a critical appraisal of vancomycin therapeutic drug monitoring in paediatrics.

The revised vancomycin guidelines recommend implementing AUC24-based therapeutic drug monitoring (TDM) using Bayesian methods in both adults and paediatrics. The motivation for this change was accumulating evidence showing aggressive dosing to achieve high troughs, as recommended in the first guidelines for adults and extrapolated to paediatrics, is associated with increased nephrotoxicity without improving clinical outcomes. AUC24-based TDM requires substantial resources that may need to be diverted from other valuable interventions. It can therefore be justified only after certain assumptions are shown to be true: (i) there is a clear relationship between vancomycin efficacy and/or toxicity and the proposed therapeutic range; and (ii) maintaining exposure within the target range with AUC24-based TDM improves clinical outcomes and/or decreases toxicity. In this review, we critically appraise the scientific basis for these assumptions. We find studies evaluating the relationship between vancomycin AUC24/MIC and efficacy in adults and children do not offer strong support for the recommended lower limit of the proposed therapeutic range (i.e. AUC24/MIC ≥400). Nephrotoxicity in children increases in a stepwise manner along the vancomycin exposure continuum but it is unclear if one parameter (AUC24 versus trough) is a superior predictor. Overall, evidence in children suggests good-to-excellent correlation between AUC24 and trough. Most importantly, there is no convincing evidence that the method of vancomycin TDM has a causal role in improving efficacy or reducing toxicity. These findings question the need to transition to resource-intensive AUC24-based TDM over retaining trough-based TDM with lower targets to minimize nephrotoxicity in paediatrics.

Long-Term Effects of Phased Implementation of Antimicrobial Stewardship in Academic ICUs: 2007-2015.

OBJECTIVES: Antimicrobial stewardship is advocated to reduce antimicrobial resistance in ICUs by reducing unnecessary antimicrobial consumption. Evidence has been limited to short, single-center studies. We evaluated whether antimicrobial stewardship in ICUs could reduce antimicrobial consumption and costs. DESIGN: We conducted a phased, multisite cohort study of a quality improvement initiative. SETTING: Antimicrobial stewardship was implemented in four academic ICUs in Toronto, Canada beginning in February 2009 and ending in July 2012. PATIENTS: All patients admitted to each ICU from January 1, 2007, to December 31, 2015, were included. INTERVENTIONS: Antimicrobial stewardship was delivered using in-person coaching by pharmacists and physicians three to five times weekly, and supplemented with unit-based performance reports. Total monthly antimicrobial consumption (measured by defined daily doses/100 patient-days) and costs (Canadian dollars/100 patient-days) before and after antimicrobial stewardship implementation were measured. MEASUREMENTS AND MAIN RESULTS: A total of 239,123 patient-days (57,195 patients) were analyzed, with 148,832 patient-days following introduction of antimicrobial stewardship. Antibacterial use decreased from 120.90 to 110.50 defined daily dose/100 patient-days following introduction of antimicrobial stewardship (adjusted intervention effect -12.12 defined daily dose/100 patient-days; 95% CI, -16.75 to -7.49; p < 0.001) and total antifungal use decreased from 30.53 to 27.37 defined daily doses/100 patient-days (adjusted intervention effect -3.16 defined daily dose/100 patient-days; 95% CI, -8.33 to 0.04; p = 0.05). Monthly antimicrobial costs decreased from $3195.56 to $1998.59 (adjusted intervention effect -$642.35; 95% CI, -$905.85 to -$378.84; p < 0.001) and total antifungal costs were unchanged from $1771.86 to $2027.54 (adjusted intervention effect -$355.27; 95% CI, -$837.88 to $127.33; p = 0.15). Mortality remained unchanged, with no consistent effects on antimicrobial resistance and candidemia. CONCLUSIONS: Antimicrobial stewardship in ICUs with coaching plus audit and feedback is associated with sustained improvements in antimicrobial consumption and cost. ICUs with high antimicrobial consumption or expenditure should consider implementing antimicrobial stewardship programs.

Use of a structured panel process to define antimicrobial prescribing appropriateness in critical care.

BACKGROUND: Antimicrobial prescribing is frequently reported as appropriate or inappropriate, particularly in the ICU. However, the definitions used are non-standardized and lack validity and reliability. OBJECTIVES: To develop standardized definitions of appropriateness for antimicrobial prescribing in the critical care setting. METHODS: We used consensus-based modified Delphi and RAND appropriateness methodology to develop criteria to define appropriateness of antimicrobial prescribing. A multiphased approach with an online questionnaire followed by a facilitated in-person meeting was utilized and included clinicians from a variety of practice areas (e.g. surgeons, infectious diseases specialists, intensivists, transplant specialists and pharmacists). RESULTS: There were a total of 23 criteria agreed upon to define the following categories of antimicrobial prescribing: appropriate; effective but unnecessary; inappropriate; and under-treatment. CONCLUSIONS: These standardized criteria for appropriateness may be generalizable to other patient populations and utilized with other tools to adjudicate prescribing practices.

A National Survey of Critical Care Physicians' Knowledge, Attitudes, and Perceptions of Antimicrobial Stewardship Programs.

OBJECTIVE: Antimicrobial stewardship is a process designed to optimize antimicrobial therapy by ensuring patients get the right antimicrobials at the right dose and at the right time. Antimicrobial stewardship programs (ASPs) are increasingly being implemented in health care institutions, are required by some accreditation bodies, and have the potential for maximum impact in intensive care units (ICUs). We administered a survey to critical care physicians across Canada to better understand their knowledge, attitudes, and perceptions on the utility of ASPs in improving patient care. DESIGN, SETTING, AND PATIENTS: We distributed a Web-based survey to physicians who attend in Canadian ICUs. Respondents were identified through the membership lists of multiple critical care organizations. Content validity, utility, clarity, and test-retest reliability were evaluated prior to distribution. Survey items assessed ASP knowledge, attitudes, and experiences. Attitudes toward ASPs were assessed on a 5-point Likert-type scale. MEASUREMENTS AND MAIN RESULTS: The survey was completed by 185 physicians, with a response rate of 29% (n = 185/634) for all physicians contacted. A majority (74%) of respondents reported that there was at least 1 component of an ASP at their institution. Most (86%) respondents agreed or strongly agreed that the patients in their ICU benefit from an ASP, with 81% reporting the ASP increases their knowledge of appropriate antimicrobial use in the ICU setting. Only 11% of respondents reported they felt that time spent interacting with the ASP team was an inefficient use of their time, and only 7% expressed concern that the ASP negatively affected their autonomy. CONCLUSION: Based on our survey results, Canadian intensivists are supportive of antimicrobial stewardship in ICUs and feel that ASPs provide a valuable service to both patients and clinicians.

A national survey of antimicrobial stewardship content in Canadian entry-to-practice pharmacy programs.

Objective: To describe the current landscape of antimicrobial stewardship (AMS) instruction in Canadian entry-to-practice pharmacy programs and the perceived barriers and facilitators to optimizing teaching and learning. Design: Electronic survey. Participants: Faculty representatives from the 10 Canadian entry-to-practice pharmacy programs, including content experts and faculty leadership. Methods: A review of international literature pertaining to AMS in pharmacy curricula informed a 24-item survey, which was open for completion from March to May of 2021. Curriculum content questions were developed using AMS topics recommended by pharmacy educators in the United States, and professional roles described by the Association of Faculties of Pharmacy of Canada. Results: All 10 Canadian faculties returned a completed survey. All programs reported teaching AMS principles in their core curricula. Content coverage varied, with programs teaching, on average, 68% of the recommended AMS topics from the United States. Potential gaps were identified within the professional roles of "communicator" and "collaborator." Didactic methods of content delivery and student assessment, such as lectures and multiple-choice questions, were most frequently used. Three programs offered additional AMS content in their elective curricula. Experiential rotations in AMS were commonly offered, though teaching AMS in formalized interprofessional settings was rare. Curricular time constraints were identified by all programs as a barrier to enhancing AMS instruction. A course to teach AMS, a curriculum framework, and prioritization by the faculty's curriculum committee were perceived as facilitators. Conclusions: Our findings highlight potential gaps and areas of opportunity within Canadian pharmacy AMS instruction.

Impact of accessory gene regulator (agr) dysfunction on vancomycin pharmacodynamics among Canadian community and health-care associated methicillin-resistant Staphylococcus aureus.

BACKGROUND: The accessory gene regulator (agr) is a quorum sensing cluster of genes which control colonization and virulence in Staphylococcus aureus. We evaluated agr function in community- (CA) and healthcare-associated (HA) MRSA, to compare the pharmacodynamics and bactericidal activity of vancomycin against agr functional and dysfunctional HA-MRSA and CA-MRSA. METHODS: 40 clinical isolates of MRSA from the Canadian Nosocomial Infection Surveillance Program were evaluated for delta-haemolysin production, as a surrogate marker of agr function. Time kill experiments were performed for vancomycin at 0 to 64 times the MIC against an initial inoculum of 10(6) and 10(8) cfu/ml of agr functional and dysfunctional CA-MRSA and HA-MRSA and these data were fit to a hill-type pharmacodynamic model. RESULTS: 15% isolates were agr dysfunctional, which was higher among HA-MRSA (26.3%) versus CA-MRSA (4.76%). Against a low initial inoculum of 10(6) cfu/ml of CA-MRSA, vancomycin pharmacodynamics were similar among agr functional and dysfunctional strains. However, against a high initial inoculum of 10(8) cfu/ml, killing activity was notably attenuated against agr dysfunctional CA-MRSA (USA400) and HA-MRSA (USA100). CA-MRSA displayed a 20.0 fold decrease in the maximal reduction in bacterial counts (Emax) which was 3.71 log(10) CFU/ml for agr functional vs. 2.41 log(10) CFU/ml for agr dysfunctional MRSA (p = 0.0007). CONCLUSIONS: Dysfunction in agr was less common among CA-MRSA vs. HA-MRSA. agr dysfunction demonstrated an impact on vancomycin bactericidal activity and pharmacodynamics against a high initial inoculum of CA-MRSA and HA-MRSA, which may have implications for optimal antimicrobial therapy against persistent, difficult to treat MRSA infections.

Remdesivir: Review of Pharmacology, Pre-clinical Data, and Emerging Clinical Experience for COVID-19.

The global pandemic of novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created an urgent need for effective antivirals. Remdesivir (formerly GS-5734) is a nucleoside analogue pro-drug currently being evaluated in COVID-19 clinical trials. Its unique structural features allow high concentrations of the active triphosphate metabolite to be delivered intracellularly and it evades proofreading to successfully inhibit viral RNA synthesis. In pre-clinical models, remdesivir has demonstrated potent antiviral activity against diverse human and zoonotic ß-coronaviruses, including SARS-CoV-2. In this article, we critically review available data on remdesivir with an emphasis on biochemistry, pharmacology, pharmacokinetics, and in vitro activity against coronaviruses as well as clinical experience and current progress in COVID-19 clinical trials.

Baricitinib: A Review of Pharmacology, Safety, and Emerging Clinical Experience in COVID-19.

A hyperinflammatory response to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection, reminiscent of cytokine release syndrome, has been implicated in the pathophysiology of acute respiratory distress syndrome and organ damage in patients with coronavirus disease 2019 (COVID-19). Agents that inhibit components of the pro-inflammatory cascade have garnered interest as potential treatment options with hopes that dampening the proinflammatory process may improve clinical outcomes. Baricitinib is a reversible Janus-associated kinase (JAK)-inhibitor that interrupts the signaling of multiple cytokines implicated in COVID-19 immunopathology. It may also have antiviral effects by targeting host factors that viruses rely for cell entry and by suppressing type I interferon driven angiotensin-converting-enzyme-2 upregulation. However, baricitinib's immunosuppressive effects may be detrimental during acute viral infections by delaying viral clearance and increasing vulnerability to secondary opportunistic infections. The lack of reliable biomarkers to monitor patients' immune status as illness evolves complicates deployment of immunosuppressive drugs like baricitinib. Furthermore, baricitinib carries the risk of increased thromboembolic events, which is concerning given the proclivity towards a hypercoagulable state in patients with COVID-19. In this article, we review available data on baricitinib with an emphasis on immunosuppressive and antiviral pharmacology, pharmacokinetics, safety, and current progress in COVID-19 clinical trials.