Simulation to optimize the laboratory diagnosis of bacteremia.

Blood cultures are central to the management of patients with sepsis and bloodstream infection. Clinical decisions depend on the timely availability of laboratory information, which, in turn, depends on the optimal laboratory processing of specimens. Discrete event simulation (DES) offers insights into where optimization efforts can be targeted. Here, we generate a detailed process map of blood culture processing within a laboratory and use it to build a simulator. Direct observation of laboratory staff processing blood cultures was used to generate a flowchart of the blood culture laboratory pathway. Retrospective routinely collected data were combined with direct observations to generate probability distributions over the time taken for each event. These data were used to inform the DES model. A sensitivity analysis explored the impact of staff availability on turnaround times. A flowchart of the blood culture pathway was constructed, spanning labeling, incubation, organism identification, and antimicrobial susceptibility testing. Thirteen processes in earlier stages of the pathway, not otherwise captured by routinely collected data, were timed using direct observations. Observations revealed that specimen processing is predominantly batched. Another eight processes were timed using retrospective data. A simulator was built using DES. Sensitivity analysis revealed that specimen progression through the simulation was especially sensitive to laboratory technician availability. Gram stain reporting time was also sensitive to laboratory scientist availability. Our laboratory simulation model has wide-ranging applications for the optimization of laboratory processes and effective implementation of the changes required for faster and more accurate results. IMPORTANCE: Optimization of laboratory pathways and resource availability has a direct impact on the clinical management of patients with bloodstream infection. This research offers an insight into the laboratory processing of blood cultures at a system level and allows clinical microbiology laboratories to explore the impact of changes to processes and resources.

Bayesian Calibration to Address the Challenge of Antimicrobial Resistance: A Review.

Antimicrobial resistance (AMR) emerges when disease-causing microorganisms develop the ability to withstand the effects of antimicrobial therapy. This phenomenon is often fueled by the human-to-human transmission of pathogens and the overuse of antibiotics. Over the past 50 years, increased computational power has facilitated the application of Bayesian inference algorithms. In this comprehensive review, the basic theory of Markov Chain Monte Carlo (MCMC) and Sequential Monte Carlo (SMC) methods are explained. These inference algorithms are instrumental in calibrating complex statistical models to the vast amounts of AMR-related data. Popular statistical models include hierarchical and mixture models as well as discrete and stochastic epidemiological compartmental and agent based models. Studies encompassed multi-drug resistance, economic implications of vaccines, and modeling AMR in vitro as well as within specific populations. We describe how combining these topics in a coherent framework can result in an effective antimicrobial stewardship. We also outline recent advancements in the methodology of Bayesian inference algorithms and provide insights into their prospective applicability for modeling AMR in the future.

Avoid the Peel: Citrus Fruit Bezoar Causing Intestinal Perforation.

We report a highly unusual case of small bowel obstruction in an 86-year-old man from ingestion of a citrus fruit, known as kumquats, which led to intestinal perforation and peritonitis. He initially presented with a one-day history of diffuse abdominal pain associated with nausea and feculent emesis after eating whole pieces of unpeeled kumquats. When symptoms of peritonitis evolved with a blood lactate of 5.1 mg/dL, he was urgently taken to the operating room for exploration. Multiple areas with fibrous exudates and full-thickness ulceration were encountered along the distal jejunum and proximal ileum, with a partially obstructing intraluminal mass in the distal ileum. Treatment involved resection of 70 cm of non-viable bowel, removal of the intraluminal mass, and surgical re-establishment of intestinal continuity. Unpeeled kumquats were confirmed to have caused these intestinal findings. The patient did well following the operation and has had no further problems referred to by this management.

Integration of genomic and pharmacokinetic data to predict clinical outcomes in HIV-associated cryptococcal meningitis.

Cryptococcal meningitis causes an estimated 112,000 global deaths per annum. Genomic and phenotypic features of the infecting strain of Cryptococcus spp. have been associated with outcomes from cryptococcal meningitis. Additionally, population-level pharmacokinetic variability is well documented in these patient cohorts. The relative contribution of these factors to clinical outcomes is unknown. Based in Malawi, we conducted a sub-study of the phase 3 Ambition-CM trial (ISRCTN72509687), collecting plasma and cerebrospinal fluid at serial time points during the first 14 days of antifungal therapy. We explored the relative contribution of pathogen genotype, drug resistance phenotype, and pharmacokinetics on clinical outcomes including lumbar opening pressure, pharmacodynamic effect, and mortality. We report remarkable genomic homogeneity among infecting strains of Cryptococcus spp., within and between patients. There was no evidence of acquisition of antifungal resistance in our isolates. Genotypic features of the infecting strain were not consistently associated with adverse or favorable clinical outcomes. However, baseline fungal burden and early fungicidal activity (EFA) were associated with mortality. The strongest predictor of EFA was the level of exposure to amphotericin B. Our analysis suggests the most effective means of improving clinical outcomes from HIV-associated cryptococcal meningitis is to optimize exposure to potent antifungal therapy. IMPORTANCE: HIV-associated cryptococcal meningitis is associated with a high burden of mortality. Research into the different strain types causing this disease has yielded inconsistent findings in terms of which strains are associated with worse clinical outcomes. Our study suggests that the exposure of patients to potent anti-cryptococcal drugs has a more significant impact on clinical outcomes than the strain type of the infecting organism. Future research should focus on optimizing drug exposure, particularly in the context of novel anticryptococcal drugs coming into clinical use.

Acinetobacter baumannii transformants expressing oxacillinases and metallo-ß-lactamases that confer resistance to meropenem: new tools for anti-Acinetobacter drug development and AMR preparedness.

Antimicrobial resistance (AMR) in Acinetobacter baumannii is an unmet medical need. Multiple drug-resistant/extremely drug-resistant strains of A. baumannii do not display growth well in in vivo models, and consequently, their response to antibacterial therapy is inconsistent. We addressed this issue by engineering carbapenem resistance motifs into the highly virulent genetic background of A. baumannii AB5075. This strain has a chromosomally encoded oxa-23 that was deleted (Δoxa-23), then plasmids expressing oxa-23, oxa-24/40, oxa-58, imp-1, vim-2, and ndm-1 were introduced to create the mutant strains. Each transformant was used as a challenge strain in a neutropenic murine thigh infection model and assessed for the extent of growth and response to meropenem 200 mg/kg subcutaneously every 6 h (q6h). Pharmacodynamic analyses were performed by transforming drug exposure from dose (mg/kg) to the fraction of the dosing interval; free meropenem concentrations were >minimum inhibitory concentration (MIC) (fT > MIC). AB5075 and the AB5075Δoxa-23 mutant had a MICs of 32 and 4 mg/L, respectively. The transformants harboring oxacillinases oxa-24/40 and oxa-58 had an MIC of 64 mg/L. The metallo-ß-lactamases imp-1, vim-2, and ndm-1 had MICs of 128, 64, and 64 mg/L, respectively. All vehicle-treated transformants displayed in vivo growth in the range of 0.75-1.4 log. The response to meropenem was consistent with the varying fT > MIC of the transformants and was readily described by an inhibitory sigmoid Emax relationship. Stasis was achieved with a fT > MIC of 0.36. These A. baumannii transformants are invaluable new tools for the assessment of anti-Acinetobacter compounds and provide a new pathway for AMR preparedness.

Research prioritization in hernia surgery: a modified Delphi ACHQC and VHOC expert consensus.

PURPOSE: Numerous clinical practice guidelines and consensus statements have been published in hernia surgery, however, there is still a need for high-quality evidence to address remaining unanswered questions. The aim of this study was to conduct research priority setting through a modified Delphi process to identify a list of top research priorities in hernia surgery. METHODS: A structured literature review of clinical practice guidelines was performed by the steering committee. Topics considered clinically significant, practical to study and lacking strong evidence were extracted and refined into a comprehensive list, then entered into a two-round Delphi survey for prioritization at the Abdominal Core Health Quality Collaborative (ACHQC) Quality Improvement Summit. In round 1, participants were instructed to select any topic that should be prioritized for future research. Topics were ranked according to the proportion of votes and the 25 highest-ranking topics were included in the second round. In round 2, participants were instructed to select only the top 10 topics for research prioritization. RESULTS: Eleven clinical practice guidelines were reviewed. Eighty-seven topics were extracted by the steering committee and submitted for prioritization. After the first round, 25 of the highest-ranking topics were determined and included in the second round. A final list of 11 research questions was identified. The hernia types with the most research interest were inguinal and epigastric/umbilical hernias. Other topics of high interest were the management of diastasis recti, primary versus mesh repairs and expectant management versus surgical repair. CONCLUSION: Our study provides a research agenda generated through expert consensus that may be used in the prioritization of the design and funding of clinical trials in hernia surgery.

Retrorectus Ventral Hernia Repair Utilizing T-line Hernia Mesh: Technical Descriptions.

The T-line hernia mesh is a synthetic, polypropylene mesh with mesh suture extensions designed to prevent anchor point failure by evenly distributing tension across the soft tissue. Previous studies have demonstrated the success of onlay ventral hernia repair with T-line hernia mesh, but retrorectus applications of the mesh have not yet been characterized. This technique article illustrates technical descriptions and clinical applications of the T-line hernia mesh in the retrorectus plane.

Bayesian estimation of the prevalence of antimicrobial resistance: a mathematical modelling study.

BACKGROUND: Estimates of the prevalence of antimicrobial resistance (AMR) underpin effective antimicrobial stewardship, infection prevention and control, and optimal deployment of antimicrobial agents. Typically, the prevalence of AMR is determined from real-world antimicrobial susceptibility data that are time delimited, sparse, and often biased, potentially resulting in harmful and wasteful decision-making. Frequentist methods are resource intensive because they rely on large datasets. OBJECTIVES: To determine whether a Bayesian approach could present a more reliable and more resource-efficient way to estimate population prevalence of AMR than traditional frequentist methods. METHODS: Retrospectively collected, open-source, real-world pseudonymized healthcare data were used to develop a Bayesian approach for estimating the prevalence of AMR by combination with prior AMR information from a contextualized review of literature. Iterative random sampling and cross-validation were used to assess the predictive accuracy and potential resource efficiency of the Bayesian approach compared with a standard frequentist approach. RESULTS: Bayesian estimation of AMR prevalence made fewer extreme estimation errors than a frequentist estimation approach [n = 74 (6.4%) versus n = 136 (11.8%)] and required fewer observed antimicrobial susceptibility results per pathogen on average [mean = 28.8 (SD = 22.1) versus mean = 34.4 (SD = 30.1)] to avoid any extreme estimation errors in 50 iterations of the cross-validation. The Bayesian approach was maximally effective and efficient for drug-pathogen combinations where the actual prevalence of resistance was not close to 0% or 100%. CONCLUSIONS: Bayesian estimation of the prevalence of AMR could provide a simple, resource-efficient approach to better inform population infection management where uncertainty about AMR prevalence is high.

Towards pharmacokinetic boosting of phenoxymethylpenicillin (penicillin-V) using probenecid for the treatment of bacterial infections.

In the face of increasing antimicrobial tolerance and resistance there is a global obligation to optimise oral antimicrobial dosing strategies including narrow spectrum penicillins, such as penicillin-V. We conducted a randomised, crossover study in healthy volunteers to characterise the influence of probenecid on penicillin-V pharmacokinetics and estimate the pharmacodynamics against Streptococcus pneumoniae. Twenty participants took six doses of penicillin-V (250 mg, 500 mg or 750 mg four times daily) with and without probenecid. Total and free concentrations of penicillin-V and probenecid were measured at two timepoints. A pharmacokinetic model was developed, and the probability of target attainment (PTA) calculated. The mean difference (95% CI) between penicillin-V alone and in combination with probenecid for serum total and free penicillin-V concentrations was significantly different at both timepoints (total: 45 min 4.32 (3.20-5.32) mg/L p < 0.001, 180 min 2.2 (1.58-3.25) mg/L p < 0.001; free: 45 min 1.15 (0.88-1.42) mg/L p < 0.001, 180 min 0.5 (0.35-0.76) mg/L p < 0.001). There was no difference between the timepoints in probenecid concentrations. PTA analysis shows probenecid allows a fourfold increase in MIC cover. Addition of probenecid was safe and well tolerated. The data support further research into improved dosing structures for complex outpatient therapy and might also be used to address penicillin supply shortages.

The pathobiology of human fungal infections.

Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.

Biomarker Driven Antifungal Stewardship (BioDriveAFS) in acute leukaemia-a multi-centre randomised controlled trial to assess clinical and cost effectiveness: a study protocol for a randomised controlled trial.

BACKGROUND: Acute leukaemias (AL) are life-threatening blood cancers that can be potentially cured with treatment involving myelosuppressive, multiagent, intensive chemotherapy (IC). However, such treatment is associated with a risk of serious infection, in particular invasive fungal infection (IFI) associated with prolonged neutropenia. Current practice guidelines recommend primary antifungal (AF) prophylaxis to be administered to high-risk patients to reduce IFI incidence. AFs are also used empirically to manage prolonged neutropenic fever. Current strategies lead to substantial overuse of AFs. Galactomannan (GM) and ß-D-glucan (BG) biomarkers are also used to diagnose IFI. Combining both biomarkers may enhance the predictability of IFI compared to administering each test alone. Currently, no large-scale randomised controlled trial (RCT) has directly compared a biomarker-based diagnostic screening strategy without AF prophylaxis to AF prophylaxis (without systematic biomarker testing). METHODS: BioDriveAFS is a multicentre, parallel, two-arm RCT of 404 participants from UK NHS Haematology departments. Participants will be allocated on a 1:1 basis to receive either a biomarker-based antifungal stewardship (AFS) strategy, or a prophylactic AF strategy, which includes existing standard of care (SoC). The co-primary outcomes will be AF exposure in the 12-month post randomisation and the patient-reported EQ-5D-5L measured at 12-month post randomisation. Secondary outcomes will include total AF exposure, probable/proven IFI, survival (all-cause mortality and IFI mortality), IFI treatment outcome, AF-associated adverse effects/events/complications, resource use, episodes of neutropenic fever requiring hospital admission or outpatient management, AF resistance in fungi (non-invasive and invasive) and a Desirability of Outcome Ranking. The trial will have an internal pilot phase during the first 9 months. A mixed methods process evaluation will be integrated in parallel to the internal pilot phase and full trial, aiming to robustly assess how the intervention is delivered. Cost-effectiveness analysis will also be performed. DISCUSSION: The BioDriveAFS trial aims to further the knowledge of strategies that will safely optimise AF use through comparison of the clinical and cost-effectiveness of a biomarker-led diagnostic strategy versus prophylactic AF to prevent and manage IFI within acute leukaemia. The evidence generated from the study will help inform global clinical practice and approaches within antifungal stewardship. TRIAL REGISTRATION: ISRCTN11633399. Registered 24/06/2022.

Ventral Hernia Reconstruction with GORE ENFORM Biomaterial.

Introduction: Ventral hernia repair (VHR) is one of the most common surgeries performed in the United States. Degradable mesh is the recommended choice for patients presenting with high-risk co-morbidities or increased risk for infection. GORE® ENFORM BiomaterialTM is a biosynthetic degradable mesh that has recently been approved for use in ventral hernia reconstruction with no reports of its clinical outcomes. Methods: This study was a single surgeon case series. Patients were included in the study if they underwent VHR with GORE® ENFORM BiomaterialTM. The decision to use GORE® ENFORM BiomaterialTM was the senior surgeon's decision based on the patient's center for disease control classification. Patient comorbidities, hernia characteristics, postoperative hernia recurrence, and surgical site occurrences (SSOs) were collected at in-patient follow-up appointments and chart review. Patients were asked to complete preoperative and postoperative patient-reported outcomes (PROs) using the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity short form 3a and the hernia-specific quality of life (HerQLes) survey. Results: A total of 15 patients were included in this study. The average length of follow-up was 315 days. Postoperatively, 26.7% of patients had an SSO with 4 surgical site infections. Two patients required an operative washout with mesh removal. One patient experienced hernia recurrence. Eight of the 15 patients completed preoperative and postoperative PROs. Conclusion: This is the first clinical study to report the outcomes of ventral hernia repair using ENFORM mesh. These results show that Enform mesh is an option to consider in complex ventral hernia reconstruction.

Introduction: La réparation d'une hernie ventrale (RHV) est l'une des opérations les plus fréquentes aux États-Unis. Le treillis dégradable est le choix recommandé pour les patients ayant des affections connexes à haut risque ou qui sont vulnérables aux infections. Le biomatériau GORE® ENFORM est un treillis biosynthétique dégradable qui a récemment été approuvé pour la reconstruction des hernies ventrales et dont les résultats cliniques n'ont fait l'objet d'aucun rapport. Méthodologie : La présente étude était constituée d'une série de cas réalisée par un seul chirurgien. Les patients étaient inclus dans l'étude s'ils avaient subi une RHV à l'aide de biomatériau GORE® ENFORM. Le chirurgien en chef prenait la décision d'utiliser ce biomatériau d'après la classification du contrôle des maladies au centre du patient. Les chercheurs ont colligé les affections connexes du patient, les caractéristiques de la hernie, les récurrences de hernie postopératoire et les occurrences au foyer de l'opération (OFO) lors des rendez-vous de suivi et de l'examen des dossiers. Les patients ont été invités à préciser leurs résultats préopératoires et postopératoires (RPP) au moyen du formulaire court 3a sur l'intensité de la douleur tiré du système d'information des mesures de résultats déclarés par le patient (PROMIS) et du sondage sur la qualité de vie propre à la hernie (HerQLes). Résultats : Au total, 15 patients ont participé à l'étude et ont été suivis pendant une durée moyenne de 315 jours. Après l'opération, 26,7% des patients ont présenté une OFO ainsi que quatre infections au foyer de l'opération. Deux patients ont eu besoin d'un lessivage opératoire et du retrait du treillis. Un patient a subi une récurrence de la hernie. Huit des 15 patients ont rempli les RDP avant et après l'opération. Conclusion : Il s'agit de la première étude clinique à déclarer les résultats cliniques de la réparation d'une hernie ventrale à l'aide du treillis ENFORM. Ces résultats démontrent que le treillis Enform peut être envisagé pour la reconstruction d'une hernie ventrale complexe.

A ketogenic diet enhances fluconazole efficacy in murine models of systemic fungal infection.

Invasive fungal infections are a significant public health concern, with mortality rates ranging from 20% to 85% despite current treatments. Therefore, we examined whether a ketogenic diet could serve as a successful treatment intervention in murine models of Cryptococcus neoformans and Candida albicans infection in combination with fluconazole-a low-cost, readily available antifungal therapy. The ketogenic diet is a high-fat, low-carbohydrate diet that promotes fatty acid oxidation as an alternative to glycolysis through the production of ketone bodies. In this series of experiments, mice fed a ketogenic diet prior to infection with C. neoformans and treated with fluconazole had a significant decrease in fungal burden in both the brain (mean 2.66 ± 0.289 log10 reduction) and lung (mean 1.72 ± 0.399 log10 reduction) compared to fluconazole treatment on a conventional diet. During C. albicans infection, kidney fungal burden of mice in the keto-fluconazole combination group was significantly decreased compared to fluconazole alone (2.37 ± 0.770 log10-reduction). Along with higher concentrations of fluconazole in the plasma and brain tissue, fluconazole efficacy was maximized at a significantly lower concentration on a keto diet compared to a conventional diet, indicating a dramatic effect on fluconazole pharmacodynamics. Our findings indicate that a ketogenic diet potentiates the effect of fluconazole at multiple body sites during both C. neoformans and C. albicans infection and could have practical and promising treatment implications.IMPORTANCEInvasive fungal infections cause over 2.5 million deaths per year around the world. Treatments for fungal infections are limited, and there is a significant need to develop strategies to enhance antifungal efficacy, combat antifungal resistance, and mitigate treatment side effects. We determined that a high-fat, low-carbohydrate ketogenic diet significantly potentiated the therapeutic effect of fluconazole, which resulted in a substantial decrease in tissue fungal burden of both C. neoformans and C. albicans in experimental animal models. We believe this work is the first of its kind to demonstrate that diet can dramatically influence the treatment of fungal infections. These results highlight a novel strategy of antifungal drug enhancement and emphasize the need for future investigation into dietary effects on antifungal drug activity.

Challenges for global antibiotic regimen planning and establishing antimicrobial resistance targets: implications for the WHO Essential Medicines List and AWaRe antibiotic book dosing.

SUMMARYThe World Health Organisation's 2022 AWaRe Book provides guidance for the use of 39 antibiotics to treat 35 infections in primary healthcare and hospital facilities. We review the evidence underpinning suggested dosing regimens. Few (n = 18) population pharmacokinetic studies exist for key oral AWaRe antibiotics, largely conducted in homogenous and unrepresentative populations hindering robust estimates of drug exposures. Databases of minimum inhibitory concentration distributions are limited, especially for community pathogen-antibiotic combinations. Minimum inhibitory concentration data sources are not routinely reported and lack regional diversity and community representation. Of studies defining a pharmacodynamic target for ß-lactams (n = 80), 42 (52.5%) differed from traditionally accepted 30%-50% time above minimum inhibitory concentration targets. Heterogeneity in model systems and pharmacodynamic endpoints is common, and models generally use intravenous ß-lactams. One-size-fits-all pharmacodynamic targets are used for regimen planning despite complexity in drug-pathogen-disease combinations. We present solutions to enable the development of global evidence-based antibiotic dosing guidance that provides adequate treatment in the context of the increasing prevalence of antimicrobial resistance and, moreover, minimizes the emergence of resistance.

Determination of minimum inhibitory concentrations using machine-learning-assisted agar dilution.

Effective policy to address the global threat of antimicrobial resistance requires robust antimicrobial susceptibility data. Traditional methods for measuring minimum inhibitory concentration (MIC) are resource intensive, subject to human error, and require considerable infrastructure. AIgarMIC streamlines and standardizes MIC measurement and is especially valuable for large-scale surveillance activities. MICs were measured using agar dilution for n = 10 antibiotics against clinical Enterobacterales isolates (n = 1,086) obtained from a large tertiary hospital microbiology laboratory. Escherichia coli (n = 827, 76%) was the most common organism. Photographs of agar plates were divided into smaller images covering one inoculation site. A labeled data set of colony images was created and used to train a convolutional neural network to classify images based on whether a bacterial colony was present (first-step model). If growth was present, a second-step model determined whether colony morphology suggested antimicrobial growth inhibition. The ability of the AI to determine MIC was then compared with standard visual determination. The first-step model classified bacterial growth as present/absent with 94.3% accuracy. The second-step model classified colonies as "inhibited" or "good growth" with 88.6% accuracy. For the determination of MIC, the rate of essential agreement was 98.9% (644/651), with a bias of -7.8%, compared with manual annotation. AIgarMIC uses artificial intelligence to automate endpoint assessments for agar dilution and potentially increases throughput without bespoke equipment. AIgarMIC reduces laboratory barriers to generating high-quality MIC data that can be used for large-scale surveillance programs. IMPORTANCE: This research uses modern artificial intelligence and machine-learning approaches to standardize and automate the interpretation of agar dilution minimum inhibitory concentration testing. Artificial intelligence is currently of significant topical interest to researchers and clinicians. In our manuscript, we demonstrate a use-case in the microbiology laboratory and present validation data for the model's performance against manual interpretation.

State of the Art: Advances in Hernia Care.

The field of hernia surgery has seen many recent advances and continues to evolve. Care of the hernia patient begins preoperatively by ensuring adequate preparation for surgery with surgeons now having the opportunity to accurately predict risk which can aid with informed consent. Imaging studies can now help surgeons diagnose and plan hernia surgery on an individual level based on hernia characteristics as well as abdominal wall musculature. In the operating room, new technology and surgical techniques have allowed surgeons to become increasingly sophisticated with goals of reducing tension on midline closures, utilizing minimally invasive and robotic techniques, and availability of new and varied mesh prosthetics. While modest improvements in outcomes have been witnessed by these advances, there is still opportunity for improvement which will be realized by continued research, use of registries, and education and training. Hernia prevention strategies focusing on minimally invasive surgery, laparotomy closure, and the use of prophylactic mesh will also help with the burden of incisional hernias. These advances in hernia surgery have led to the new field of Abdominal Core Health which helps represent this evolving and growing new subspecialty of general surgery.

Molecular pharmacodynamics of meropenem for nosocomial pneumonia caused by Pseudomonas aeruginosa.

Hospital-acquired pneumonia (HAP) is a leading cause of morbidity and mortality, commonly caused by Pseudomonas aeruginosa. Meropenem is a commonly used therapeutic agent, although emergent resistance occurs during treatment. We used a rabbit HAP infection model to assess the bacterial kill and resistance pharmacodynamics of meropenem. Meropenem 5 mg/kg administered subcutaneously (s.c.) q8h (±amikacin 3.33-5 mg/kg q8h administered intravenously[i.v.]) or meropenem 30 mg/kg s.c. q8h regimens were assessed in a rabbit lung infection model infected with P. aeruginosa, with bacterial quantification and phenotypic/genotypic characterization of emergent resistant isolates. The pharmacokinetic/pharmacodynamic output was fitted to a mathematical model, and human-like regimens were simulated to predict outcomes in a clinical context. Increasing meropenem monotherapy demonstrated a dose-response effect to bacterial kill and an inverted U relationship with emergent resistance. The addition of amikacin to meropenem suppressed the emergence of resistance. A network of porin loss, efflux upregulation, and increased expression of AmpC was identified as the mechanism of this emergent resistance. A bridging simulation using human pharmacokinetics identified meropenem 2 g i.v. q8h as the licensed clinical regimen most likely to suppress resistance. We demonstrate an innovative experimental platform to phenotypically and genotypically characterize bacterial emergent resistance pharmacodynamics in HAP. For meropenem, we have demonstrated the risk of resistance emergence during therapy and identified two mitigating strategies: (i) regimen intensification and (ii) use of combination therapy. This platform will allow pre-clinical assessment of emergent resistance risk during treatment of HAP for other antimicrobials, to allow construction of clinical regimens that mitigate this risk.IMPORTANCEThe emergence of antimicrobial resistance (AMR) during antimicrobial treatment for hospital-acquired pneumonia (HAP) is a well-documented problem (particularly in pneumonia caused by Pseudomonas aeruginosa) that contributes to the wider global antimicrobial resistance crisis. During drug development, regimens are typically determined by their sufficiency to achieve bactericidal effect. Prevention of the emergence of resistance pharmacodynamics is usually not characterized or used to determine the regimen. The innovative experimental platform described here allows characterization of the emergence of AMR during the treatment of HAP and the development of strategies to mitigate this. We have demonstrated this specifically for meropenem-a broad-spectrum antibiotic commonly used to treat HAP. We have characterized the antimicrobial resistance pharmacodynamics of meropenem when used to treat HAP, caused by initially meropenem-susceptible P. aeruginosa, phenotypically and genotypically. We have also shown that intensifying the regimen and using combination therapy are both strategies that can both treat HAP and suppress the emergence of resistance.

Antimicrobial treatment imprecision: an outcome-based model to close the data-to-action loop.

Health-care systems, food supply chains, and society in general are threatened by the inexorable rise of antimicrobial resistance. This threat is driven by many factors, one of which is inappropriate antimicrobial treatment. The ability of policy makers and leaders in health care, public health, regulatory agencies, and research and development to deliver frameworks for appropriate, sustainable antimicrobial treatment is hampered by a scarcity of tangible outcome-based measures of the damage it causes. In this Personal View, a mathematically grounded, outcome-based measure of antimicrobial treatment appropriateness, called imprecision, is proposed. We outline a framework for policy makers and health-care leaders to use this metric to deliver more effective antimicrobial stewardship interventions to future patient pathways. This will be achieved using learning antimicrobial systems built on public and practitioner engagement; solid implementation science; advances in artificial intelligence; and changes to regulation, research, and development. The outcomes of this framework would be more ecologically and organisationally sustainable patterns of antimicrobial development, regulation, and prescribing. We discuss practical, ethical, and regulatory considerations involved in the delivery of novel antimicrobial drug development, and policy and patient pathways built on artificial intelligence-augmented measures of antimicrobial treatment imprecision.

Forecasting The Impact of the 2023 Current Procedural Terminology Coding Changes On Ventral Hernia Work Relative Value Units. A Cross-Sectional Study.

BACKGROUND: In January 2023, significant changes were implemented to ventral hernia repair Current Procedural Terminology codes, with new codes replacing previous codes. The new codes were assigned a 0-day global period. The impact of these changes on clinical productivity remains unclear. Our objective was to forecast the impact of Current Procedural Terminology changes on ventral hernia-related work relative value units using historical data. METHODS: Ventral hernia repairs performed between March 2021 and December 2022 on adults by a single surgeon with available 90-day follow-up were retrospectively retrieved from the Abdominal Core Health Quality Collaborative. Demographic, hernia, and operative and postoperative data were collected. The ventral hernia repairs were coded twice using the previous and new Current Procedural Terminology codes, and work relative value units were calculated using both systems. The median work relative value units per case were compared using the Wilcoxon signed-rank test. RESULTS: A total of 143 ventral hernia repairs were included. The median age was 59 years, and 50% of patients were male. Median hernia width and length were 3.5 and 5.0 cm, respectively. The most common ventral hernia types were incisional 57% and umbilical 33%. Twenty percent of hernias were recurrent, and 99% were elective repairs. 49% of the procedures were open, 30% robotic, and 21% laparoscopic. Component separation was performed in 16%. The median length of stay was 0.0, and the median number of 90-day outpatient postoperative visits was 1.0. The new Current Procedural Terminology coding system was associated with a higher median 90-day work relative value units per case (14.1) than the previous system (13.8) (P = .002). Subset analysis identified statistically higher median 90-day work relative value units per case using the new versus previous Current Procedural Terminology codes for hernias with the largest defect dimension >10 cm (23.3 vs 18.8), umbilical/epigastric/Spigelian hernias (9.2 vs 7.1), recurrent hernias (20.1 vs 17.3) and open ventral hernia repairs (9.8 vs 7.1), all P < .05. Median 90-day work relative value units per case were statistically lower using the new versus previous codes for non-recurrent (11.6 vs 13.8) and incarcerated/strangulated (14.8 vs 14.9) hernias, all P < .05. In the new coding system, postoperative care within 90-days contributed to a median of 1.3 work relative value units per case (9% of total 90-day work relative value units). CONCLUSION: We forecast that in our practice, the 2023 ventral hernia repair Current Procedural Terminology changes will result in a modest impact on clinical productivity. The impact of these changes on a particular practice depends on surgical practice patterns and ventral hernia case mix.