Clinical Research Directory

Early Optimization of Ceftazidime Regimen in Critical Care

Hospital-acquired infections, most of which are caused by Gram-negative bacteria, are common in intensive care units and have a major impact on patient prognosis. Patient survival in severe sepsis and septic shock depends on the early administration of appropriate antibiotic therapy, with mortality increasing by 7.6% for each hour of delay, justifying the probabilistic use of broad-spectrum antibiotics such as ceftazidime, an essential betalactamine, particularly used for its activity against Pseudomonas aeruginosa, a frequent pathogen in nosocomial infections. It is currently recommended that ceftazidime should initially be administered as a 2g loading dose, followed by maintenance treatment by continuous infusion, at a dose adapted to renal function. The recommended dosage regimen, with its 2g loading dose, was developed using the median value of parameters from a pharmacokinetic model. This explains the findings of many critical care studies, which have found that 40-60% of patients initially have concentrations below target with the recommended dosing regimen. In the context of critical care, maintaining concentrations within the target therapeutic range is difficult due to variations in the elimination clearance of ceftazidime. Ceftazidime is mainly eliminated by the kidneys. Critical patients may have increased glomerular filtration rate, or, conversely, impaired renal function, with rapid variations in the event of severe infection. This leads to high intra- and inter-individual variability, and increases the risk of antibiotic under- or overdose when the maintenance dose is administered at a fixed dose (6g/d continuously). This high variability can also be observed in the volume of distribution (capillary leakage, oedema, perfusion volumes, effusions ...). In order to propose an individualised dosing regimen, we therefore propose an iterative randomised study to : * Step 1: FORTOPTIM\_1 Evaluation of an optimised dosage regimen based on literature data compared with the standard psological regimen. * Step 2: FORTOPTIM\_2 Build a pharmacokinetic model from the prospective data obtained in step 1. Based on this model, an individualised dosage regimen (loading dose and maintenance dose) will be obtained for step 3. * Step 3: FORTOPTIM\_3 Prospectively evaluate in a randomised trial the individualised dosing regimen previously defined (Step 2) by comparing it to the best dosing regimen determined in Step 1 or to the standard dosing regimen if there is no significant difference in Step 1.

Investigating the Impact of Sepsis Phenotypes on Antibiotic Treatment in Patients With Severe Pneumonia and Sepsis

Aim of the research: To find out why antibiotics work differently in certain patients with severe pneumonia and sepsis. Background: Individuals can become very unwell from pneumonia, sometimes requiring admission to hospital or even the intensive care unit (ICU). In some cases, pneumonia can lead to a condition called sepsis, which can be deadly if not treated quickly. In the UK, approximately 30,000 patients die from pneumonia every year. Clinicians use antibiotic injections to treat life-threatening infections such as severe pneumonia. After being injected into the bloodstream, antibiotics quickly spread throughout the body, attacking the infection. Antibiotics are eventually broken down and removed from the body by the kidneys and other organs. However, antibiotics fail to achieve the same consistent result for every patient. This may be to do with the way the antibiotics travel through and are removed from the body, leading to different antibiotic levels in the blood at any one time. Low antibiotic levels can result in worse outcomes and antibiotic resistance. Patients can be grouped based on how their immune system reacts to infections. The SIPRES Study aims to explore if these previously described groups explain the difference in antibiotic levels in patients with severe pneumonia and sepsis. Procedures: We will study how adult patients with severe pneumonia respond when treated with the most commonly used antibiotic in the ICU called piperacillin/tazobactam. Alongside information on how quickly patients get better and how long they need to stay in hospital or in ICU, we will collect blood samples to measure antibiotic levels and assess each patient's immune system at two time points during their treatment. This will allow us to measure antibiotic levels in blood at different times and group patients based on their immune system reaction to infection. We will describe the range of antibiotic levels seen in the different immune system reaction groups using mathematical and statistical models. Patient involvement: We are working closely with people who have experienced severe pneumonia and will work with two patient partners and a patient advisory group to help shape this research. Patient contributors have already shaped the development of the funding application and identified important study outcomes. Patients we have spoken to are concerned over the appropriate dosing of antibiotics and appreciate the need for improved and precise approaches to treating severe infections. Moving forward, patient partners will help finalise the protocol, develop patient and public facing materials, provide their perspective on the study results and shape plans to share the outcomes of the study more broadly. Potential impact: The SIPRES Study will help identify a group of patients at risk of low antibiotic levels in blood, who are less likely to improve with treatment and more likely to develop antibiotic resistance. Mathematical models that can help clinicians personalise antibiotic dosing for each critically ill patient with severe pneumonia will be developed. Findings have the potential to limit the development of antibiotic resistance and help patients survive and get better faster so that they can return to their normal daily lives. Individualised dosing for patients with low antibiotic levels, as opposed to 'one size fits all' prescribing, also has the potential to more efficiently allocate scarce resources to those who will benefit the most.

Measurement of Intestinal Permeability in Intensive Care Patients With Single or Multiple Organ Failure

Multivisceral failure syndrome (MVFS) in humans is associated with a very high risk of mortality, ranging between 30 and 50%. This syndrome is associated with significant systemic inflammation and a high risk of bacteremia, the origin of which is not always identified. Among the possible causes of bacteremia, digestive translocation is the most probable but has not been formally proven to date. This translocation is made possible by the numerous cellular and metabolic alterations secondary to MVFS, which can lead to increased intestinal barrier permeability. Intestinal permeability is currently not systematically evaluated in clinical practice in humans. This increased intestinal permeability, associated with the presence of inflammatory markers and a septic state, has been studied in several animal models ranging from the fruit fly (Drosophila) to the mouse. These studies have shown a high risk of mortality associated with increased intestinal permeability. We propose to use this methodology in intensive care patients with at least one organ failure to investigate the link between increased intestinal permeability and survival chances.

Comparative Study of Clinical Outcomes and Safety Between Colistin and Tigecycline

Objective from this study to compare the clinical outcomes and safety between colistin and tigecycline for multi-drug resistant gram negative bacteria.

The Gut Microbiome - Source of Sepsis and Novel Target in Intensive Care Units?

Here, the investigators propose to study host responses to reduced microbiome complexity driven by treatment with broad spectrum antibiotics in patients with severe infections or sepsis. The proposal aims to combine holistic approaches with emerging experimental technologies to investigate the complex interactions between the gut microbiota and its host and assess the impact of specific bacterial communities on longevity and stress responses. A strong focus of this study will also be placed on microbiome dysbiosis and secondary impacts on short- and long-term brain dysfunction using clinical, laboratory and imaging procedures.