Pseudomonas Aeruginosa Infection

The purpose of this study is to evaluate the safety and tolerability of a single intravenous dose of MP101 administered in addition to standard antibiotic therapy in adult patients with acute Pseudomonas aeruginosa pneumonia. The study will also assess the pharmacokinetic and pharmacodynamic characteristics of MP101 and its antibacterial activity, including changes in P. aeruginosa burden in sputum and changes in susceptibility to MP101 and concomitant antibiotics.

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.

The aim of this study is to observe specimens of bronchoalveolar lavage fluid from patients using a reflection enhanced dark-field scattering microscopy. By observing parameters such as the size, morphology, scattering intensity, and movement speed of pathogens, combined with the clinical characteristics of patients, a rapid diagnosis of Pseudomonas aeruginosa infection can be made. At the same time, the bronchoalveolar lavage fluid samples of patients infected with Pseudomonas aeruginosa before and after treatment were compared, and the quantity and vitality of Pseudomonas aeruginosa were observed to judge the efficacy of antibiotics.