Hospital-acquired pneumonia, including ventilator-associated pneumonia (VAP) due to difficult-to-treat-resistant (DTR) Gram-negative bacteria, contributes significantly to morbidity and mortality in ICUs. In the era of COVID-19, the incidences of secondary nosocomial pneumonia and the demand for invasive mechanical ventilation have increased dramatically with extremely high attributable mortality. Treatment options for DTR pathogens are limited. Therefore, an increased interest in high-dose nebulized colistin methanesulfonate (CMS), defined as a nebulized dose above 6 million IU (MIU), has come into sight. Herein, the authors present the available modern knowledge regarding high-dose nebulized CMS and current information on pharmacokinetics, clinical studies, and toxicity issues. A brief report on types of nebulizers is also analyzed. High-dose nebulized CMS was administrated as an adjunctive and substitutive strategy. High-dose nebulized CMS up to 15 MIU was attributed with a clinical outcome of 63%. High-dose nebulized CMS administration offers advantages in terms of efficacy against DTR Gram-negative bacteria, a favorable safety profile, and improved pharmacokinetics in the treatment of VAP. However, due to the heterogeneity of studies and small sample population, the apparent benefit in clinical outcomes must be proven in large-scale trials to lead to the optimal use of high-dose nebulized CMS.

Cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators have been reported to improve lung function and reduce CF exacerbations. We aimed to investigate the efficacy of CFTR-modulators in CF-associated liver disease (CFLD) during long-term treatment. Longitudinal data were collected from genetically confirmed adult CF patients receiving CFTR-modulators. CFLD was diagnosed using conventional criteria combined with liver stiffness measurement (LSM). A total of 57 patients [56.1% male; median age at baseline (T0), 26 years (interquartile range [IQR], 23–35)] were included. Patients received lumacaftor/ivacaftor and/or elexacaftor/tezacaftor/ivacaftor for a median of 43 months (range, 15–123) until last assessment (T2). The prevalence of CFLD decreased from 15 (26.3%) at T0 to 8 (14.0%) at T2 (p = 0.016), and no new cases of CFLD were observed. Median LSM decreased from 6.2 (IQR 4.9–8.0) to 5.0 kPa (IQR 4.1–6.2) in the overall cohort (p < 0.001) and from 10.2 (IQR 6.8–13) to 6.2 kPa (IQR 5.0–12.4) in the CFLD subgroup (p = 0.025). Mild, transient fluctuations in liver enzymes occurred in 26.3% of patients. In conclusion, adults with CF receiving long-term CFTR modulators, showed improvement of liver disease assessed by ultrasonography and transient elastography. At the last assessment, half of the patients no longer met the criteria for CFLD.