A clinical predictive model of candidaemia by Candida auris in previously colonized critically ill patients.

OBJECTIVES: Candida auris is an emerging multidrug-resistant fungus that has been associated with nosocomial outbreaks with high rates of mortality and transmission. The aim of this study was to perform a retrospective cohort analysis of risk factors and to build a scoring method for estimating the risk of candidaemia in colonized critically ill patients. METHODS: We performed a retrospective observational cohort study of patients aged ≥15 years colonized by C. auris in the 3-year period between March 2016 and March 2019. Epidemiological, clinical, laboratory and microbiological data were collected. We developed a predictive model for candidaemia using elastic net multivariable logistic regression techniques, assessed its discriminative capacity, and internally validated it using bootstrap resampling. RESULTS: Two-hundred and six patients were enrolled in the cohort for derivation and internal validation. Thirty-seven out of 206 patients developed candidaemia. Total parenteral nutrition was the foremost risk factor (adjusted OR 3.73); previous surgery (adjusted OR 1.03), sepsis (adjusted OR 1.75), previous exposure to antifungal agents (adjusted OR 1.17), arterial catheters (adjusted OR 1.46), central venous catheters (adjusted OR 1.21), presence of advanced chronic kidney disease (adjusted OR 1.35) and multifocal colonization (adjusted OR of unifocal colonization 0.46) were proven to be independent predictors of candidaemia in our cohort. The corresponding area under the curve (AUC) of the elastic net regularized predictive model was 0.89 (95%CI 0.826; 0.951). After performing the internal validation by generating 500 bootstrap replications, the model still showed great accuracy, with a resulting AUC of 0.84. CONCLUSION: Our study provides evidence on the independent predisposing factors for candidaemia. It may help predict its estimated risk and may identify a high-risk population that could benefit from early or prophylactic antifungal treatment after external validation in other cohorts.

D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness.

Aquaporins (AQPs) play a physiological role in several organs and tissues, and their alteration is associated with disorders of water regulation. The identification of molecular interactions, which are crucial in determining the rate of water flux through the channel, is of pivotal role for the discovery of molecules able to target those interactions and therefore to be used for pathologies ascribable to an altered AQP-dependent water balance. In the present study, a mutational screening of human aquaporin-4 (AQP4) gene was performed on subjects with variable degrees of hearing loss. One heterozygous missense mutation was identified in a Spanish sporadic case, leading to an Asp/Glu amino acid substitution at position 184 (D184E). A BLAST analysis revealed that the amino acid D184 is conserved across species, consistently with a crucial role in the structure/function of AQP4 water channels. The mutation induces a significant reduction in water permeability as measured by the Xenopus laevis oocytes swelling assay and by the use of mammalian cells by total internal reflection microscopy. By Western blot, immunofluorescence and 2D Blue Native/SDS-PAGE we show that the reduction in water permeability is not ascribable to a reduced expression of AQP4 mutant protein or to its incorrect plasma membrane targeting and aggregation into orthogonal arrays of particles. Molecular dynamics simulation provided a molecular explanation of the mechanism whereby the mutation induces a loss of function of the channel. Substituting glutamate for aspartate affects the mobility of the D loop, which acquires a higher propensity to equilibrate in a "closed conformation", thus affecting the rate of water flux. We speculate that this mutation, combined with other genetic defects or concurrently with certain environmental stimuli, could confer a higher susceptibility to deafness.

Quinolizidinyl derivatives of bi- and tricyclic systems as potent inhibitors of acetyl- and butyrylcholinesterase with potential in Alzheimer's disease.

On the pattern of the potent and selective butyrylcholinesterase (BChE) inhibitors ethopropazine and Astra1397, sets of quinolizidinyl derivatives of bi- and tricyclic (hetero)aromatic systems were studied as dual, or BChE-selective inhibitors. All compounds exhibited activity against both cholinesterases, but inhibition of BChE was generally stronger, with submicromolar IC50 values for most of them (e.g. 15: IC50 versus BChE=0.15 µM; SI=47). However, in a subset of quinolizidinyl derivatives of 6-hydroxycoumarin an inverted selectivity for acetylcholinesterase (AChE) was observed (e.g. 46: IC50 versus AChE=0.35 µM; SI=0.06). Docking studies furnished a sound interpretation of the observed different enzyme activity. Several of the studied compounds have shown, in the past, additional pharmacological properties (as antagonism on presynaptic muscarinic autoreceptor; inhibition of enkephaline aminopeptidase and antipsychotic activity) of some relevance in Alzheimer's disease, and may, therefore, represent hits for the development of interesting single-entity multi-target drugs.