Mechanistic and phenotypic studies of bicarinalin, BP100 and colistin action on Acinetobacter baumannii

Acinetobacter baumannii has been identified by the WHO as a high priority pathogen. It can be resistant to multiple antibiotics and colistin sulphate is often used as a last-resort treatment. However, the potentially severe side-effects of colistin are well documented and this study compared the bactericidal and anti-biofilm activity of two synthetic nature-inspired antimicrobial peptides, bicarinalin and BP100, with colistin. The minimum bactericidal concentration (MBC) against planktonic A. baumannii was approximately 0.5 μg/ml for colistin sulphate and ∼4 μg/ml for bicarinalin and BP100. A. baumannii commonly occurs as a biofilm and biofilm removal assay results highlighted that both bicarinalin and BP100 had significantly greater potential than colistin. Atomic force microscopy (AFM) showed dramatic changes in A. baumannii cell size and surface conformity when treated with peptide concentrations at and above the MBC. Scanning electron microscopy (SEM) visualised the reduction of biofilm coverage and cell surface changes as peptide concentration increased. Liposome assays revealed that these peptides most likely act as pore-forming agents in the membrane. Bicarinalin and BP100 may be effective therapeutic alternatives to colistin against A. baumannii infections but further research is required to assess if they elicit cytotoxicity issues in patients

The potential of photo-deposited silver coatings on Foley catheters to prevent urinary tract infections

Catheter-associated urinary tract infection (CAUTI) represents one of the most common causes of morbidity and mortality. The resistance demonstrated by many microorganisms to conventional antibiotic therapies and the increasing health-care costs have recently encouraged the definition of alternative preventive strategies,which can have a positive effect in the management of infections. Antimicrobial urinary catheters have been developed through the photo-chemical deposition of silver coatings on the external and luminal surfaces. The substrates are exposed to ultraviolet radiation after impregnation into a silver-based solution, thus inducing the in situ synthesis of silver particles. The effect of the surface treatment on the material was investigated through scanning electron microscopy (SEM) and silver ion release measurements. The ability of microorganisms commonly associated with urinary tract infections was investigated in terms of bacterial viability, proliferation and biofilm development, using Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis as target organisms. The silver coatings demonstrated good distribution of silver particles to the substrate, and proved an effective antibacterial capability in simulated biological conditions. The low values of silver ion release demonstrated the optimum adhesion of the coating. The results indicated a good potential of silver-based antimicrobialmaterials for prevention of catheter-associated urinary tract infection

Comparison of the uptake of apoptotic and necrotic cells by macrophages

macrophages recognise and engulf apoptotic and necrotic cell via the same mechanisms including PS and Rac1 dependency. Apoptotic and necrotic cell compete with each other for the uptake by macrophages in a dose dependent manner with the same efficiency.MSc/MAmolekuláris biológiaangolBiokémia-genomik

Traitement biocide de l’eau usée par la polarisation en régime pulsé

La résistance des germes totaux contenus dans les eaux usées a été évaluée en fonction du temps au traitement, d’une part, par l’acide hypochloreux de l’eau de javel commerciale et celui produit in situ en milieu chloruré par électrolyse en polarisation potentiostatique, et d’autre part, par la polarisation en régime pulsé. Lors de cette étude, la polarisation en régime statique ou pulsé était de l’ordre de ± 2 V/Ag/AgCl. Pour cette tension et en polarisation pulsée, nous avons mis en évidence une fréquence optimale d’inactivation des germes estimée à 1 kHz. Dans cette contribution, nous étudions pour les mêmes germes l’effet biocide de la polarisation en régime pulsé bipolaire en fonction du temps, de la fréquence et de la tension pour des valeurs imposées supérieures à ± 2 V/Ag/AgCl. Les résultats de cette étude montrent une inactivation croissante des germes en fonction de la tension appliquée. À ± 10 V/Ag/AgCl, un effet biocide plus important est observé à une fréquence de 10 kHz

Characterization of bacterial biofilms formed on urinary catheters

International audienc

N,N’-Substituted 1,2,5 Thiadiazolidine 1,1-Dioxides: Synthesis, Selected Chemical and Spectral Proprieties and Antimicrobial Evaluation â€

The sulfamide functional group is increasingly relevant in both medicinal and bioorganic chemistry. We report here practical access to a series of N2,N5-substituted five-membered cyclosulfamides. The five-membered heterocyclic motif was prepared starting from proteogenic amino acids and chlorosulfonyl isocyanate via the Mitsunobu reaction. Selected chemical and spectral proprieties and the antimicrobial evaluation of these compounds are detailed

Selected Chemical and Spectral Proprieties and Antimicrobial Evaluation †

Abstract: The sulfamide functional group is increasingly relevant in both medicinal and bioorganic chemistry. We report here practical access to a series of N2,N5-substituted five-membered cyclosulfamides. The five-membered heterocyclic motif was prepared starting from proteogenic amino acids and chlorosulfonyl isocyanate via the Mitsunobu reaction. Selected chemical and spectral proprieties and the antimicrobial evaluation of these compounds are detailed

Ecological engineering strategy to clean up wastewater in arid area

International audienc