Supramolecular assemblies of cationic lipid, antibiotics and polymers: preparation, characterization and activity against multidrug resistant bacteria and fast growing mycobacteria.

Author(s)

Letícia Dias de Melo Carrasco

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2016-07-08

Examining board members

Ana Maria Carmona Ribeiro; Mauricio da Silva Baptista; Kelly Ishida

• Advisor: Ana Maria Carmona Ribeiro; Jorge Luiz Mello Sampaio

Abstract

Supramolecular assemblies combining cationic lipid dioctadecyldimethylammonium bromide (DOD) and polymers, such as sodium carboxymethylcellulose (CMC) and poly(diallyldimethylammonium chloride) (PDDA), were prepared as nanoparticles (NPs), in the absence or presence of traditional antibiotic, such as clarithromycin (CLA). NPs prepared by electrostatic attraction between DOD bilayer fragments (BF), CMC and PDDA were evaluated against clinical strains of multidrug resistant (MDR) microorganisms, such as Pseudomonas aeruginosa MDR, Klebsiella pneumoniae producer of KPC carbapenemase enzyme, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans fluconazole resistant, by plating and colony forming unities counting. DOD BF/CMC/PDDA NPs display high and broad-spectrum activity against MDR microrganisms, and PDDA is the excellent biocidal component in the NPs. The mechanism of antimicrobial action shows that NPs disassembly in the presence of microrganisms, with biopolymers withdrawn from the cell wall, as observed by scanning electron microscopy, consecutively lysing bacterial membrane as determined from the leakage of inner phosphorylated compounds. In this work there have also been developed NPs, based on lipid and polymers, as carriers for CLA. Ethanolic solution co-solubilizing CLA/DOD was injected in CMC aqueous solution, yielding colloidaly stable and anionic NPs, that were further added of PDDA solution, yielding stable and cationic NPs. CLA/DOD/CMC NPs and CLA/DOD/CMC/PDDA NPs incorporated CLA at doses high enough to inhibit M. abscessus growth inside macrophages or in biofilms. Larger CLA doses were toxic to macrophages while lower CLA doses reduced toxicity to macrophages despite their high antimicrobial activity. Cationic CLA NPs exhibited substantial toxicity against macrophages at the PDDA concentrations tested. The particulate nature of these CLA NPs possibly increases intracellular CLA retention in comparison to free CLA, probably extending CLA activity against intracellular pathogens. In conclusion, supramolecular assemblies combining cationic lipid and polymers, with or without traditional antibiotics, may find multiple possibilities of applications at pharmaceutical, medical, food and biotecnological fields. (AU)

• FAPESP's process: 12/24534-1 - Supramolecular assemblies of cationic lipid, antibiotics and polymers: preparation, characterization and activity against multiresistant bacteria and fast-growing mycobacteria
• Grantee: Letícia Dias de Melo Carrasco
• Support Opportunities: Scholarships in Brazil - Doctorate