Avaliação in vitro da atividade antimicrobiana e antibiofilme da quitosana de Ucides cordatus contra bacterias gram-negativas resistentes aos antimicrobianos

Abstract

Chitosan, derived from the deacetylation of chitin, has gained prominence due to its broad potential for applications in biomedical fields and the development of technologies in the food industry, particularly because of its antimicrobial activity. Traditionally extracted from the exoskeleton of crustaceans, the growing demand for this biopolymer has driven the exploration of the crab Ucides cordatus, found in mangrove ecosystems along the Atlantic coast. Thus, the present study aimed to evaluate the antimicrobial and antibiofilm activities of Ucides cordatus chitosan extracts against antimicrobial-resistant Gram-negative bactéria and to formulate an appropriate coating composition for application on coalho cheese. Antibacterial activity was determined by assessing the minimum inhibitory concentration and minimum bactericidal concentration at concentrations ranging from 5 to 0.009 mg/mL. Antibiofilm activity was evaluated using inhibition and eradication assays, quantified by the crystal violet staining method. To determine the appropriate coating formulation for coalho cheese, the wettability technique was employed through contact angle measurements on the surface. Toxicity assessments were conducted using the extracts and coating solutions in cellular models. With a degree of deacetylation of 92%, Ucides cordatus chitosan demonstrated good antimicrobial properties, showing inhibition of Gram-negative strains at bactericidal concentrations of 0.625 mg/mL, as well as inhibition of biofilm formation by approximately 98% in Pseudomonas aeruginosa and 86% in Escherichia coli resistant strains isolated from coalho cheese. These concentrations were found to be non-toxic. Regarding coating potential, based on the wettability technique on coalho cheese surfaces, the composition containing 2.0% Ucides cordatus chitosan with 0.2% glycerol was identified as the most suitable for coating application. The results obtained were comparable to those of commercially available chitosan, thus highlighting the biotechnological potential of Ucides cordatus chitosan as an antimicrobial agent in the biomedical field and the food industry.