Ação da carboximetilquitosana isolada e em combinação com sais metálicos contra a formação de biofilmes por bactérias Gram-positivas

Abstract

The carboxymethylation is a modification which aims to extend the variety of pharmaceutical and medical applications because of chitosan to increase the solubility in various modes of physiological interest. Furthermore, the CMC has low toxicity. Silver, copper and zinc in the form of salts have been widely used as antimicrobial agents due to their activity against different strains. The present study intends to demonstrate the effect of CMC alone and in combination with silver nitrate, copper sulfate and zinc sulfate against biofilm formation by grampositive bacteria. For this purpose, the synthesis and characterization of CMC was conducted, evaluated the toxicity of biopolymer isolated and in combination with the salts of the metals by the brine shrimp lethality test and demonstrated the antimicrobial activity and the potential of the isolated compounds and in combination against biofilm formation by gram-positive bacteria. The results demonstrate the successful synthesis yield of 190% degree of substitution of 1.87, the groups of substitutions were confirmed by spectroscopy in the infrared region. No toxicity was observed for the CMC Artemia salina, salts showed varying toxicity when they were combined with the CMC has decreased toxicity. The antimicrobial activity of CMC was not detected in all tested concentrations (MIC> 1000μg ml-1 ), silver nitrate alone and in combination with CMC showed 1000μg ml-1 MIC, copper sulfate and zinc sulfate either alone or in combination with the CMC presented CMI> 1000μg ml-1 . Whereas biofilm formation, evidence of the inhibitory action of CMC against Gram-positive bacteria, and in combination with silver nitrate, this phenomenon was enhanced. Other metal salts in combination with the biopolymer does not significantly potentiated the inhibitory activity of a biofilm formation, both the total biomass as the metabolic activity of the cells associated with this structure. The CMC demonstrated antibiofilm activity showing its potential in the control of this important virulence mechanism.