Effect of algae and plant lectins on planktonic growth and biofilm formation in clinically relevant bacteria and yeasts

This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250 μg/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins.This study was supported by the CAPES (Brazil) under the BEX NT 2052/11NT3 Project, by the IBB-CEB and FCT (Portugal), by the European Community Fund FEDER, and by the COMPETE Program under the auspices of the PTDC/SAU-ESA/646091/2006/FCOMP-01-0124-FEDER-007480 Project. Kyria Santiago Nascimento, Alexandre Holanda Sampaio, Benildo Sousa Cavada, and Edson Holanda Teixeira are Senior Fellows of CNPq. Mr. David Martin helped with the English editing of the paper that was also revised by AJE (American Journal Experts)