Enhanced antibacterial activity of the gentamicin against multidrug-resistant strains when complexed with Canavalia ensiformis lectin.

The lectins are carbohydrate-binding proteins that are highly specific to sugar groups associated to other molecules. In addition to interacting with carbohydrates, a number of studies have reported the ability of these proteins to modulate the activity of several antibiotics against multidrug-resistant (MDR) strains. In this study, we report the enhanced antibacterial activity of the gentamicin against MDR strains when complexed with a lectin from Canavalia ensiformis seeds (ConA). Hemagglutination activity test and intrinsic fluorescence spectroscopy revealed that the gentamicin can interact with ConA most likely via the carbohydrate recognition domain (CRD) with binding constant (K) value estimated of (0.44 ± 0.04) x 10 M. Furthermore, the minimum inhibitory concentrations (MIC) obtained for ConA against all strains studied were not clinically relevant (MIC ≥ 1024 μg/mL). However, when ConA was combined with gentamicin, a significant increase in antibiotic activity was observed against Staphylococcus aureus and Escherichia coli. The present study showed that ConA has an affinity for gentamicin and modulates its activity against MDR strains. These results indicate that ConA improves gentamicin performance and is a promising candidate for structure/function analyses.