Sulfonamides complexed with metals as mycobacterial biofilms inhibitors

Rapidly growing mycobacteria (RGM) are found in non-sterile water and often associated with severe post-surgical infections and affect immunocompromised patients. In addition, RGM can prevent the host's immune response and have the ability to adhere to and form biofilms on biological and synthetic substrates, making pharmacological treatment difficult because conventional antimicrobials are ineffective against biofilms. Thus, there is an urgent need for new antimicrobial compounds that can overcome these problems. In this context, sulfonamides complexed with Au, Cd, Ag, Cu, and Hg have shown excellent activity against various microorganisms. Considering the importance of combating RGM-associated infections, this study aimed to evaluate the activity of sulfonamide metal complexes against RGM biofilm. The sulfonamides were tested individually for their ability to inhibit mycobacterial formation and destroy the preformed biofilm of standard RGM strains, such as Mycobacterium abscessus, M. fortuitum, and M. massiliense. All sulfonamides complexed with metals could reduce, at subinhibitory concentrations, the adhesion and biofilm formation of three RGM species in polystyrene tubes. It is plausible that the anti-biofilm capacity of the compounds is due to the inhibition of c-di-GMP synthesis, which is an important signal for RGM biofilm formation. Hence, the impacts and scientific contribution of this study are based on the discovery of a potential new therapeutic option against RGM-associated biofilm infections. Sulfonamides complexed with metals have proven to be a useful and promising tool to reduce microbial adhesion on inert surfaces, stimulating the improvement of methodologies to insert compounds as new antibacterial and coating agents for medical and hospital materials.