Identification of antimicrobial activity among new sulfonamide metal complexes for combating rapidly growing mycobacteria

Mycobacteriosis is a type of infection caused by rapidly growing mycobacteria (RGM), which can vary from localized illness, such as skin disease, to disseminated disease. Amikacin, cefoxitin, ciprofloxacin, clarithromycin, doxycycline, imipenem and sulfamethoxazole are antimicrobial drugs chosen to treat such illnesses; however, not all patients obtain the cure. The reason why the treatment does not work for those patients is related to the fact that some clinical strains present resistance to the existing antimicrobial drugs; thereby, the research of new therapeutic approaches is extremely relevant. The coordination of antimicrobial drugs to metals is a promising alternative in the development of effective compounds against resistant microorganisms. Sulfonamides complexed with Au, Cd, Ag, Cu, and Hg have shown excellent activity against a variety of microorganisms. Considering the importance of fighting against infections associated with RGM, the objective of this study is to evaluate the antimycobacterial activity of metal complexes of sulfonamides against RGM. Complexed sulfonamides activity were individually tested and in association with trimethoprim. The minimum inhibitory concentration (MIC) and time-kill curve of compounds against the standard strains of RGM [ Mycobacterium abscessus (ATCC 19977), Mycobacterium fortuitum (ATCC 6841) and Mycobacterium massiliense (ATCC 48898)] was determined. The interaction of sulfonamides with trimethoprim was defined by inhibitory concentration index fractional for each association. The results showed that sulfonamides complexed whit metals have outstanding antimicrobial activity when compared to free sulfamethoxazole, bactericidal activity and synergistic effect when combined with trimethoprim.