Atividade antibacteriana e antibiofilme de um complexo de rutênio ligado a antraceno contra bactérias envolvidas em infecções relacionadas à assistência à saúde

Abstract

Antimicrobial resistance is an increasing problem which has become one of the biggest threats to global health, especially in relation to the inefficiency of antimicrobial therapies. In the hospital context, this fact becomes even more worrying, since many deaths are caused by Healthcare-Associated Infections (HAI), often caused by resistant bacteria. Given this scenario, ruthenium complexes stand out as an alternative to current drugs, since previous works showed the antibacterial activity of these compounds. The present study aimed to evaluate the antimicrobial and antibiofilm activity of the [Ru(bpy)2(bpy-ant)]2+ complex against the clinically important bacteria Staphylococcus aureus ATCC25923, Staphylococcus aureus ATCC700698 (MRSA), Staphylococcus epidermidis ATCC12228, Staphylococcus epidermidis ATCC35984 and Escherichia coli ATCC11303. To evaluate the antimicrobial activity, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were analyzed. Antibiofilm activity was tested using the crystal violet (CV) staining method of the biomass, for subsequent quantification and enumeration of viable cells, by counting colony forming units (CFU). Gram-positive bacteria S. aureus and S. epidermidis were more susceptible to the compound when compared to Gram-negativebacteria E. coli. The MIC results ranged from 7.8 to 125 µg/mL, whereas in relation to CBM, bactericidal concentrations of 15.6 to 250 µg/mL were obtained. In the quantification of biomass, the reductions ranged from 6.3 to 99.9% for all strains tested, while in the enumeration of viable cells, the decreases were 0.01 logs until the total reduction of CFUs. In conclusion, the potential of the ruthenium complex to control microbial growth as well as to inhibit the formation of biofilms was verified.