Inhibitory effect of gallium nitrate against Staphylococcus aureus and its action on the formation of biofilms on titanium surfaces

Abstract

Under the era of seeking new potential agents able to weaken the development and spread of multi-resistant bacteria towards traditional drugs, the use of the semimetal gallium (Ga3+) has stood out as an important strategy due to its physicochemical characteristics. This study aimed to investigate the effect of gallium nitrate [Ga(NO3)3], an inorganic antimicrobial agent, against the growth and biofilm formation of Staphylococcus aureus. The inhibitory concentration of gallium nitrate was determined in a 96-well microtiter plate in Muller Hinton broth. The potential of the antimicrobial agent to inhibit biofilm formation by S. aureus on titanium surfaces was evaluated by Scanning Electron Microscopy (SEM). The cytotoxicity potential of Ga(NO3)3 was determined on Hamster lung cells. The results showed that the IC50 of gallium nitrate against S. aureus was 1.40 µM, while SEM images revealed that concentrations above 90 µM completely inhibited biofilm formation by S. aureus. This research has shown promising results regarding gallium nitrate’s potential of inhibiting the growth of both planktonic and sessile S. aureus cells. In addition, coating titanium surfaces with Ga(NO3)3 would be an extra alternative to prevent implant-associated infections due to its non-toxicity to cells.