Antibacterial and Antibiofilm Properties of Ticagrelor

Fifty µl of bacterial broth containing 10⁵ CFU was added to microtiter plate wells containing eight serially double-diluted ticagrelor concentrations to make the final volume 100 µL and the final ticagrelor (Sigma-Aldrich) concentrations 50 μg/ml to 0.75 μg/ml followed by incubation for 24 h at 37°C. Antibacterial activity was measured by determining the OD at 600 nm. The minimum bactericidal concentration (MBC) was determined by quantifying bacteria from wells with no visible growth, using the drop dilution method (Naghili et al., 2013 (link)). The minimum ticagrelor concentration that reduced bacterial concentration by more than 99.9% was taken as MBC. To determine the antibiofilm activity of ticagrelor, we used previously reported biofilm assay procedures with a slight modification (Singh et al., 2019 (link)). The culture supernatant was discarded and the residual biofilm was fixed with 2% sodium acetate for 10 min. Then the biofilm was stained overnight with crystal violet followed by rinsing with tap water and air drying. The crystal violet retained was then reconstituted with absolute ethanol, and OD values were measured at 570 nm. The experiments were performed in triplicates. S. aureus growth in ticagrelor diluent dimethylformamide (DMF) (4.15%) was used as a positive control while the sterile DMF was used as a negative control.